Modified release gamma-hydroxybutyrate formulations having improved pharmacokinetics

PRIOR APPLICATIONS

0001This application claims priority to <patcit id="pcit0001" dnum="US62365812"><text>United States Provisional Patent Application Nos. 62/365,812 (filed July 22, 2016</text></patcit>), <patcit id="pcit0002" dnum="US62399413B"><text>62/399,413 (filed September 25, 2016</text></patcit>), and <patcit id="pcit0003" dnum="US62474330B"><text>62/474,330 (filed March 21, 2017</text></patcit>). The content of the foregoing applications is hereby incorporated by reference and made a part hereof as if fully contained herein.

FIELD OF THE INVENTION

0002The present invention relates to modified release formulations of gamma-hydroxybutyrate having improved pharmacokinetic (PK) properties, and to therapeutic uses thereof.

BACKGROUND

0003Narcolepsy is a devastating disabling condition. The cardinal symptoms are excessive daytime sleepiness (EDS), cataplexy (a sudden loss of muscle tone triggered by strong emotions, seen in approximately 60% of patients), hypnogogic hallucination (HH), sleep paralysis (SP), and disturbed nocturnal sleep (DNS). Other than EDS, DNS is the most common symptom seen among narcolepsy patients.

0004The diagnosis of narcolepsy rests in part on clinical grounds. When narcolepsy is suspected, it is standard practice to administer an overnight polysomnogram (PSG) followed by a multiple sleep latency test (MSLT) to document the rapid eye movement (REM) abnormality that characterizes the disorder. On the MSLT a mean sleep latency less than or equal to 8 minutes and two or more sleep onset REM periods (SOREMPs) are required to confirm a diagnosis of Type 1 or Type 2 narcolepsy. It is also possible, but infrequently preferred, that narcolepsy be diagnosed by measuring hypocretin in the cerebrospinal fluid (CSF) in cases where the PSG and/ or MSLT is not completed. For these cases, a hypocretin concentration of less than 110 pg/nL confirms a narcolepsy Type 1 diagnosis.

0005One of the major treatments for narcolepsy is sodium oxybate, a neuroactive agent with a variety of Central Nervous System (CNS) pharmacological properties. The species is present endogenously in many tissues, where it acts as a neurotransmitter on a gamma-hydroxybutyrate (GHB) receptor (GHBR), and possesses neuromodulatory properties with significant effects on dopamine and gamma-Aminobutyric Acid (GABA). Studies have suggested that sodium oxybate improves Rapid Eye Movement Sleep (REM sleep, REMS) of narcoleptics in contrast to antidepressant drugs.

0006Sodium oxybate is also known as sodium 4-hydroxybutanoate, or gamma-hydroxybutyric acid sodium salt, and has the following chemical structure: <chemistry id="chem0001" num="0001"><img file="EP4623907A2_D0001.tif" /></chemistry>

0007Sodium oxybate is marketed commercially in the United States as Xyrem^®. The product is formulated as an immediate release liquid solution that is taken once immediately before bed, and a second time approximately 2.5 to 4 hours later, in equal doses. Sleep-onset can be dramatic and fast, and patients are advised to be sitting in bed when consuming the dose. The most commonly reported side effects are confusion, depressive syndrome, incontinence and sleepwalking.

0008When initiating treatment with sodium oxybate, careful titration up to an adequate level is essential both to obtain positive results and avoid adverse effects. The recommended starting dose is 4.5 g divided into 2 equal doses of 2.25 g, the first taken at bedtime and the second taken 2.5 to 4 hours later. The starting dosage can be decreased to 3.0 g/day or increased to as high as 9.0 g/day in increments of 1.5 g/day (0.75 g per dose). Two weeks are recommended between dosage adjustments to optimize reduction of daytime symptoms and minimize side effects. The ideal dose will provide an effective eight hours of sleep but, at the end of eight hours, very little of the drug will remain in the patient's bloodstream to affect the patient's wakefulness.

0009The requirement to take Xyrem^® twice each night is a substantial inconvenience to narcolepsy patients. The patient must typically set an alarm to take the second dose, which can interrupt ongoing productive sleep. Several efforts have been made to provide a once-nightly modified release dosage form of sodium oxybate, but none has yet received approval from the United States Food and Drug Administration ("FDA") or proven effective in the clinic.

0010One of the biggest drawbacks of these once-nightly formulations is the reduction in bioavailability that occurs when sodium oxybate is formulated in a modified release dosage form, as measured by the blood concentration / time area under the curve ("AUC"). <patcit id="pcit0004" dnum="US20120076865A1"><text>U.S. 2012/0076865 A1 by Allphin et al.</text></patcit> ("Allphin"), for example, conducted two separate crossover bioavailability trials involving three separate modified release formulations and an immediate release solution, and reported the following bioavailability results: <tables id="tabl0001" num="0001"><table frame="topbot"><tgroup cols="7" colsep="0"><colspec colnum="1" colname="col1" colwidth="12mm" /><colspec colnum="2" colname="col2" colwidth="18mm" align="center" /><colspec colnum="3" colname="col3" colwidth="16mm" align="center" /><colspec colnum="4" colname="col4" colwidth="28mm" align="center" /><colspec colnum="5" colname="col5" colwidth="23mm" align="center" /><colspec colnum="6" colname="col6" colwidth="33mm" align="center" /><colspec colnum="7" colname="col7" colwidth="31mm" align="center" /><thead><row valign="top"><entry namest="col1" nameend="col7" align="center">Summary of PK Parameters for Treatments A, B, C</entry></row><row><entry align="center" valign="top" /><entry>λ_z (1/hr)</entry><entry>T _1/2 (hr)</entry><entry valign="middle">Tmax (hr)<i>^a</i></entry><entry>Cmax (ug/ml)</entry><entry>AUClast (hr * ug/ml)</entry><entry>AUCinf (hr * ug/ml)</entry></row><row valign="top"><entry namest="col1" nameend="col7" align="center">Treatment A</entry></row></thead><tbody><row rowsep="0"><entry>N</entry><entry>29</entry><entry>29</entry><entry>29</entry><entry>29</entry><entry>29</entry><entry>29</entry></row><row rowsep="0"><entry>Mean</entry><entry>1.22</entry><entry>0.6</entry><entry>4.50 (0.5, 4.75)</entry><entry>130.79</entry><entry>350.84</entry><entry>351.2</entry></row><row rowsep="0"><entry>SD</entry><entry>0.27</entry><entry>0.13</entry><entry /><entry>31.52</entry><entry>116.74</entry><entry>116.74</entry></row><row rowsep="0"><entry>CV %</entry><entry>21.93</entry><entry>22.61</entry><entry /><entry>24.1</entry><entry>33.27</entry><entry>33.24</entry></row><row><entry>Mean</entry><entry>1.19</entry><entry>0.58</entry><entry /><entry>127.3</entry><entry>333.33</entry><entry>333.72-</entry></row></tbody></tgroup><tgroup cols="7" colsep="0"><colspec colnum="1" colname="col1" colwidth="12mm" /><colspec colnum="2" colname="col2" colwidth="18mm" align="center" /><colspec colnum="3" colname="col3" colwidth="16mm" align="center" /><colspec colnum="4" colname="col4" colwidth="28mm" align="center" /><colspec colnum="5" colname="col5" colwidth="23mm" align="center" /><colspec colnum="6" colname="col6" colwidth="33mm" align="center" /><colspec colnum="7" colname="col7" colwidth="31mm" align="center" /><thead valign="top"><row><entry namest="col1" nameend="col7" align="center">Treatment B</entry></row></thead><tbody><row rowsep="0"><entry>N</entry><entry>18</entry><entry>18</entry><entry>19</entry><entry>19</entry><entry>19</entry><entry>18</entry></row><row rowsep="0"><entry>Mean</entry><entry>0.62</entry><entry>1.22</entry><entry>2.00 (1.50, 5.00)</entry><entry>41.78</entry><entry>188.23</entry><entry>196.25</entry></row><row rowsep="0"><entry>SD</entry><entry>0.16</entry><entry>0.40</entry><entry /><entry>18.40</entry><entry>103.60</entry><entry>102.50</entry></row><row rowsep="0"><entry>CV %</entry><entry>26.44</entry><entry>32.58</entry><entry /><entry>44.03</entry><entry>55.04</entry><entry>52.23</entry></row><row><entry>Mean</entry><entry>0.59</entry><entry>1.17</entry><entry /><entry>38.46</entry><entry>163.80</entry><entry>173.33</entry></row></tbody></tgroup><tgroup cols="7" colsep="0"><colspec colnum="1" colname="col1" colwidth="12mm" /><colspec colnum="2" colname="col2" colwidth="18mm" align="center" /><colspec colnum="3" colname="col3" colwidth="16mm" align="center" /><colspec colnum="4" colname="col4" colwidth="28mm" align="center" /><colspec colnum="5" colname="col5" colwidth="23mm" align="center" /><colspec colnum="6" colname="col6" colwidth="33mm" align="center" /><colspec colnum="7" colname="col7" colwidth="31mm" align="center" /><thead valign="top"><row><entry namest="col1" nameend="col7" align="center">Treatment C</entry></row></thead><tbody><row rowsep="0"><entry>N</entry><entry>19</entry><entry>19</entry><entry>19</entry><entry>19</entry><entry>19</entry><entry>19</entry></row><row rowsep="0"><entry>Mean</entry><entry>0.74</entry><entry>0.99</entry><entry>2.50 (1.00, 5.00)</entry><entry>50.49</entry><entry>221.64</entry><entry>222.60</entry></row><row rowsep="0"><entry>SD</entry><entry>0.16</entry><entry>0.23</entry><entry /><entry>15.83</entry><entry>106.85</entry><entry>106.80</entry></row><row rowsep="0"><entry>CV %</entry><entry>22.25</entry><entry>22.93</entry><entry /><entry>31.35</entry><entry>48.21</entry><entry>47.98</entry></row><row><entry>Mean</entry><entry>0.72</entry><entry>0.96</entry><entry /><entry>48.10</entry><entry>200.08</entry><entry>201.12</entry></row></tbody></tgroup></table></tables><tables id="tabl0002" num="0002"><table frame="all"><tgroup cols="7"><colspec colnum="1" colname="col1" colwidth="14mm" /><colspec colnum="2" colname="col2" colwidth="13mm" align="center" /><colspec colnum="3" colname="col3" colwidth="13mm" align="center" /><colspec colnum="4" colname="col4" colwidth="29mm" align="center" /><colspec colnum="5" colname="col5" colwidth="15mm" align="center" /><colspec colnum="6" colname="col6" colwidth="17mm" align="center" /><colspec colnum="7" colname="col7" colwidth="16mm" align="center" /><thead valign="middle"><row><entry namest="col1" nameend="col7" align="center">Summary of OK Parameters for Treatments A, D, E</entry></row></thead><tbody valign="middle"><row><entry /><entry /><entry /><entry /><entry /><entry /><entry /></row><row><entry /><entry /><entry /><entry /><entry /><entry>AUClast</entry><entry>AUCinf</entry></row><row><entry /><entry>λ_z</entry><entry>T_1/2</entry><entry>Tmax (hr)<i>^a</i></entry><entry>Cmax</entry><entry>(hr *</entry><entry>(hr *</entry></row><row><entry /><entry>(1/hr)</entry><entry>(hr)</entry><entry /><entry>(ug/ml)</entry><entry>ug/ml)</entry><entry>ug/ml)</entry></row></tbody></tgroup><tgroup cols="7"><colspec colnum="1" colname="col1" colwidth="14mm" /><colspec colnum="2" colname="col2" colwidth="13mm" align="center" /><colspec colnum="3" colname="col3" colwidth="13mm" align="center" /><colspec colnum="4" colname="col4" colwidth="29mm" align="center" /><colspec colnum="5" colname="col5" colwidth="15mm" align="center" /><colspec colnum="6" colname="col6" colwidth="17mm" align="center" /><colspec colnum="7" colname="col7" colwidth="16mm" align="center" /><thead valign="middle"><row><entry namest="col1" nameend="col7" align="center">Treatment A</entry></row></thead><tbody valign="middle"><row><entry>N</entry><entry>30</entry><entry>30</entry><entry>30</entry><entry>30</entry><entry>30</entry><entry>30</entry></row><row><entry>Mean</entry><entry>1.08</entry><entry>0.71</entry><entry>4.50 (0.50, 5.50)</entry><entry>114.59</entry><entry>301.28</entry><entry>301.59</entry></row><row><entry>SD</entry><entry>0.31</entry><entry>0.27</entry><entry /><entry>27.91</entry><entry>100.85</entry><entry>100.87</entry></row><row><entry>CV %</entry><entry>29.00</entry><entry>37.90</entry><entry /><entry>24.36</entry><entry>33.47</entry><entry>33.45</entry></row><row><entry>Mean</entry><entry>1.03</entry><entry>0.6⁷</entry><entry /><entry>111.20</entry><entry>285.47</entry><entry>285.79</entry></row></tbody></tgroup><tgroup cols="7"><colspec colnum="1" colname="col1" colwidth="14mm" /><colspec colnum="2" colname="col2" colwidth="13mm" align="center" /><colspec colnum="3" colname="col3" colwidth="13mm" align="center" /><colspec colnum="4" colname="col4" colwidth="29mm" align="center" /><colspec colnum="5" colname="col5" colwidth="15mm" align="center" /><colspec colnum="6" colname="col6" colwidth="17mm" align="center" /><colspec colnum="7" colname="col7" colwidth="16mm" align="center" /><thead valign="middle"><row><entry namest="col1" nameend="col7" align="center">Treatment D</entry></row></thead><tbody valign="middle"><row><entry>N</entry><entry>30</entry><entry>30</entry><entry>30</entry><entry>30</entry><entry>30</entry><entry>30</entry></row><row><entry>Mean</entry><entry>0.46</entry><entry>1.63</entry><entry>0.75 (0.50, 2.50)</entry><entry>25.10</entry><entry>64.44</entry><entry>65.58</entry></row><row><entry>SD</entry><entry>0.14</entry><entry>0.47</entry><entry /><entry>7.33</entry><entry>20.36</entry><entry>20.26</entry></row><row><entry>CV %</entry><entry>30.27</entry><entry>29.00</entry><entry /><entry>29.20</entry><entry>31.60</entry><entry>30.90</entry></row><row><entry>Mean</entry><entry>0.44</entry><entry>1.56</entry><entry /><entry>24.10</entry><entry>61.31</entry><entry>62.55</entry></row></tbody></tgroup><tgroup cols="7"><colspec colnum="1" colname="col1" colwidth="14mm" /><colspec colnum="2" colname="col2" colwidth="13mm" align="center" /><colspec colnum="3" colname="col3" colwidth="13mm" align="center" /><colspec colnum="4" colname="col4" colwidth="29mm" align="center" /><colspec colnum="5" colname="col5" colwidth="15mm" align="center" /><colspec colnum="6" colname="col6" colwidth="17mm" align="center" /><colspec colnum="7" colname="col7" colwidth="16mm" align="center" /><thead valign="middle"><row><entry namest="col1" nameend="col7" align="center">Treatment E</entry></row></thead><tbody valign="middle"><row><entry>N</entry><entry>30</entry><entry>30</entry><entry>30</entry><entry>30</entry><entry>30</entry><entry>30</entry></row><row><entry>Mean</entry><entry>0.59</entry><entry>1.36</entry><entry>1.00 (0.50, 5.00)</entry><entry>59.52</entry><entry>242.30</entry><entry>243.80</entry></row><row><entry>SD</entry><entry>0.20</entry><entry>0.64</entry><entry /><entry>17.72</entry><entry>117.15</entry><entry>116.79</entry></row><row><entry>CV %</entry><entry>34.57</entry><entry>46.91</entry><entry /><entry>29.77</entry><entry>48.35</entry><entry>47.91</entry></row><row><entry>Mean</entry><entry>0.55</entry><entry>1.25</entry><entry /><entry>56.89</entry><entry>216.33</entry><entry>218.12</entry></row><row><entry /><entry /><entry /><entry /><entry /><entry /><entry /></row></tbody></tgroup><tgroup cols="7" rowsep="0"><colspec colnum="1" colname="col1" colwidth="14mm" align="justify" /><colspec colnum="2" colname="col2" colwidth="13mm" /><colspec colnum="3" colname="col3" colwidth="13mm" /><colspec colnum="4" colname="col4" colwidth="29mm" /><colspec colnum="5" colname="col5" colwidth="15mm" /><colspec colnum="6" colname="col6" colwidth="17mm" /><colspec colnum="7" colname="col7" colwidth="16mm" /><tbody><row><entry namest="col1" nameend="col7">Treatment A: Two 3 g IR doses administered four hours apart Treatment B: One 6 g CR dose administered at time zero (no IR component) Treatment C: One 6 g CR dose administered at time zero (no IR component) Treatment D: One 4 g dose including IR and CR fractions administered at time zero Treatment E: One 8 g dose including IR and CR fractions administered at time zero</entry></row></tbody></tgroup></table></tables>

0011As can be seen, mean AUC_inf, which measures the total exposure of the body to sodium oxybate for a given dose, was significantly less for the doses having a modified release component when compared to the immediate release doses. Mean AUC_inf for Treatment B, which included the exact same dose of sodium oxybate as Treatment A, was only 56% of the mean AUC_inf for Treatment A; mean AUC_inf for Treatment C, which also included the same dose of sodium oxybate as Treatment A, was only 63% of the mean AUC_inf for Treatment A; mean AUC_inf for Treatment E was only 81% of the mean AUC_inf of Treatment A, even though Treatment E dosed 2 g more of sodium oxybate than Treatment A, which, compared to same dose, represented only 61% of the mean AUC_inf of Treatment A . Mean AUC_inf for Treatment D was only 22% of the mean AUC_inf of Treatment A, although Treatment D dosed 2 g less of sodium oxybate than Treatment A, which, compared to same dose, represented only 33% of the mean AUC_inf of Treatment A. As shown in <figref idref="f0006">Figures 12</figref> and <figref idref="f0007">14</figref> of <patcit id="pcit0005" dnum="US20120076865A1"><text>U.S. 2012/0076865 A1</text></patcit>, Allphin's formulations also suffered from an excess of sodium oxybate remaining in the bloodstream at 8 hours.

0012<patcit id="pcit0006" dnum="US8193211B"><text>U.S. Patent No. 8,193,211 to Liang et al.</text></patcit> ("Liang") reports even lower bioavailability from his once-nightly formulations. Liang developed several enterically coated delayed release formulations of sodium oxybate, and tested these formulations in dogs alongside an immediate release formulation to compare the relative pharmacokinetics (PK) of these formulations. The results of Liang's testing are reported below: <tables id="tabl0003" num="0003"><table frame="topbot"><tgroup cols="5" colsep="0"><colspec colnum="1" colname="col1" colwidth="31mm" /><colspec colnum="2" colname="col2" colwidth="27mm" /><colspec colnum="3" colname="col3" colwidth="27mm" /><colspec colnum="4" colname="col4" colwidth="19mm" /><colspec colnum="5" colname="col5" colwidth="19mm" /><thead valign="middle"><row><entry namest="col1" nameend="col5" align="center">Mean GHB Concentrations (ug/mL)</entry></row><row><entry rowsep="0" align="center" /><entry rowsep="0" align="center" /><entry namest="col3" nameend="col5" align="left">Period</entry></row><row rowsep="0"><entry morerows="1" rowsep="1" align="center">Time Point (Hr)</entry><entry align="center">1</entry><entry align="center">2</entry><entry align="center">3</entry><entry align="center">4</entry></row><row><entry align="center">DR1-w/ Acid</entry><entry align="center">DRI-No Acid</entry><entry align="center">IR</entry><entry align="center">DR2</entry></row></thead><tbody valign="middle"><row rowsep="0"><entry align="center">0</entry><entry align="center">0.00</entry><entry align="center">0.00</entry><entry align="center">0.00</entry><entry align="center">0.00</entry></row><row rowsep="0"><entry align="center">0.5</entry><entry align="center">0.00</entry><entry align="center">0.00</entry><entry align="center">116.04</entry><entry align="center">0.00</entry></row><row rowsep="0"><entry align="center">1</entry><entry align="center">0.00</entry><entry align="center">4.76</entry><entry align="center">248.27</entry><entry align="center">1.52</entry></row><row rowsep="0"><entry align="center">2</entry><entry align="center">4.99</entry><entry align="center">11.62</entry><entry align="center">195.51</entry><entry align="center">32.52</entry></row><row rowsep="0"><entry align="center">3</entry><entry align="center">26.31</entry><entry align="center">31.88</entry><entry align="center">117.56</entry><entry align="center">100.99</entry></row><row rowsep="0"><entry align="center">4</entry><entry align="center">35.14</entry><entry align="center">38.26</entry><entry align="center">47.21</entry><entry align="center">100.57</entry></row><row rowsep="0"><entry align="center">5</entry><entry align="center">29.18</entry><entry align="center">34.77</entry><entry align="center">8.74</entry><entry align="center">54.99</entry></row><row rowsep="0"><entry align="center">6</entry><entry align="center">21.09</entry><entry align="center">27.83</entry><entry align="center">0.00</entry><entry align="center">23.42</entry></row><row rowsep="0"><entry align="center">7</entry><entry align="center">11.25</entry><entry align="center">9.13</entry><entry align="center">0.00</entry><entry align="center">7.52</entry></row><row rowsep="0"><entry align="center">8</entry><entry align="center">8.67</entry><entry align="center">2.53</entry><entry align="center">0.00</entry><entry align="center">0.34</entry></row><row rowsep="0"><entry align="center">10</entry><entry align="center">1.43</entry><entry align="center">3.03</entry><entry align="center">0.00</entry><entry align="center">0.00</entry></row><row rowsep="0"><entry align="center">12</entry><entry align="center">0.98</entry><entry align="center">0.67</entry><entry align="center">0.00</entry><entry align="center">0.00</entry></row><row rowsep="0"><entry align="center">14</entry><entry align="center">0.43</entry><entry align="center">0.00</entry><entry align="center">0.00</entry><entry align="center">0.00</entry></row><row rowsep="0"><entry align="center">Tmax (Hr)</entry><entry align="center">4.2</entry><entry align="center">5.2</entry><entry align="center">1.2</entry><entry align="center">3.7</entry></row><row rowsep="0"><entry align="center">Cmax (ug/mL)</entry><entry align="center">38.77</entry><entry align="center">58.44</entry><entry align="center">249.5</entry><entry align="center">112.7</entry></row><row rowsep="0"><entry align="center">AUClast</entry><entry align="center">134.3</entry><entry align="center">162.6</entry><entry align="center">601.0</entry><entry align="center">318.4</entry></row><row><entry align="center">Rel BA,</entry><entry align="center">22%</entry><entry align="center">27%</entry><entry align="center">100%</entry><entry align="center">53%</entry></row></tbody></tgroup><tgroup cols="5" rowsep="0"><colspec colnum="1" colname="col1" colwidth="31mm" align="justify" /><colspec colnum="2" colname="col2" colwidth="27mm" /><colspec colnum="3" colname="col3" colwidth="27mm" /><colspec colnum="4" colname="col4" colwidth="19mm" /><colspec colnum="5" colname="col5" colwidth="19mm" /><tbody><row><entry namest="col1" nameend="col5">DR1-w/ Acid: Two 1 g DR capsules administered at time zero DR1-No Acid: Two 1 g DR capsules administered at time zero IR: Two 1 g IR capsules administered at time zero DR2: Two 1 g DR capsules administered at time zero</entry></row></tbody></tgroup></table></tables>

0013As can be seen, by encapsulating the sodium oxybate in an enteric / delayed release coating, Liang decreased the AUC of the sodium oxybate significantly. One of the formulations, DR1-w/ Acid, had a relative bioavailability of only 22% compared to the immediate release dosage form. DR2 had the greatest relative bioavailability, but still only 53% compared to the immediate release dosage form. One can easily calculate that any of the envisioned combinations of immediate release (IR) components and delayed release (DR) components as described in col. 5 lines 3 to 28 of <patcit id="pcit0007" dnum="US8193211B"><text>U.S. Patent No. 8,193,211</text></patcit> will not give a relative bioavailability greater than 78%.

0014All of these formulations are inconvenient for at least two reasons: (1) the low relative bioavailability necessitates an increase in the dose compared to current IR treatments which already require a large dose (4.5 to 9 g a day), and (2) when provided in the form of pills, a patient must swallow around 4 to 9 pills per dose, which is a serious inconvenience for the patient and potential drawback for patient compliance.

0015Various other techniques are known for formulating modified release dosage forms including, for example, the techniques described in <patcit id="pcit0008" dnum="US8101209B"><text>U.S. Patent No. 8,101,209 to Legrand et al.</text></patcit> ("Legrand"). Legrand provides a system ensuring that the active ingredient is released with certainty from the modified release dosage form by means of a dual mechanism of "time-dependent" and "pH-dependent" release. Legrand did not describe any dosage forms for delivering sodium oxybate or other forms of gamma-hydroxybutyrate.

0016Another drawback of Xyrem^® is the high level of the daily dose, generally 7.5g or 9g of sodium oxybate taken daily over long periods of time. This represents a very high sodium intake which is not recommended in persons with high blood pressure, risk of cardiovascular disease, stroke or coronary heart disease (See <nplcit id="ncit0001" npl-type="b"><text>WHO. Guideline: Sodium intake for adults and children. Geneva, World Health Organization (WHO), 2012</text></nplcit>.).

0017Accordingly, one object of the present invention is to provide modified release formulations of gamma-hydroxybutyrate that are administered only once at bed-time with improved dissolution and pharmacokinetic profiles.

0018Another object of the present invention is to provide modified release formulations of gamma-hydroxybutyrate that optimize the bioavailability of the gamma-hydroxybutyrate, and roughly approximate the bioavailability of an equal dose of an immediate release liquid solution of sodium oxybate administered twice nightly.

0019Still another object of the present invention is to provide once-nightly modified release formulations of gamma-hydroxybutyrate that roughly approximate or exceed the bioavailability of an equal dose of an immediate release solution of sodium oxybate administered twice nightly, across the entire therapeutic range of sodium oxybate doses.

0020Yet another object of the present invention is to provide modified release formulations of gamma-hydroxybutyrate which, 8 hours after administration, produce very little residual drug content in the bloodstream of most patients but still similar to the one observed after administration of an equal dose of an immediate release liquid solution of sodium oxybate administered twice nightly.

0021Yet another object of the present invention is to improve the therapeutic effectiveness and safety profile of gamma-hydroxybutyrate based on novel dissolution and pharmacokinetic profiles.

0022Yet another object of the present invention is to provide modified release formulations of gamma-hydroxybutyrate that yield a similar pharmacokinetic profile compared to an immediate release liquid solution of sodium oxybate administered twice nightly while potentially giving a reduced dose.

0023Yet another object of the present invention is to provide modified release formulations of gamma-hydroxybutyrate that allow once daily administration and reduced dose compared to the commercial treatment Xyrem^®.

0024Yet another object of the present invention is to provide a convenient dosage form of gamma-hydroxybutyrate that can be easily swallowed.

0025Yet another object of the present invention is to provide modified release formulations of gamma-hydroxybutyrate that are administered only once at bed-time with improved dissolution and pharmacokinetic profiles and reduced sodium content compared to an immediate release liquid solution of sodium oxybate administered twice nightly.

SUMMARY OF INVENTION

0026As the prior art demonstrates, it is extremely difficult to find a modified release formulation of gamma-hydroxybutyrate which, when administered only once nightly, has a comparable bioavailability to an immediate release liquid solution of sodium oxybate administered twice nightly. Even if such a formulation could be found, it probably still would not be satisfactory because the dose of gamma-hydroxybutyrate differs among individuals, and the size of the dose affects the amount of drug absorbed through the GI tract. I.e., even if the prior art formulations achieved comparable bioavailability at one dose - which they do not - they would not be comparable at other doses.

0027The inventors have discovered a novel relationship between the in vitro release profile of gamma-hydroxybutyrate modified release formulations and in vivo absorption which permits, for the first time, a modified release formulation of gamma-hydroxybutyrate that approximates the bioavailability of a twice-nightly equipotent immediate release liquid solution of sodium oxybate, and that does so across a range of therapeutic doses. In particular, the inventors have discovered that a modified release formulation of gamma-hydroxybutyrate that rapidly releases half of its gamma-hydroxybutyrate in 0.1N hydrochloric acid dissolution medium, and rapidly releases the other half of its gamma-hydroxybutyrate in phosphate buffer pH 6.8 dissolution medium, approximates or exceeds the in vivo bioavailability of an equipotent immediate release liquid solution of sodium oxybate administered twice nightly. This can be seen by comparing the formulations of Examples 1 and 4, which satisfy the dissolution requirements ofthe present invention and achieve the necessary bioavailability for a commercial formulation, with the Comparative formulation of Example 7, which exhibited a dissolution profile similar to prior art dissolution profiles, and did not achieve the necessary bioavailability for a commercial formulation.

0028This phenomenon is observed especially with higher doses of gamma-hydroxybutyrate. For example, the inventors have discovered that a modified release composition of gamma-hydroxybutyrate according to the invention administered once approximately two hours after a standardized evening meal at the dose equivalent to 7.5g of sodium oxybate results in a similar pharmacokinetic profile as an immediate release liquid solution of sodium oxybate given in two separate equal doses of 4.5g of sodium oxybate each administered at t₀ and t_4h.

0029The modified release formulations of gamma-hydroxybutyrate preferably have both immediate release and modified release portions. The release of gamma-hydroxybutyrate from the immediate release portion is practically uninhibited, and occurs almost immediately in 0.1N hydrochloric acid dissolution medium. In contrast, while the modified release portion also preferably releases its gamma-hydroxybutyrate almost immediately when fully triggered, the release is not triggered until a predetermined lag-time or the drug is subjected to a suitable dissolution medium such as a phosphate buffer pH 6.8 dissolution medium. Without wishing to be bound by any theory, it is believed that this rapid release in two dissolution media compresses the blood concentration vs. time curve in vivo, resulting in a relative bioavailability of gamma-hydroxybutyrate comparable to or greater than an equipotent dose of an immediate-release liquid solution of sodium oxybate administered twice nightly.

0030Formulations that achieve this improved bioavailability can be described using several different pharmacokinetic and in vitro dissolution parameters. In a first principal embodiment, the invention provides a modified release formulation of gamma-hydroxybutyrate, preferably comprising immediate release and modified release portions, wherein a 7.5 g dose of the formulation has been shown to achieve a mean AUC_inf of greater than 340 hr<img file="EP4623907A2_D0002.tif" /> microgram/mL.

0031In a second principal embodiment, the invention provides a modified release formulation of gamma-hydroxybutyrate, preferably comprising immediate release and modified release portions, wherein a 7.5 g dose of the formulation has been shown to achieve a mean AUC_inf of greater than 340 hrxmicrogram/mL, and a mean C_8h that is from 50% to 130% of the mean C_8h provided by an equal dose of an immediate release liquid solution of sodium oxybate administered at t₀ and t_4h in equally divided doses approximately two hours after a standardized evening meal.

0032In a third principal embodiment, the invention provides a modified release formulation of gamma-hydroxybutyrate, preferably comprising immediate release and modified release portions, wherein the formulation releases (a) at least 80% of its gamma-hydroxybutyrate at 3 hours when tested in a dissolution apparatus 2 according to USP 38 <711> in 900 mL of 0.05M monobasic potassium phosphate buffer pH 6.8 at a temperature of 37° C and a paddle speed of 75 rpm, and (b) from 10% to 65%, of its gamma-hydroxybutyrate at one hour and three hours when tested in a dissolution apparatus 2 according to USP 38 <711> in 900 mL of 0.1N hydrochloric acid at a temperature of 37°C and a paddle speed of 75 rpm.

0033In a fourth principal embodiment, the invention provides a modified release formulation of gamma-hydroxybutyrate, comprising immediate release and modified release portions, wherein (a) the formulation releases at least 80% of its gamma-hydroxybutyrate at 3 hours, when tested in a dissolution apparatus 2 according to USP 38 <711> in 900 mL of 0.05M monobasic potassium phosphate buffer pH 6.8 at a temperature of 37° C and a paddle speed of 75 rpm, (b) the formulation releases from 10% to 65%, of its gamma-hydroxybutyrate at one hour and three hours when tested in a dissolution apparatus 2 according to USP 38 <711> in 900 mL of 0.1N hydrochloric acid at a temperature of 37°C and a paddle speed of 75 rpm, and (c) the modified release portion releases greater than 80% of its gamma-hydroxybutyrate at 3 hours in a dissolution test started in 750 mL of 0.1N hydrochloric acid for 2 hours then switched to 950 mL 0.05M monobasic potassium phosphate buffer adjusted to pH 6.8 at a temperature of 37°C and a paddle speed of 75 rpm.

0034In a fifth principal embodiment, the invention provides a modified release formulation of gamma-hydroxybutyrate, comprising immediate release and modified release portions, wherein (a) the formulation releases at least 80% of its gamma-hydroxybutyrate at 3 hours, when tested in a dissolution apparatus 2 according to USP 38 <711> in 900 mL of 0.05M monobasic potassium phosphate buffer pH 6.8 at a temperature of 37° C and a paddle speed of 75 rpm, (b) the formulation releases 10% to 65%, of its gamma-hydroxybutyrate at one hour and at three hours when tested in a dissolution apparatus 2 according to USP 38 <711> in 900 mL of 0.1N hydrochloric acid at a temperature of 37°C and a paddle speed of 75 rpm, (c) the formulation releases greater than 60% of its gamma-hydroxybutyrate at 10 hours when tested in a dissolution apparatus 2 according to USP 38 <711> in 900 mL of 0.1N hydrochloric acid at a temperature of 37°C and a paddle speed of 75 rpm, and (d) the modified release portion releases greater than 80% of its gamma-hydroxybutyrate at 3 hours in a dissolution test started in 750 mL of 0.1N hydrochloric acid for 2 hours then switched to 950 mL 0.05M monobasic potassium phosphate buffer adjusted to pH 6.8 at a temperature of 37°C and a paddle speed of 75 rpm.

0035In a sixth principal embodiment, the invention provides a modified release formulation of gamma-hydroxybutyrate, comprising immediate release and modified release portions, wherein (a) a 7.5 g dose of the formulation has been shown to achieve a mean AUC_inf of greater than 340 hr<img file="EP4623907A2_D0003.tif" /> microgram/mL, and a mean C_8h that is from 50% to 130%, of the mean C_8h provided by an equal dose of an immediate release liquid solution of sodium oxybate administered at t₀ and t_4h in equally divided doses approximately two hours after a standardized evening meal, and (b) the formulation releases (i) at least 80% or 90% of its gamma-hydroxybutyrate at 3 hours when tested in a dissolution apparatus 2 according to USP 38 <711> in 900 mL of 0.05M monobasic potassium phosphate buffer pH 6.8 at a temperature of 37° C and a paddle speed of 75 rpm, and (ii) from 10% to 65%, of its gamma-hydroxybutyrate at one hour and three hours when tested in a dissolution apparatus 2 according to USP 38 <711> in 900 mL of 0.1N hydrochloric acid at a temperature of 37°C and a paddle speed of 75 rpm, and (c) the modified release portion releases greater than 80% of its gamma-hydroxybutyrate at 3 hours in a dissolution test started in 750 mL of 0.1N hydrochloric acid for 2 hours then switched to 950 mL 0.05M monobasic potassium phosphate buffer adjusted to pH 6.8 at a temperature of 37°C and a paddle speed of 75 rpm.

0036In a seventh principal embodiment, the invention provides a modified release formulation of gamma-hydroxybutyrate comprising immediate release and modified release portions, wherein: (a) said immediate release portion releases greater than 80% of its gamma-hydroxybutyrate at one hour when tested in a dissolution apparatus 2 according to USP 38 <711> in 900 mL of 0.1N hydrochloric acid at a temperature of 37°C and a paddle speed of 75 rpm; (b) said modified release portion releases less than 20% of its gamma-hydroxybutyrate at one hour when tested in a dissolution apparatus 2 according to USP 38 <711> in 900 mL of 0.1N hydrochloric acid at a temperature of 37°C and a paddle speed of 75 rpm; and (c) said modified release portion releases greater than 80% of its gamma-hydroxybutyrate at three hours when tested in a dissolution apparatus 2 according to USP 38 <711> in 900 mL of 0.05M monobasic potassium phosphate buffer pH 6.8 at a temperature of 37° C and a paddle speed of 75 rpm.

0037In an eighth principal embodiment, the invention provides a modified release formulation of gamma-hydroxybutyrate comprising immediate release and modified release portions, wherein: (a) said immediate release portion releases greater than 80% of its gamma-hydroxybutyrate at one hour when tested in a dissolution apparatus 2 according to USP 38 <711> in 900 mL of 0.1N hydrochloric acid at a temperature of 37°C and a paddle speed of 75 rpm; (b) said modified release portion releases less than 20% of its gamma-hydroxybutyrate at one hour when tested in a dissolution apparatus 2 according to USP 38 <711> in 900 mL of 0.1N hydrochloric acid at a temperature of 37°C and a paddle speed of 75 rpm; (c) said modified release portion releases greater than 80% of its gamma-hydroxybutyrate at three hours when tested in a dissolution apparatus 2 according to USP 38 <711> in 900 mL of 0.05M monobasic potassium phosphate buffer pH 6.8 at a temperature of 37° C and a paddle speed of 75 rpm; and (d) said modified release portion releases greater than 80% of its gamma-hydroxybutyrate at 3 hours in a dissolution test started in 750 mL of 0.1N hydrochloric acid for 2 hours then switched to 950 mL 0.05M monobasic potassium phosphate buffer adjusted to pH 6.8 at a temperature of 37°C and a paddle speed of 75 rpm.

0038In a ninth principal embodiment, the invention provides a modified release formulation of gamma-hydroxybutyrate, preferably comprising immediate release and modified release portions, wherein 4.5g, 6g, 7.5g, and 9g doses of the formulation have been shown to achieve a relative bioavailability (RBA) of greater than 80% when compared to an equal dose of an immediate release liquid solution of sodium oxybate administered at t₀ and t_4h in equally divided doses, when administered approximately two hours after a standardized evening meal.

0039In a tenth principal embodiment, the invention provides a modified release formulation of gamma-hydroxybutyrate, preferably comprising immediate release and modified release portions, wherein 4.5g and 9g doses of the formulation have been shown to achieve a relative bioavailability (RBA) of greater than 80% when compared to an equal dose of an immediate release liquid solution of sodium oxybate administered at t₀ and t_4h in equally divided doses, when administered approximately two hours after a standardized evening meal.

0040In an eleventh principal embodiment, the invention provides a modified release formulation of gamma-hydroxybutyrate, preferably comprising immediate release and modified release portions, that yields a plasma concentration versus time curve when administered once nightly at a strength of 4.5g, 6.0 g or 7.5g approximately two hours after a standardized evening meal substantially as depicted in <figref idref="f0006">Figure 12</figref> or <figref idref="f0007">Figure 13</figref> for the corresponding strength.

0041In a twelfth principal embodiment, the invention provides a modified release formulation of gamma-hydroxybutyrate, preferably comprising immediate release and modified release portions, that yields a plasma concentration versus time curve when administered once nightly at a strength of 4.5g approximately two hours after a standardized evening meal substantially as depicted in <figref idref="f0011">Figure 22</figref>.

0042In a thirteenth principal embodiment, the invention provides a modified release formulation of gamma-hydroxybutyrate, preferably comprising immediate release and modified release portions, that yields a dissolution profile substantially as depicted in <figref idref="f0004">Figure 7 and Figure 8</figref>.

0043In a fourteenth principal embodiment, the invention provides a modified release formulation of gamma-hydroxybutyrate, preferably comprising immediate release and modified release portions, that yields a dissolution profile substantially as depicted in <figref idref="f0010">Figure 20</figref> and <figref idref="f0011">Figure 21</figref>.

0044In a fifteenth principal embodiment, the invention provides a modified release formulation of gamma-hydroxybutyrate comprising immediate release and modified release portions, wherein said modified release portion yields a dissolution profile substantially as depicted in <figref idref="f0002">Figure 3</figref> or <figref idref="f0008">Figure 16</figref>.

0045In a sixteenth principal embodiment, the invention provides a modified release formulation of gamma-hydroxybutyrate, comprising immediate release and modified release portions that yields a dissolution profile between the minimum and maximum values depicted in <figref idref="f0013">Figure 25 and Figure 26</figref>.

0046In a seventeenth principal embodiment, the invention provides a modified release formulation of gamma-hydroxybutyrate, comprising immediate release and modified release portions that yields a dissolution profile between the minimum and maximum values depicted in <figref idref="f0014">Figure 27 and Figure 28</figref>.

0047In an eighteenth principal embodiment, the invention provides a modified release formulation of gamma-hydroxybutyrate yielding a dissolution profile substantially as shown in any one of <figref idref="f0015 f0016 f0017 f0018 f0019 f0020 f0021 f0022 f0023 f0024 f0025 f0026 f0027 f0028 f0029 f0030 f0031 f0032 f0033 f0034 f0035 f0036 f0037 f0038 f0039 f0040 f0041 f0042 f0043 f0044 f0045">Figures 29 through 89</figref>.

0048A nineteenth principal embodiment of the present invention provides a modified release formulation of gamma-hydroxybutyrate, preferably comprising immediate release and modified release portions, that yields a plasma concentration versus time curve when administered once nightly at a strength of 4.5 g, 7.5 g or 9.0 g approximately two hours after a standardized evening meal substantially as depicted in <figref idref="f0046">Figure 90</figref> for the corresponding strength.

0049A twentieth principal embodiment of the present invention provides a modified release formulation of gamma-hydroxybutyrate, preferably comprising immediate release and modified release portions that yields a dissolution profile between the minimum and maximum values depicted in <figref idref="f0013">Figure 26</figref> and <figref idref="f0014">Figure 28</figref>.

0050Still further embodiments relate to methods of using the formulations of the present invention to treat narcolepsy and associated disorders and symptoms, and to physical aspects of the formulations of the present invention. Additional principal embodiments and sub-embodiments thereto will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The embodiments and advantages of the invention will be realized and attained by means of the elements and combinations particularly pointed out in the appended claims. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention, as claimed.

DESCRIPTION OF THE FIGURES

0051The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate several embodiments of the invention and together with the description serve to explain the principles of the invention. <ul id="ul0001" list-style="none" compact="compact"><li><figref idref="f0001">Figure 1</figref> depicts the qualitative and quantitative structure of the immediate release (IR) and modified release (MR) microparticles of gamma-hydroxybutyrate of Example 1.</li><li><figref idref="f0001">Figure 2</figref> plots a time release dissolution profile of IR microparticles of gamma-hydroxybutyrate of Example 1 (◆) and 1bis <b>(■)</b> in a 0.1N HCl dissolution medium.</li><li><figref idref="f0002">Figure 3</figref> plots a time release dissolution profile of MR microparticles of gamma-hydroxybutyrate of Example 1 in two sequential dissolution media (0.1 N HCl/phosphate buffer pH 6.8).</li><li><figref idref="f0002">Figure 4</figref> plots a time release dissolution profile of MR microparticles (▲ symbols) of Example 1 in two sequential dissolution media (0.1 N HCl / phosphate buffer pH 6.8), overlaid against dissolution profile described in <figref idref="f0002">figure 3</figref> of <patcit id="pcit0009" dnum="US8193211B"><text>US 8,193,211</text></patcit> (● symbols).</li><li><figref idref="f0003">Figure 5</figref> plots a time release dissolution profile of the finished formulation of Example 1 in deionized water.</li><li><figref idref="f0003">Figure 6</figref> plots a time release dissolution profile of the finished composition of Example 1 in deionized water (▲ symbols), overlaid against dissolution profile described in <figref idref="f0001">figure 2</figref> of <patcit id="pcit0010" dnum="US20120076865A"><text>USP 2012/0076865</text></patcit>(● symbols).</li><li><figref idref="f0004">Figure 7</figref> plots time release dissolution profiles in 0.1N HCl of four separate batches of finished compositions produced in accordance with Example 1 or Example 1bis.</li><li><figref idref="f0004">Figure 8</figref> plots time release dissolution profiles in phosphate buffer pH 6.8 of four separate batches of finished compositions produced in accordance with Example 1or Example 1bis.</li><li><figref idref="f0005">Figure 9</figref> plots time release dissolution profiles in 0.1N HCl of MR microparticles of gamma-hydroxybutyrate produced in accordance with Example 1 at 75rpm (■ symbols) and 100rpm (▲ symbols).</li><li><figref idref="f0005">Figure 10</figref> plots time release dissolution profiles in 0.1N HCl of finished composition produced in accordance with Example 1 performed with paddle rotation speed set at 75rpm (■ symbols) and 100rpm (▲ symbols).</li><li><figref idref="f0006">Figure 11</figref> plots the mean + SD (standard deviation) plasma gamma-hydroxybutyrate concentrations (microgram/mL) versus time for two different modified release formulations of gamma-hydroxybutyrate tested in vivo according to the methods of Example 3. Time profiles are given for a 4.5 g dose of the finished composition of Example 1bis administered once (● symbols) (N=26) and a 4.5 g dose of Xyrem^® administered in two divided doses ( - symbols) (N=15).</li><li><figref idref="f0006">Figure 12</figref> plots the mean + SD (standard deviation) plasma gamma-hydroxybutyrate concentrations (microgram/mL) versus time after a Single Oral Administration of 4.5 g (● symbols) and 6 g (▲ symbols) of finished composition of Example 1bis in the same 7 subjects tested in vivo according to the methods of Example 3.</li><li><figref idref="f0007">Figure 13</figref> plots the mean + SD (standard deviation) plasma gamma-hydroxybutyrate concentrations (microgram/mL) versus time of three separate doses of finished composition prepared according to Example 1bis tested in vivo according to the methods of Example 3. Mean time profiles are given for a single oral administration of 4.5 g (N=26) (●), 6.0 g (N=19) <b>(A) or</b> 7.5g (■) doses (N=11).</li><li><figref idref="f0007">Figure 14</figref> plots the mean plasma gamma-hydroxybutyrate Concentrations (microgram/mL) of a Single dose of 7.5g (■) of finished composition prepared according to Example 1bis compared to 2 x 4.5 g Xyrem^® post-fed (Source NDA 21-196 review).</li><li><figref idref="f0008">Figure 15</figref> depicts the qualitative and quantitative structure of the immediate release (IR) and modified release (MR) microparticles of gamma-hydroxybutyrate of Example 4.</li><li><figref idref="f0008">Figure 16</figref> plots a time release dissolution profile of MR microparticles of gamma-hydroxybutyrate of Example 4 in two sequential dissolution media (0.1 N HCl and phosphate buffer pH 6.8).</li><li><figref idref="f0009">Figure 17</figref> plots a time release dissolution profile of MR microparticles (A symbols) of Example 4 in two sequential dissolution media (0.1 N HCl and phosphate buffer pH 6.8), overlaid against dissolution profile described in <figref idref="f0002">figure 3</figref> of <patcit id="pcit0011" dnum="US8193211B"><text>US 8,193,211</text></patcit> (● symbols).</li><li><figref idref="f0009">Figure 18</figref> plots a time release dissolution profile of the finished composition of Example 4 in deionized water.</li><li><figref idref="f0010">Figure 19</figref> plots a time release dissolution profile of the finished composition of Example 4 in deionized water (● symbols), overlaid against dissolution profile described in <figref idref="f0001">figure 2</figref> of <patcit id="pcit0012" dnum="US20120076865A"><text>USP 2012/0076865</text></patcit> (▲ symbols).</li><li><figref idref="f0010">Figure 20</figref> plots time release dissolution profiles in 0.1N HCl of three separate batches of finished compositions produced in accordance with Example 4 or 4bis.</li><li><figref idref="f0011">Figure 21</figref> plots a time release dissolution profile in phosphate buffer pH 6.8 of a finished composition produced in accordance with Example 4.</li><li><figref idref="f0011">Figure 22</figref> plots mean plasma gamma-hydroxybutyrate concentration (microgram/mL) time profiles after a Single Dose of 4.5g (■) of finished composition of Example 4bis, N=15 compared to 2 x 2.25 g Xyrem^® post fed, N=15.</li><li><figref idref="f0012">Figure 23</figref> depicts the qualitative and quantitative structure of the immediate release (IR) and modified release (MR) microparticles of gamma-hydroxybutyrate of Example 7.</li><li><figref idref="f0012">Figure 24</figref> plots a time release dissolution profile of MR microparticles of gamma-hydroxybutyrate of Example 7 (▲ symbols) in two sequential dissolution media (0.1 N HCl and phosphate buffer pH 6.8), overlaid against dissolution profile described in <figref idref="f0002">figure 3</figref> of <patcit id="pcit0013" dnum="US8193211B"><text>US 8,193,211</text></patcit> (● symbols).</li><li><figref idref="f0013">Figure 25</figref> plots the Min (■) and Max (▲) values of a preferred dissolution profile in 0.1N HCl of finished composition according to the invention.</li><li><figref idref="f0013">Figure 26</figref> plots the Min (■) and Max (▲) values of a preferred dissolution profile in phosphate buffer pH 6.8 of finished composition according to the invention.</li><li><figref idref="f0014">Figure 27</figref> plots the Min (■) and Max (▲) values of another preferred dissolution profile in phosphate buffer pH 6.8 of finished composition according to the invention.</li><li><figref idref="f0014">Figure 28</figref> plots the Min (■) and Max (▲) values of another preferred dissolution profile in 0.1N HCl of finished composition according to the invention.</li><li><figref idref="f0015">Figure 29</figref> depicts a dissolution profile determined in 0.1N HCl using a USP apparatus 2 for the formulation of Example 9.1 5 minutes and 15 minutes after reconstitution in water.</li><li><figref idref="f0015">Figure 30</figref> depicts a dissolution profile determined in 0.1N HCl using a USP apparatus 2 for the formulation of Example 9.2 5 minutes and 15 minutes after reconstitution in water.</li><li><figref idref="f0016">Figure 31</figref> depicts a dissolution profile determined in 0.1N HCl using a USP apparatus 2 for the formulation of Example 9.3 5 minutes and 15 minutes after reconstitution in water.</li><li><figref idref="f0016">Figure 32</figref> depicts the dissolution profile determined in 0.1N HCl using a USP apparatus 2 of a 9g dose of the formulation of Example 10 with and without rinsing.</li><li><figref idref="f0017">Figure 33</figref> depicts the dissolution profile of the MR portion of the formulation of Example 11a in 900ml of 0.1N HCl and pH 6.8 phosphate buffer (0.05M monobasic potassium phosphate solution - pH adjusted to 6.8 with 5N NaOH) using a USP apparatus 2.</li><li><figref idref="f0017">Figure 34</figref> depicts the dissolution profile of the formulation of Example 11a in 900ml of 0.1N HCl using a USP apparatus 2.</li><li><figref idref="f0018">Figure 35</figref> depicts the dissolution profile of the formulation of Example 11a in pH6.8 phosphate buffer (0.05M monobasic potassium phosphate solution - pH adjusted to 6.8 with 5N NaOH) using a USP apparatus 2.</li><li><figref idref="f0018">Figure 36</figref> depicts the dissolution profile of the MR portion of the formulation of Example 11b in 900ml of 0.1N HCl using a USP apparatus 2.</li><li><figref idref="f0019">Figure 37</figref> depicts the dissolution profile of the formulation of Example 11b in 900ml of 0.1N HCl using a USP apparatus 2.</li><li><figref idref="f0019">Figure 38</figref> depicts the dissolution profile of the formulation of Example 11b in pH6.8 phosphate buffer (0.05M monobasic potassium phosphate solution - pH adjusted to 6.8 with 5N NaOH) using a USP apparatus 2.</li><li><figref idref="f0020">Figure 39</figref> depicts the dissolution profile of the formulation of Example 11c in 900ml of 0.1N HCl using a USP apparatus 2.</li><li><figref idref="f0020">Figure 40</figref> depicts the dissolution profile of the formulation of Example 11c in pH6.8 phosphate buffer (0.05M monobasic potassium phosphate solution - pH adjusted to 6.8 with 5N NaOH) using a USP apparatus 2.</li><li><figref idref="f0021">Figure 41</figref> depicts the dissolution profile of the MR portion of the formulation of Example 12a in 900ml of 0.1N HCl using a USP apparatus 2.</li><li><figref idref="f0021">Figure 42</figref> depicts the dissolution profile of the formulation of Example 12a using a USP apparatus 2 in 0.1N HCl.</li><li><figref idref="f0022">Figure 43</figref> depicts the dissolution profile of the formulation of Example 12b in 900ml of 0.1N HCl using a USP apparatus 2.</li><li><figref idref="f0022">Figure 44</figref> depicts the dissolution profile of the formulation of Example 12b in pH6.8 phosphate buffer (0.05M monobasic potassium phosphate solution - pH adjusted to 6.8 with 5N NaOH) using a USP apparatus 2.</li><li><figref idref="f0023">Figure 45</figref> depicts the dissolution profile of the MR portion of the formulation of Example 13 in 900ml of 0.1N HCl and pH 6.8 phosphate buffer (0.05M monobasic potassium phosphate solution - pH adjusted to 6.8 with 5N NaOH) using a USP apparatus 2.</li><li><figref idref="f0023">Figure 46</figref> depicts the dissolution profile of the formulation of Example 13 in 900ml of 0.1N HCl using a USP apparatus 2.</li><li><figref idref="f0024">Figure 47</figref> depicts the dissolution profile of the formulation of Example 13 in pH6.8 phosphate buffer (0.05M monobasic potassium phosphate solution - pH adjusted to 6.8 with 5N NaOH) using a USP apparatus 2.</li><li><figref idref="f0024">Figure 48</figref> depicts the dissolution profile of the MR portion of the formulation of Example 14 in 900ml of 0.1N HCl and pH 6.8 phosphate buffer (0.05M monobasic potassium phosphate solution - pH adjusted to 6.8 with 5N NaOH) using a USP apparatus 2.</li><li><figref idref="f0025">Figure 49</figref> depicts the dissolution profile of the formulation of Example 14 in 900ml of 0.1N HCl using a USP apparatus 2.</li><li><figref idref="f0025">Figure 50</figref> depicts the dissolution profile of the formulation of Example 14 in pH6.8 phosphate buffer (0.05M monobasic potassium phosphate solution - pH adjusted to 6.8 with 5N NaOH) using a USP apparatus 2.</li><li><figref idref="f0026">Figure 51</figref> depicts the dissolution profile of the MR portion of the formulation of Example 15a (coating weight 35%) in 900ml of 0.1N HCl using a USP apparatus 2.</li><li><figref idref="f0026">Figure 52</figref> depicts the dissolution profile of the MR portion of the formulation of Example 15a (coating weight 50%) in 900ml of 0.1N HCl using a USP apparatus 2.</li><li><figref idref="f0027">Figure 53</figref> depicts the dissolution profile of the formulation of Example 15a in 900ml of 0.1N HCl using a USP apparatus 2.</li><li><figref idref="f0027">Figure 54</figref> depicts the dissolution profile of the MR portion of the formulation of Example 15b in 900ml of 0.1N HCl and pH 6.8 phosphate buffer (0.05M monobasic potassium phosphate solution - pH adjusted to 6.8 with 5N NaOH) using a USP apparatus 2.</li><li><figref idref="f0028">Figure 55</figref> depicts the dissolution profile of the formulation of Example 15b in 900ml of 0.1N HCl using a USP apparatus 2.</li><li><figref idref="f0028">Figure 56</figref> depicts the dissolution profile of the formulation of Example 15b in pH6.8 phosphate buffer (0.05M monobasic potassium phosphate solution - pH adjusted to 6.8 with 5N NaOH) using a USP apparatus 2.</li><li><figref idref="f0029">Figure 57</figref> depicts the dissolution profile of the MR portion of the formulation of Example 15c in 900ml of 0.1N HCl using a USP apparatus 2.</li><li><figref idref="f0029">Figure 58</figref> depicts the dissolution profile of the formulation of Example 15c in 900ml of 0.1N HCl using a USP apparatus 2.</li><li><figref idref="f0030">Figure 59</figref> depicts the dissolution profile of the formulation of Example 15c in pH6.8 phosphate buffer (0.05M monobasic potassium phosphate solution - pH adjusted to 6.8 with 5N NaOH) using a USP apparatus 2.</li><li><figref idref="f0030">Figure 60</figref> depicts the dissolution profile of the MR portion of the formulation of Example 15d in 900ml of 0.1N HCl and pH 6.8 phosphate buffer (0.05M monobasic potassium phosphate solution - pH adjusted to 6.8 with 5N NaOH) using a USP apparatus 2.</li><li><figref idref="f0031">Figure 61</figref> depicts the dissolution profile of the formulation of Example 15d in 900ml of 0.1N HCl using a USP apparatus 2.</li><li><figref idref="f0031">Figure 62</figref> depicts the dissolution profile of the formulation of Example 15d in pH6.8 phosphate buffer (0.05M monobasic potassium phosphate solution - pH adjusted to 6.8 with 5N NaOH) using a USP apparatus 2.</li><li><figref idref="f0032">Figure 63</figref> depicts the dissolution profile of the MR portion of the formulation of Example 16a in 900ml of 0.1N HCl and pH 6.8 phosphate buffer (0.05M monobasic potassium phosphate solution - pH adjusted to 6.8 with 5N NaOH) using a USP apparatus 2.</li><li><figref idref="f0032">Figure 64</figref> depicts the dissolution profile of the formulation of Example 16a in 900ml of 0.1N HCl using a USP apparatus 2.</li><li><figref idref="f0033">Figure 65</figref> depicts the dissolution profile of the formulation of Example 16a in pH6.8 phosphate buffer (0.05M monobasic potassium phosphate solution - pH adjusted to 6.8 with 5N NaOH) using a USP apparatus 2.</li><li><figref idref="f0033">Figure 66</figref> depicts the dissolution profile of the MR portion of the formulation of Example 16b in 900ml of 0.1N HCl and pH 6.8 phosphate buffer (0.05M monobasic potassium phosphate solution - pH adjusted to 6.8 with 5N NaOH) using a USP apparatus 2.</li><li><figref idref="f0034">Figure 67</figref> depicts the dissolution profile of the formulation of Example 16b in 900ml of 0.1N HCl using a USP apparatus 2.</li><li><figref idref="f0034">Figure 68</figref> depicts the dissolution profile of the formulation of Example 16b in pH6.8 phosphate buffer (0.05M monobasic potassium phosphate solution - pH adjusted to 6.8 with 5N NaOH) using a USP apparatus 2.</li><li><figref idref="f0035">Figure 69</figref> depicts the dissolution profile of the MR portion of the formulation of Example 16c in 900ml of 0.1N HCl and pH 6.8 phosphate buffer (0.05M monobasic potassium phosphate solution - pH adjusted to 6.8 with 5N NaOH) using a USP apparatus 2.</li><li><figref idref="f0035">Figure 70</figref> depicts the dissolution profile of the formulation of Example 16c in 900ml of 0.1N HCl using a USP apparatus 2.</li><li><figref idref="f0036">Figure 71</figref> depicts the dissolution profile of the formulation of Example 16c in pH6.8 phosphate buffer (0.05M monobasic potassium phosphate solution - pH adjusted to 6.8 with 5N NaOH) using a USP apparatus 2.</li><li><figref idref="f0036">Figure 72</figref> depicts the dissolution profile of the MR portion of the formulation of Example 16d in 900ml of 0.1N HCl using a USP apparatus 2.</li><li><figref idref="f0037">Figure 73</figref> depicts the dissolution profile of the MR portion of the formulation of Example 17a in 900ml of 0.1N HCl using a USP apparatus 2.</li><li><figref idref="f0037">Figure 74</figref> depicts the dissolution profile of the formulation of Example 17a in 900ml of 0.1N HCl using a USP apparatus 2.</li><li><figref idref="f0038">Figure 75</figref> depicts the dissolution profile of the formulation of Example 17a in pH6.8 phosphate buffer (0.05M monobasic potassium phosphate solution - pH adjusted to 6.8 with 5N NaOH) using a USP apparatus 2.</li><li><figref idref="f0038">Figure 76</figref> depicts the dissolution profile of the MR portion of the formulation of Example 17b in 900ml of 0.1N HCl and pH 6.8 phosphate buffer (0.05M monobasic potassium phosphate solution - pH adjusted to 6.8 with 5N NaOH) using a USP apparatus 2.</li><li><figref idref="f0039">Figure 77</figref> depicts the dissolution profile of the formulation of Example 17b in 900ml of 0.1N HCl using a USP apparatus 2.</li><li><figref idref="f0039">Figure 78</figref> depicts the dissolution profile of the formulation of Example 17b in pH6.8 phosphate buffer (0.05M monobasic potassium phosphate solution - pH adjusted to 6.8 with 5N NaOH) using a USP apparatus 2.</li><li><figref idref="f0040">Figure 79</figref> depicts the dissolution profile of the MR portion of the formulation of Example 17c in 900ml of 0.1N HCl and pH 6.8 phosphate buffer (0.05M monobasic potassium phosphate solution - pH adjusted to 6.8 with 5N NaOH) using a USP apparatus 2.</li><li><figref idref="f0040">Figure 80</figref> depicts the dissolution profile of the formulation of Example 17c in 900ml of 0.1N HCl using a USP apparatus 2.</li><li><figref idref="f0041">Figure 81</figref> depicts the dissolution profile of the formulation of Example 17c in pH6.8 phosphate buffer (0.05M monobasic potassium phosphate solution - pH adjusted to 6.8 with 5N NaOH) using a USP apparatus 2.</li><li><figref idref="f0041">Figure 82</figref> depicts a preferred dissolution profile of sodium oxybate MR microparticles in 900 ml 0.1N HCl using a USP apparatus 2 at 75 rpm.</li><li><figref idref="f0042">Figure 83</figref> depicts a preferred dissolution profile of sodium oxybate MR microparticles in 900 ml pH 6.8 phosphate buffer (0.05M monobasic potassium phosphate solution - pH adjusted to 6.8 with 5N NaOH) using a USP apparatus 2 at 75 rpm.</li><li><figref idref="f0042">Figure 84</figref> depicts a preferred dissolution profile of a sodium oxybate finished formulation comprising IR and MR microparticles in 900 ml 0.1N HCl using a USP apparatus 2 at 75 rpm.</li><li><figref idref="f0043">Figure 85</figref> depicts a preferred dissolution profile of a sodium oxybate finished formulation comprising IR and MR microparticles in 900 ml pH 6.8 phosphate buffer (0.05M monobasic potassium phosphate solution - pH adjusted to 6.8 with 5N NaOH) using a USP apparatus 2 at 75 rpm.</li><li><figref idref="f0043">Figure 86</figref> is a dissolution profile in 0.1N HCl of two separate batches of the sodium oxybate MR microparticles present in the finished composition of Example 18.</li><li><figref idref="f0044">Figure 87</figref> is a dissolution profile in phosphate buffer pH 6.8 of two separate batches of the sodium oxybate MR microparticles present in the finished composition of Example 18.</li><li><figref idref="f0044">Figure 88</figref> is a dissolution profile in 0.1N HCl of two unit doses of 3g (▲ symbols) and 4.5g (● symbols) of the finished composition of Example 18.</li><li><figref idref="f0045">Figure 89</figref> is a dissolution profile in phosphate buffer pH 6.8 of two unit doses of 3g (▲ symbols) and 4.5g (● symbols) of the finished composition of Example 18.</li><li><figref idref="f0046">Figure 90</figref> plots mean plasma gamma-hydroxybutyrate concentrations (microgram/mL) + SD - time profiles after a single oral administration of 4.5g (● symbols),7.5g (■ symbols) and 9g (A symbols) of the finished composition of Example 18.</li></ul>

DETAILED DESCRIPTION OF THE INVENTION

0052The present invention may be understood more readily by reference to the following detailed description of preferred embodiments of the invention and the Examples included therein.

Definitions and Use of Terms

0053Wherever an analysis or test is required to understand a given property or characteristic recited herein, it will be understood that the analysis or test is performed in accordance with applicable guidances, draft guidances, regulations and monographs of the United States Food and Drug Administration ("FDA") and United States Pharmacopoeia ("USP") applicable to drug products in the United States in force as of November 1, 2015 unless otherwise specified. Clinical endpoints can be judged with reference to standards adopted by the American Academy of Sleep Medicine, including standards published at C Iber, S Ancoli-Israel, A Chesson, SF Quan. The AASM Manual for the Scoring of Sleep and Associated Events. Westchester, IL: American Academy of Sleep Medicine; 2007.

0054When a pharmacokinetic comparison is made between a formulation described or claimed herein and a reference product, it will be understood that the comparison is preferably performed in a suitable designed cross-over trial, although it will also be understood that a cross-over trial is not required unless specifically stated. It will also be understood that the comparison can be made either directly or indirectly. For example, even if a formulation has not been tested directly against a reference formulation, it can still satisfy a comparison to the reference formulation if it has been tested against a different formulation, and the comparison with the reference formulation can be deduced therefrom.

0055As used in this specification and in the claims which follow, the singular forms "a," "an" and "the" include plural referents unless the context dictates otherwise. Thus, for example, reference to "an ingredient" includes mixtures of ingredients, reference to "an active pharmaceutical agent" includes more than one active pharmaceutical agent, and the like.

0056"Bioavailability" means the rate and extent to which the active ingredient or active moiety is absorbed from a drug product and becomes available at the site of action.

0057"Relative bioavailability" or "Rel BA" or "RBA" means the percentage of mean AUC_int of the tested product relative to the mean AUC_inf of the reference product. Unless otherwise specified, relative bioavailability refers to the percentage of the mean AUC_inf observed for a full dose of the test product relative to the mean AUC_inf observed for two ½-doses of an immediate release liquid solution administered four hours apart.

0058"Bioequivalence" means the absence of a significant difference in the rate and extent to which the active ingredient or active moiety in pharmaceutical equivalents or pharmaceutical alternatives become available at the site of drug action when administered at the same molar dose under similar conditions in an appropriately designed study.

0059When ranges are given by specifying the lower end of a range separately from the upper end of the range, it will be understood that the range can be defined by selectively combining any one of the lower end variables with any one of the upper end variables that is mathematically and physically possible. Thus, for example, if a formulation may contain from 1 to 10 weight parts of a particular ingredient, or 2 to 8 parts of a particular ingredient, it will be understood that the formulation may also contain from 2 to 10 parts of the ingredient. In like manner, if a formulation may contain greater than 1 or 2 weight parts of an ingredient and up to 10 or 9 weight parts ofthe ingredient, it will be understood that the formulation may contain 1-10 weight parts of the ingredient, 2-9 weight parts of the ingredient, etc. unless otherwise specified, the boundaries of the range (lower and upper ends of the range) are included in the claimed range.

0060In like manner, when various sub-embodiments of a senior (i.e. principal) embodiment are described herein, it will be understood that the sub-embodiments for the senior embodiment can be combined to define another sub-embodiment. Thus, for example, when a principal embodiment includes sub-embodiments 1, 2 and 3, it will be understood that the principal embodiment can be further limited by any one of sub-embodiments 1, 2 and 3, or any combination of sub-embodiments 1, 2 and 3 that is mathematically and physically possible. In like manner, it will be understood that the principal embodiments described herein can be combined in any manner that is mathematically and physically possible, and that the invention extends to such combinations.

0061When used herein the term "about" or "substantially" or "approximately" will compensate for variability allowed for in the pharmaceutical industry and inherent in pharmaceutical products, such as differences in product strength due to manufacturing variation and time-induced product degradation. The term allows for any variation which in the practice of pharmaceuticals would allow the product being evaluated to be considered bioequivalent to the recited strength, as described in FDA's March 2003 Guidance for Industry on BIOAVAILABILITY AND BIOEQUIVALENCE STUDIES FOR ORALLY ADMINISTERED DRUG PRODUCTS - GENERAL CONSIDERATIONS.

0062When used herein the term "gamma-hydroxybutyrate" or GHB, unless otherwise specified, refers to the free base of gamma hydroxy-butyrate, a pharmaceutically acceptable salt of gamma-hydroxybutyric acid, and combinations thereof, their hydrates, solvates, complexes or tautomers forms. Gamma-hydroxybutyric acid salts can be selected from the sodium salt of gamma-hydroxybutyric acid or sodium oxybate, the potassium salt of gamma-hydroxybutyric acid, the magnesium salt of gamma-hydroxybutyric acid, the calcium salt of gamma-hydroxybutyric acid, the lithium salt of gamma-hydroxybutyric, the tetra ammonium salt of gamma-hydroxybutyric acid or any other pharmaceutically acceptable salt forms of gamma-hydroxybutyric acid.

0063"Pharmaceutically acceptable" means that which is useful in preparing a pharmaceutical composition that is generally safe, non-toxic and neither biologically nor otherwise undesirable and includes that which is acceptable for veterinary use as well as human pharmaceutical use. The term "formulation" or "composition" refers to the quantitative and qualitative characteristics of a drug product or dosage form prepared in accordance with the current invention.

0064As used herein the doses and strengths of gamma-hydroxybutyrate are expressed in equivalent-gram (g) weights of sodium oxybate unless stated expressly to the contrary. Thus, when considering a dose of gamma-hydroxybutyrate other than the sodium salt of gamma-hydroxybutyrate, one must convert the recited dose or strength from sodium oxybate to the gamma-hydroxybutyrate under evaluation. Thus, if an embodiment is said to provide a 4.5g dose of gamma-hydroxybutyrate, because the form of gamma-hydroxybutyrate is not specified, it will be understood that the dose encompasses a 4.5g dose of sodium oxybate, a 5.1g dose of potassium gamma-hydroxybutyrate (assuming a 126.09 g/mol MW for sodium oxybate and a 142.20 g/mol MW for potassium gamma-hydroxybutyrate), and a 3.7g dose of the free base (assuming a 126.09 g/mol MW for sodium oxybate and a 104.1 g/mol MW for the free base of gamma-hydroxybutyrate), or by the weight of any mixture of salts of gamma-hydroxybutyric acid that provides the same amount of GHB as 4.5g of sodium oxybate.

0065As used herein "microparticle" means any discreet particle of solid material. The particle can be made of a single material or have a complex structure with core and shells and be made of several materials. The terms "microparticle", "particle", "microspheres" or "pellet" are interchangeable and have the same meaning. Unless otherwise specified, the microparticle has no particular particle size or diameter and is not limited to particles with volume mean diameter D(4,3) below 1mm.

0066As used herein, the "volume mean diameter D(4,3)" is calculated according to the following formula: <maths id="math0001"><math display="block"><mi mathvariant="normal">D</mi><mfenced><mn>4</mn><mn>3</mn></mfenced><mo>=</mo><mi mathvariant="normal">Σ</mi><mfenced><msub><msup><mi mathvariant="normal">d</mi><mn>4</mn></msup><mi mathvariant="normal">i</mi></msub><mo>.</mo><msub><mi mathvariant="normal">n</mi><mi mathvariant="normal">i</mi></msub></mfenced><mo>/</mo><mi mathvariant="normal">Σ</mi><mfenced><msub><msup><mi mathvariant="normal">d</mi><mn>3</mn></msup><mi mathvariant="normal">i</mi></msub><mo>.</mo><msub><mi mathvariant="normal">n</mi><mi mathvariant="normal">i</mi></msub></mfenced></math><img file="EP4623907A2_D0004.tif" /></maths> wherein the diameter d of a given particle is the diameter of a hard sphere having the same volume as the volume of that particle.

0067As used herein, the terms "finished composition", "finished formulation" or "formulation" are interchangeable and designate the modified release formulation of gamma-hydroxybutyrate preferably comprising modified release microparticles of gamma-hydroxybutyrate, immediate release microparticles of gamma-hydroxybutyrate, and any other excipients.

0068As used herein and in the claims that follow, an "immediate release (IR) portion" of a formulation includes physically discreet portions of a formulation, mechanistically discreet portions of a formulation, and pharmacokinetically discreet portions of a formulation that lend to or support a defined IR pharmacokinetic characteristic. Thus, for example, any formulation that releases active ingredient at the rate and extent required of the immediate release portion of the formulations of the present invention includes an "immediate release portion," even if the immediate release portion is physically integrated in what might otherwise be considered an extended release formulation. Thus, the IR portion can be structurally discreet or structurally indiscreet from (i.e. integrated with) the MR portion. In a preferred embodiment, the IR portion and MR portion are provided as particles, and in an even more preferred subembodiment the IR portion and MR portion are provided as particles discreet from each other.

0069Thus, in an embodiment of the present invention, the modified release portion and the immediate release portion comprise structurally discreet modified release particles and immediate release particles. In another embodiment of the invention, the modified release portion and the immediate release portion comprise structurally indiscreet particles.

0070As used here in, "immediate release formulation" or "immediate release portion" refers to a composition that releases at least 80% of its gamma-hydroxybutyrate in 1 hour when tested in a dissolution apparatus 2 according to USP 38 <711> in a 0.1N HCl dissolution medium at a temperature of 37° C and a paddle speed of 75 rpm.

0071In like manner, a "modified-release (MR) portion" includes that portion of a formulation or dosage form that lends to or supports a particular MR pharmacokinetic characteristic, regardless of the physical formulation in which the MR portion is integrated. The modified release drug delivery systems are designed to deliver drugs at a specific time or over a period of time after administration, or at a specific location in the body. The USP defines a modified release system as one in which the time course or location of drug release or both, are chosen to accomplish objectives of therapeutic effectiveness or convenience not fulfilled by conventional IR dosage forms. More specifically, MR solid oral dosage forms include extended release (ER) and delayed- release (DR) products. A DR product is one that releases a drug all at once at a time other than promptly after administration. Typically, coatings (e.g., enteric coatings) are used to delay the release of the drug substance until the dosage form has passed through the acidic medium of the stomach. An ER product is formulated to make the drug available over an extended period after ingestion, thus allowing a reduction in dosing frequency compared to a drug presented as a conventional dosage form, e.g. a solution or an immediate release dosage form. For oral applications, the term "extended-release" is usually interchangeable with "sustained-release", "prolonged-release" or "controlled-release".

0072Traditionally, extended-release systems provided constant drug release to maintain a steady concentration of drug. For some drugs, however, zero-order delivery may not be optimal and more complex and sophisticated systems have been developed to provide multiphase delivery. One can distinguish among four categories of oral MR delivery systems: (1) delayed- release using enteric coatings, (2) site-specific or timed release (e.g. for colonic delivery), (3) extended-release (e.g., zero-order, first-order, biphasic release, etc.), and (4), programmed release (e.g., pulsatile, delayed extended release, etc.) See <nplcit id="ncit0002" npl-type="s"><text>Modified Oral Drug Delivery Systems at page 34 in Gibaldi's DRUG DELIVERY SYSTEMS IN PHARMACEUTICAL CARE, AMERICAN SOCIETY OF HEALTH-SYSTEM PHARMACISTS, 2007</text></nplcit> and <nplcit id="ncit0003" npl-type="b"><text>Rational Design of Oral Modified-release Drug Delivery Systems at page 469 in DEVELOPING SOLID ORAL DOSAGE FORMS: PHARMACEUTICAL THEORY AND PRACTICE, Academic Press, Elsevier, 2009</text></nplcit>. As used herein, "modified release formulation" or "modified release portion" in one embodiment refers to a composition that releases its gamma-hydroxybutyrate according a multiphase delivery that is comprised in the fourth class of MR products, e.g. delayed extended release. As such it differs from the delayed release products that are classified in the first class of MR products.

0073As used herein the terms "coating", "coating layer," "coating film," "film coating" and like terms are interchangeable and have the same meaning. The terms refer to the coating applied to a particle comprising the gamma-hydroxybutyrate that controls the modified release of the gamma-hydroxybutyrate.

0074In all pharmacokinetic testing described herein, unless otherwise stated, the dosage form, or the initial dosage form if the dosing regimen calls for more than one administration, is administered approximately two hours after consumption of a standardized dinner consisting of 25.5% fat, 19.6% protein, and 54.9% carbohydrates.

0075A "similar PK profile" or "comparable bioavailability" means that the mean AUC_inf of a test product is from 80% to 125% of the mean AUC_inf of a reference product in a suitably designed cross-over trial, and that the mean plasma concentration at 8 hours (C_8h) of the test product is from 50% to 130% of the mean plasma concentration at 8 hours (C_8h) of the reference product.

0076Type 1 Narcolepsy (NT1) refers to narcolepsy characterized by excessive daytime sleepiness ("EDS") and cataplexy. Type 2 Narcolepsy (NT2) refers to narcolepsy characterized by excessive daytime sleepiness without cataplexy. A diagnosis of narcolepsy (with or without cataplexy) can be confirmed by one or a combination of (i) an overnight polysomnogram (PSG) and a Multiple Sleep Latency Test (MSLT) performed within the last 2 years, (ii) a full documentary evidence confirming diagnosis from the PSG and MSLT from a sleep laboratory must be made available, (iii) current symptoms of narcolepsy including: current complaint of EDS for the last 3 months (ESS greater than 10), (iv) mean MWT less than 8 minutes, (v) mean number of cataplexy events of 8 per week on baseline Sleep/Cataplexy Diary, and/or (vi) presence of cataplexy for the last 3 months and 28 events per week during screening period.

0077Unless otherwise specified herein, percentages, ratios and numeric values recited herein are based on weight; averages and means are arithmetic means; all pharmacokinetic measurements based on the measurement of bodily fluids are based on plasma concentrations.

0078It will be understood, when defining a composition by its pharmacokinetic or dissolution properties herein, that the formulation can in the alternative be defined as "means for" achieving the recited pharmacokinetic or dissolution properties. Thus, a formulation in which the modified release portion releases less than 20% of its gamma-hydroxybutyrate at one hour can instead be defined as a formulation comprising "means for" or "modified release means for" releasing less than 20% of its gamma-hydroxybutyrate at one hour. It will be further understood that the preferred structures for achieving the recited pharmacokinetic or dissolution properties are the structures described in the examples hereof that accomplish the recited pharmacokinetic or dissolution properties.

Discussion of Principal Embodiments

0079The invention can be described in terms of principal embodiments, which in turn can be recombined to make other principal embodiments, and limited by sub-embodiments to make other principal embodiments.

0080A first principal embodiment of the present invention provides a modified release formulation of gamma-hydroxybutyrate, preferably comprising immediate release and modified release portions, wherein a 7.5 g dose of the formulation has been shown to achieve a mean AUC_inf of greater than 245, 300, 325, 340, 375, 400, 425, or 450 hrxmicrogram/mL, most preferably greater than 340 hrmicrogram/mL.

0081A second principal embodiment of the present invention provides a modified release formulation of gamma-hydroxybutyrate, preferably comprising immediate release and modified release portions, wherein a 7.5 g dose of the formulation has been shown to achieve a mean AUC_inf of greater than 245, 265, 285, 300, 315, 325, 340, 350, 375, 400, 425, or 450 hr<img file="EP4623907A2_D0005.tif" /> microgram/mL, most preferably greater than 340 hrxmicrogram/mL, and a mean C_8h that is from 50% to 130%, from 60% to 130%, from 70% to 130%, from 75% to 125%, from 80% to 125%, from 80 to 120%, from 90% to 110%, from 50% to 95%, from 60% to 90%, most preferably from 60% to 90% or 60% to 130% of the mean C_8h provided by an equal dose of an immediate release liquid solution of sodium oxybate (e.g. Xyrem^®) administered at t₀ and t_4h in equally divided doses approximately two hours after a standardized evening meal.

0082A third principal embodiment of the present invention provides a modified release formulation of gamma-hydroxybutyrate, preferably comprising immediate release and modified release portions, wherein the formulation releases (a) at least 80% or 90% of its gamma-hydroxybutyrate at 3 hours, 2 hours, 1 hour, 0.5 hours, or 0.25 hours, preferably 1 hour, when tested in a dissolution apparatus 2 according to USP 38 <711> in 900 mL of 0.05M monobasic potassium phosphate buffer pH 6.8 at a temperature of 37° C and a paddle speed of 75 rpm, and (b) from 10 to 65%, from 15 to 60%, from 20 to 55%, from 25 to 55%, from 30 to 55%, from 35 to 55%, from 40 to 55%, from 40 to 60%, or from 45 to 55%, preferably from 40% to 60%, of its gamma-hydroxybutyrate at one hour and three hours when tested in a dissolution apparatus 2 according to USP 38 <711> in 900 mL of 0.1N hydrochloric acid at a temperature of 37°C and a paddle speed of 75 rpm.

0083A fourth principal embodiment of the present invention provides a modified release formulation of gamma-hydroxybutyrate, comprising immediate release and modified release portions, wherein (a) the formulation releases at least 80% or 90% of its gamma-hydroxybutyrate at 3 hours, 2 hours, 1 hour, 0.5 hours, or 0.25 hours, preferably 1 hour, when tested in a dissolution apparatus 2 according to USP 38 <711> in 900 mL of 0.05M monobasic potassium phosphate buffer pH 6.8 at a temperature of 37° C and a paddle speed of 75 rpm, (b) the formulation releases from 10 to 65%, from 15 to 60%, from 20 to 55%, from 25 to 55%, from 30 to 55%, from 35 to 55%, from 40 to 55%, from 40 to 60%, or from 45 to 55%, preferably from 40% to 60%, of its gamma-hydroxybutyrate at one hour and at three hours when tested in a dissolution apparatus 2 according to USP 38 <711> in 900 mL of 0.1N hydrochloric acid at a temperature of 37°C and a paddle speed of 75 rpm, and (c) the modified release portion preferably releases greater than 80% or 90% of its gamma-hydroxybutyrate at 3 hours in a dissolution test started in 750 mL of 0.1N hydrochloric acid for 2 hours then switched to 950 mL 0.05M monobasic potassium phosphate buffer adjusted to pH 6.8 at a temperature of 37°C and a paddle speed of 75 rpm.

0084A fifth principal embodiment of the present invention provides a modified release formulation of gamma-hydroxybutyrate, comprising immediate release and modified release portions, wherein (a) the formulation releases at least 80% or 90% of its gamma-hydroxybutyrate at 3 hours, 2 hours, 1 hour, 0.5 hours, or 0.25 hours, preferably 1 hour, when tested in a dissolution apparatus 2 according to USP 38 <711> in 900 mL of 0.05M monobasic potassium phosphate buffer pH 6.8 at a temperature of 37° C and a paddle speed of 75 rpm, (b) the formulation releases from 10 to 65%, from 15 to 60%, from 20 to 55%, from 25 to 55%, from 30 to 55%, from 35 to 55%, from 40 to 55%, from 40 to 60%, or from 45 to 55%, preferably from 40% to 60%, of its gamma-hydroxybutyrate at one hour and at three hours when tested in a dissolution apparatus 2 according to USP 38 <711> in 900 mL of 0.1N hydrochloric acid at a temperature of 37°C and a paddle speed of 75 rpm, (c) the formulation releases greater than 60%, 70%, or 80%, preferably greater than 80%, of its gamma-hydroxybutyrate at 10 hours when tested in a dissolution apparatus 2 according to USP 38 <711> in 900 mL of 0.1N hydrochloric acid at a temperature of 37°C and a paddle speed of 75 rpm, and (d) the modified release portion releases greater than 80% of its gamma-hydroxybutyrate at 3 hours in a dissolution test started in 750 mL of 0.1N hydrochloric acid for 2 hours then switched to 950 mL 0.05M monobasic potassium phosphate buffer adjusted to pH 6.8 at a temperature of 37°C and a paddle speed of 75 rpm.

0085A sixth principal embodiment of the present invention provides a modified release formulation of gamma-hydroxybutyrate, comprising immediate release and modified release portions, wherein (a) a 7.5 g dose of the formulation has been shown to achieve a mean AUC_inf of greater than 245, 300, 325, 340, 375, 400, 425, or 450 hr<img file="EP4623907A2_D0006.tif" /> microgram/mL, preferably 340 hr<img file="EP4623907A2_D0007.tif" /> microgram/mL, and a mean C_8h that is from 50% to 130%, from 60% to 130%, from 70% to 130%, from 75% to 125%, from 80% to 125%, from 80 to 120%, from 90% to 110%, from 50% to 95%, or from 60% to 90%, preferably from 60% to 90% or from 60% to 130%, of the mean C_8h provided by an equal dose of an immediate release liquid solution of gamma-hydroxybutyrate (e.g. Xyrem^®) administered at t₀ and t_4h in equally divided doses approximately two hours after a standardized evening meal, and (b) the formulation releases (i) at least 80% or 90% of its gamma-hydroxybutyrate at 3 hours, 2 hours, 1 hour, 0.5 hours, or 0.25 hours, preferably 1 hour, when tested in a dissolution apparatus 2 according to USP 38 <711> in 900 mL of 0.05M monobasic potassium phosphate buffer pH 6.8 at a temperature of 37° C and a paddle speed of 75 rpm, and (ii) from 10 to 65%, from 15 to 60%, from 20 to 55%, from 25 to 55%, from 30 to 55%, from 35 to 55%, from 40 to 55%, from 40 to 60%, or from 45 to 55%, preferably from 40% to 60%, of its gamma-hydroxybutyrate at one hour and three hours when tested in a dissolution apparatus 2 according to USP 38 <711> in 900 mL of 0.1N hydrochloric acid at a temperature of 37°C and a paddle speed of 75 rpm, and (c) the modified release portion releases greater than 80% of its gamma-hydroxybutyrate at 3 hours in a dissolution test started in 750 mL of 0.1N hydrochloric acid for 2 hours then switched to 950 mL 0.05M monobasic potassium phosphate buffer adjusted to pH 6.8 at a temperature of 37°C and a paddle speed of 75 rpm.

0086A seventh principal embodiment of the present invention provides a modified release formulation of gamma-hydroxybutyrate comprising immediate release and modified release portions, wherein: (a) said immediate release portion releases greater than 80% or 90% of its gamma-hydroxybutyrate at one hour when tested in a dissolution apparatus 2 according to USP 38 <711> in 900 mL of 0.1N hydrochloric acid at a temperature of 37°C and a paddle speed of 75 rpm; (b) said modified release portion releases less than 20% or 10% of its gamma-hydroxybutyrate at one hour when tested in a dissolution apparatus 2 according to USP 38 <711> in 900 mL of 0.1N hydrochloric acid at a temperature of 37°C and a paddle speed of 75 rpm; and (c) said modified release portion releases greater than 80% or 90% of its gamma-hydroxybutyrate at three hours, two hours or one hour, when tested in a dissolution apparatus 2 according to USP 38 <711> in 900 mL of 0.05M monobasic potassium phosphate buffer pH 6.8 at a temperature of 37° C and a paddle speed of 75 rpm.

0087An eighth principal embodiment of the present invention provides a modified release formulation of gamma-hydroxybutyrate comprising immediate release and modified release portions, wherein: (a) said immediate release portion releases greater than 80% or 90% of its gamma-hydroxybutyrate at one hour, two hours, or three hours when tested in a dissolution apparatus 2 according to USP 38 <711> in 900 mL of 0.1N hydrochloric acid at a temperature of 37°C and a paddle speed of 75 rpm; (b) said modified release portion releases less than 20% or 10% of its gamma-hydroxybutyrate at one hour when tested in a dissolution apparatus 2 according to USP 38 <711> in 900 mL of 0.1N hydrochloric acid at a temperature of 37°C and a paddle speed of 75 rpm; (c) said modified release portion releases greater than 80% or 90% of its gamma-hydroxybutyrate at three hours, two hours, or one hour, when tested in a dissolution apparatus 2 according to USP 38 <711> in 900 mL of 0.05M monobasic potassium phosphate buffer pH 6.8 at a temperature of 37° C and a paddle speed of 75 rpm; and (d) said modified release portion releases greater than 80% or 90% of its gamma-hydroxybutyrate at 3 hours in a dissolution test started in 750 mL of 0.1N hydrochloric acid for 2 hours then switched to 950 mL 0.05M monobasic potassium phosphate buffer adjusted to pH 6.8 at a temperature of 37°C and a paddle speed of 75 rpm.

0088A ninth principal embodiment of the present invention provides a modified release formulation of gamma-hydroxybutyrate, preferably comprising immediate release and modified release portions, wherein a 4.5g, 6g, 7.5g, and 9g dose of the formulation has been shown to achieve a relative bioavailability (RBA) of greater than 80%, 85% or 90% when compared to an equal dose of an immediate release liquid solution of sodium oxybate administered at t₀ and t_4h in equally divided doses, when administered approximately two hours after a standardized evening meal. The relative bioavailability is even higher with larger doses, and with a 6.0 g or 7.5 g or 9.0 g dose is preferably greater than 90, 95 or 100% when compared to an equal dose of an immediate release liquid solution of sodium oxybate administered at t₀ and t_4h in equally divided doses, when administered approximately two hours after a standardized evening meal.

0089A tenth principal embodiment of the present invention provides a modified release formulation of gamma-hydroxybutyrate, wherein a 4.5g and a 9g dose of the formulation has been shown to achieve a relative bioavailability (RBA) of greater than 80% when compared to an equal dose of an immediate release liquid solution of sodium oxybate administered at t₀ and t_4h in equally divided doses, when administered approximately two hours after a standardized evening meal.

0090An eleventh principal embodiment of the present invention provides a modified release formulation of gamma-hydroxybutyrate, preferably comprising immediate release and modified release portions, that yields a plasma concentration versus time curve when administered once nightly at a strength of 4.5 g, 6.0 g, or 7.5 g approximately two hours after a standardized evening meal substantially as depicted in <figref idref="f0006">Figure 12</figref> or <figref idref="f0007">Figure 13</figref> for the corresponding strength.

0091A twelfth principal embodiment of the present invention provides a modified release formulation of gamma-hydroxybutyrate, preferably comprising immediate release and modified release portions, that yields a plasma concentration versus time curve when administered once nightly at a strength of 4.5g approximately two hours after a standardized evening meal substantially as depicted in <figref idref="f0011">Figure 22</figref>.

0092A thirteenth principal embodiment of the present invention provides a modified release formulation of gamma-hydroxybutyrate, preferably comprising immediate release and modified release portions, that yields a dissolution profile substantially as depicted in <figref idref="f0004">Figure 7 and Figure 8</figref>.

0093A fourteenth principal embodiment of the present invention provides a modified release formulation of gamma-hydroxybutyrate, preferably comprising immediate release and modified release portions, that yields a dissolution profile substantially as depicted in <figref idref="f0010">Figure 20</figref> and <figref idref="f0011">Figure 21</figref>.

0094A fifteenth principal embodiment of the present invention provides a modified release formulation of gamma-hydroxybutyrate, preferably comprising immediate release and modified release portions that yields a dissolution profile substantially as depicted in <figref idref="f0002">Figure 3</figref> or <figref idref="f0008">16</figref>.

0095In a sixteenth principal embodiment, the invention provides a modified release formulation of gamma-hydroxybutyrate, comprising immediate release and modified release portions that yields a dissolution profile between the minimum and maximum values depicted in <figref idref="f0013">Figure 25 and Figure 26</figref>.

0096In a seventeenth principal embodiment, the invention provides a modified release formulation of gamma-hydroxybutyrate, comprising immediate release and modified release portions that yields a dissolution profile between the minimum and maximum values depicted in <figref idref="f0014">Figure 27 and Figure 28</figref>.

0097In an eighteenth principal embodiment the invention provides a modified release formulation of gamma-hydroxybutyrate yielding a dissolution profile substantially as shown in any one of <figref idref="f0015 f0016 f0017 f0018 f0019 f0020 f0021 f0022 f0023 f0024 f0025 f0026 f0027 f0028 f0029 f0030 f0031 f0032 f0033 f0034 f0035 f0036 f0037 f0038 f0039 f0040 f0041 f0042 f0043 f0044 f0045">Figures 29 through 89</figref>. It will be understood that this seventeenth principal embodiment can be limited only to one of these dissolution profiles.

0098A nineteenth principal embodiment of the present invention provides a modified release formulation of gamma-hydroxybutyrate, preferably comprising immediate release and modified release portions, that yields a plasma concentration versus time curve when administered once nightly at a strength of 4.5 g, 7.5 g or 9.0 g approximately two hours after a standardized evening meal substantially as depicted in <figref idref="f0046">Figure 90</figref> for the corresponding strength.

0099In any of these principal embodiments, the formulation is preferably effective to treat narcolepsy Type 1 or Type 2. The formulation is also preferably effective to induce sleep for six to eight, most preferably eight consecutive hours.

0100In any of these principal embodiments, the formulation preferably comprises immediate release and modified release portions, wherein the modified release portion comprises gamma hydroxybutyrate particles coated by a polymer carrying free carboxylic groups and a hydrophobic compound having a melting point equal or greater than 40°C, and the ratio of gamma-hydroxybutyrate in the immediate release portion and the modified release portion is from 10/90 to 65/35. The polymers comprising free carboxylic groups preferably have a pH dissolution trigger of from 5.5 to 6.97 and are preferably methacrylic acid copolymers having a pH dissolution trigger of from 5.5 to 6.97.

Principal Structural Embodiments

0101In a first principal structural embodiment, the invention provides a modified release formulation of gamma-hydroxybutyrate comprising immediate release and modified release portions, wherein: (a) the modified release portion comprises coated particles of gamma-hydroxybutyrate; (b) the coating comprises a polymer carrying free carboxylic groups and a hydrophobic compound having a melting point equal or greater than 40°C; and (c) the ratio of gamma-hydroxybutyrate in the immediate release portion and the modified release portion is from 10/90 to 65/35.

0102In a second principal structural embodiment the invention provides a modified release formulation of gamma-hydroxybutyrate comprising immediate release and modified release portions, a suspending or viscosifying agent, and an acidifying agent, wherein: (a) the modified release portion comprises coated particles of gamma-hydroxybutyrate; (b) the coating comprises a polymer carrying free carboxylic groups and a hydrophobic compound having a melting point equal or greater than 40°C; and (c) the ratio of gamma-hydroxybutyrate in the immediate release portion and the modified release portion is from 10/90 to 65/35.

0103In a third principal structural embodiment the invention provides a modified release formulation of gamma-hydroxybutyrate comprising immediate release and modified release portions, wherein: (a) the modified release portion comprises coated particles of gamma-hydroxybutyrate; (b) the coating comprises a polymer carrying free carboxylic groups and a hydrophobic compound having a melting point equal or greater than 40°C; (c) the weight ratio of the hydrophobic compound to the polymer carrying free carboxylic groups is from 0.4 to 4; (d) the ratio of gamma-hydroxybutyrate in the immediate release portion and the modified release portion is from 10/90 to 65/35; and (e) the coating is from 10 to 50% of the weight of the particles.

0104In a fourth principal structural embodiment the invention provides a modified release formulation of gamma-hydroxybutyrate comprising immediate release and modified release portions, wherein: (a) the modified release portion comprises coated particles of gamma-hydroxybutyrate; (b) the coating comprises a polymer carrying free carboxylic groups having a pH trigger of from 5.5 to 6.97 and a hydrophobic compound having a melting point equal or greater than 40°C; (c) the weight ratio of the hydrophobic compound to the polymer carrying free carboxylic groups is from 0.4 to 4; (d) the ratio of gamma-hydroxybutyrate in the immediate release portion and the modified release portion is from 10/90 to 65/35; and (e) the coating is from 10 to 50% of the weight of the particles.

0105In a fifth principal structural embodiment the invention provides a modified release formulation of gamma-hydroxybutyrate comprising immediate release and modified release portions, wherein: (a) the modified release portion comprises coated particles of gamma-hydroxybutyrate; (b) the coating comprises a methacrylic acid copolymer carrying free carboxylic groups having a pH trigger of from 5.5 to 6.97 and a hydrophobic compound having a melting point equal or greater than 40°C; (c) the weight ratio of the hydrophobic compound to the polymer carrying free carboxylic groups is from 0.4 to 4; (d) the ratio of gamma-hydroxybutyrate in the immediate release portion and the modified release portion is from 10/90 to 65/35; and (e) the coating is from 10 to 50% of the weight of the particles.

Discussion of Pharmacokinetic and Dissolution Sub-embodiments

0106As mentioned in the definitions section of this document, each of the sub-embodiments can be used to further characterize and limit each of the foregoing principal embodiments. In addition, more than one of the following sub-embodiments can be combined and used to further characterize and limit each of the foregoing principal embodiments, in any manner that is mathematically and physically possible.

0107In various sub-embodiments of the foregoing principal embodiments a 7.5 g dose of the modified release formulation of gamma-hydroxybutyrate can be characterized as having been shown to achieve a mean AUC_inf of greater than 245, 265, 285, 300, 315, 325, 340, 350, 375, 400, 425, or 450 hrxmicrogram/mL when administered once approximately two hours after a standardized evening meal. An upper limit on mean AUC_inf for such 7.5 g dose can be set at 500 or 550 hrmicrogram/mL.

0108In additional sub-embodiments of the foregoing principal embodiments a 7.5 g dose of the modified release formulation of gamma-hydroxybutyrate can be characterized as having been shown to achieve a mean C_max of greater than 65, 70, 75, 80, 85, or 90 microgram/mL when administered once approximately two hours after a standardized evening meal. An upper limit on mean C_max for such 7.5 g dose can be set at 125 or 100 microgram/mL.

0109In additional sub-embodiments of the forgoing principal embodiments a 7.5g dose of the modified release formulation of gamma-hydroxybutyrate can be characterized as having been shown to achieve a mean C_8h that is from 50% to 130%, from 60% to 130%, from 70 to 130%, from 75% to 125%, from 80% to 125%, from 80 to 120%, or from 90% to 110% of the mean C_8h provided by an equal dose of immediate release liquid solution of gamma-hydroxybutyrate administered at t₀ and t_4h in two equally divided doses, when administered approximately two hours after a standardized evening meal.

0110In one sub-embodiment, a 7.5 g dose of the formulation has been shown to achieve a mean AUC_inf of greater than 340 hr●microgram/mL, and a mean C_8h that is from 50% to 130% of the mean C_8h provided by an equal dose of immediate release liquid solution of sodium oxybate administered at t₀ and t_4h in equally divided doses approximately two hours after a standardized evening meal.

0111Further sub-embodiments can be characterized based on the dissolution properties of the entire (or finished) modified release formulation of gamma-hydroxybutyrate in 0.1N hydrochloric acid dissolution medium. Thus, in additional sub-embodiments the entire modified release formulation of gamma-hydroxybutyrate releases greater than 30%, 35%, 40%, or 45%, and less than 70%, 65%, 60%, or 55%, of its gamma-hydroxybutyrate at one hour when tested in a dissolution apparatus 2 according to USP 38 <711> in 900 mL of 0.1N hydrochloric acid at a temperature of 37°C and a paddle speed of 75 rpm.

0112Further sub-embodiments can be defined based on the dissolution properties of the modified release portion of the formulation of gamma-hydroxybutyrate in a phosphate buffer pH 6.8 dissolution medium. Thus, in additional sub-embodiments the modified release portion releases greater than 80%, 85%, 90%, 95%, 98% or even 99% of its gamma-hydroxybutyrate at 3, 2, 1, 0.5 or 0.25 hours when tested in a dissolution apparatus 2 according to USP 38 <711> in 900 mL of 0.05M monobasic potassium phosphate buffer pH 6.8 at a temperature of 37° C and a paddle speed of 75 rpm. In particular, the modified release portion releases greater than 80% of its gamma-hydroxybutyrate at one hour when tested in a dissolution apparatus 2 according to USP 38 <711> in 900 mL of 0.05M monobasic potassium phosphate buffer pH 6.8 at a temperature of 37° C and a paddle speed of 75 rpm.

0113Still further embodiments can be defined based on the dissolution properties of the modified release portion of the modified release formulation of gamma-hydroxybutyrate in a 0.1N HCl dissolution medium. Thus, in additional sub-embodiments the modified release portion releases less than 20%, 15%, 10%, 5%, or even 2% of its gamma-hydroxybutyrate at one hour when tested in a dissolution apparatus 2 according to USP 38 <711> in 900 mL of 0.1N hydrochloric acid at a temperature of 37°C and a paddle speed of 75 rpm.

0114In additional embodiments, the modified release portion releases less than 20%, 15%, 10%, 5%, or even 2% of its gamma-hydroxybutyrate at one hour and at three hours and more than 30%, 35%, 40%, 45% of its gamma-hydroxybutyrate at ten hours when tested in a dissolution apparatus 2 according to USP 38 <711> in 900 mL of 0.1N hydrochloric acid at a temperature of 37°C and a paddle speed of 75 rpm.

0115Further embodiments can be defined based on the dissolution properties of the immediate release portion of the modified release formulation of gamma-hydroxybutyrate in a 0.1N HCl dissolution medium. Thus, in additional sub-embodiments the immediate release portion releases greater than 80%, 85%, 90%, 95%, 98% or even 99% of its gamma-hydroxybutyrate at one hour when tested in a dissolution apparatus 2 according to USP 38 <711> in 900 mL of 0.1N hydrochloric acid at a temperature of 37°C and a paddle speed of 75 rpm.

0116In another sub-embodiment, the formulation releases (a) at least 80% of its gamma-hydroxybutyrate at three hours when tested in a dissolution apparatus 2 according to USP 38 <711> in 900 mL of 0.05M monobasic potassium phosphate buffer pH 6.8 at a temperature of 37° C and a paddle speed of 75 rpm, and (b) from 10% to 65%, of its gamma-hydroxybutyrate at one hour and three hours when tested in a dissolution apparatus 2 according to USP 38 <711> in 900 mL of 0.1N hydrochloric acid at a temperature of 37°C and a paddle speed of 75 rpm.

0117In another subembodiment, the formulation comprises immediate release and modified release portions, and (a) the formulation releases at least 80% of its gamma-hydroxybutyrate at 3 hours when tested in a dissolution apparatus 2 according to USP 38 <711> in 900 mL of 0.05M monobasic potassium phosphate buffer pH 6.8 at a temperature of 37° C and a paddle speed of 75 rpm, (b) the formulation releases from 10% to 65%, of its gamma-hydroxybutyrate at one hour when tested in a dissolution apparatus 2 according to USP 38 <711> in 900 mL of 0.1N hydrochloric acid at a temperature of 37°C and a paddle speed of 75 rpm, and (c) the modified release portion releases greater than 80% of its gamma-hydroxybutyrate at 3 hours in a dissolution test started in 750 mL of 0.1N hydrochloric acid for 2 hours then switched to 950 mL 0.05M monobasic potassium phosphate buffer adjusted to pH 6.8 at a temperature of 37°C and a paddle speed of 75 rpm.

0118In another sub-embodiment, the formulation comprises immediate release and modified release portions, and (a) the formulation releases at least 80% of its gamma-hydroxybutyrate at 3 hours when tested in a dissolution apparatus 2 according to USP 38 <711> in 900 mL of 0.05M monobasic potassium phosphate buffer pH 6.8 at a temperature of 37° C and a paddle speed of 75 rpm, (b) the formulation releases 10% to 65% of its gamma-hydroxybutyrate at one hour and at three hours when tested in a dissolution apparatus 2 according to USP 38 <711> in 900 mL of 0.1N hydrochloric acid at a temperature of 37°C and a paddle speed of 75 rpm, (c) the formulation releases greater than 60% of its gamma-hydroxybutyrate at 10 hours when tested in a dissolution apparatus 2 according to USP 38 <711> in 900 mL of 0.1N hydrochloric acid at a temperature of 37°C and a paddle speed of 75 rpm, and (d) the modified release portion releases greater than 80% of its gamma-hydroxybutyrate at 3 hours in a dissolution test started in 750 mL of 0.1N hydrochloric acid for 2 hours then switched to 950 mL 0.05M monobasic potassium phosphate buffer adjusted to pH 6.8 at a temperature of 37°C and a paddle speed of 75 rpm.

0119Still further sub-embodiments can be defined based on a pharmacokinetic comparison of the modified release formulation of gamma-hydroxybutyrate to an immediate release solution of gamma-hydroxybutyrate. Therefore, in additional sub-embodiments the modified release formulation of gamma-hydroxybutyrate, preferably in a 4.5g, 6.0g, 7.5g, and 9.0g dose, has been shown to achieve a relative bioavailability (RBA) of greater than 80%, 85%, 90%, or 95% when compared to an equal dose of an immediate release liquid solution of sodium oxybate administered at t₀ and t_4h in equally divided doses, when administered approximately two hours after a standardized evening meal.

0120In additional sub-embodiments of the forgoing principal embodiments the invention provides a modified release formulation of gamma-hydroxybutyrate, preferably comprising immediate release and modified release portions, wherein a 4.5g and 9g dose of the formulation has been shown to achieve a relative bioavailability (RBA) of greater than 80%, 85% or 90% when compared to an equal dose of an immediate release liquid solution of sodium oxybate administered at t₀ and t_4h in equally divided doses, when administered approximately two hours after a standardized evening meal

0121In additional sub-embodiments, a 6.0g or 7.5g or 9.0g dose of the modified release formulation of gamma-hydroxybutyrate has been shown to achieve a relative bioavailability (RBA) of greater than 80%, 85%, 90%, 95% or 100% when compared to an equal dose of an immediate release liquid solution of sodium oxybate administered at t₀ and t_4h in equally divided doses, when administered approximately two hours after a standardized evening meal.

0122The modified release formulations of gamma-hydroxybutyrate of the present invention can also be defined by comparing the area under the concentration/time curve for eight hours to the area under the concentration/time curve calculated to infinity. Thus, in still further sub-embodiments a 4.5 g, 6.0 g, 7.5 g or 9.0 g dose of the modified release formulation of gamma-hydroxybutyrate of the present invention has been shown to achieve a ratio of mean AUC_8h to mean AUC_inf of greater than 0.80, 0.85, 0.90, 0.95 or 0.98 when administered once approximately two hours after a standardized evening meal.

0123In still further sub-embodiments, the modified release formulations of gamma-hydroxybutyrate are defined based on the concentration of gamma-hydroxybutyrate in the blood stream 8 hours after administration. Therefore, in other sub-embodiments the formulation can be characterized by a 4.5g dose of the modified release formulation of gamma-hydroxybutyrate that has been shown to achieve a mean C_8h of from 4.7 to 9.0, from 5.4 to 8.3, from 6.1 to 7.6, from 3.5 to 7.0, or from 4.0 to 5.5 microgram/mL, a 6.0g dose of the modified release formulation of gamma-hydroxybutyrate has been shown to achieve a mean C_8h of from 6.3 to 16.7, from 7.3 to 15.4, from 8.2 to 14.1, from 8.9 to 16.7, from 10.2 to 15.4, or from 11.5 to 14.1 microgram/mL; or a 7.5g dose of the modified release formulation of gamma-hydroxybutyrate has been shown to achieve a mean C_8h of from 13.0 to 40.3, from 16.0 to 26.0, 15.0 to 25.0, from 17.5 to 22.0, from 21.6 to 40.3, from 24.7 to 37.2, or from 27.8 to 34.1 microgram/mL, when administered once approximately two hours after a standardized evening meal, or any combination thereof.

0124The modified release formulations of gamma-hydroxybutyrate of the present invention can also be defined by the concentration/time and dissolution curves that they produce when tested according to the examples of the present invention. Therefore, in other sub-embodiments, a 4.5 g, 6.0 g, or 7.5 g dose of the modified release formulation of gamma-hydroxybutyrate of the present invention has been shown to achieve a time/concentration curve substantially as shown in Figure 13 (a), (b) and (c) respectively herein. In another principal embodiment or sub-embodiment, the formulation has been shown to achieve a dissolution curve substantially as shown in <figref idref="f0004">Figure 7 and 8</figref> or <figref idref="f0010">Figure 20</figref> and <figref idref="f0011">21</figref> herein.

0125The modified release formulations of gamma-hydroxybutyrate of the present invention can also be defined based on the time required to reach maximum blood concentration of gamma-hydroxybutyrate. Thus, in additional sub-embodiments, the modified release formulation of gamma-hydroxybutyrate has been shown to achieve a median T_max of 1.25 to 3.25 hours, preferably of about 1.25, 1.5, 1.75, 2, 2.25, 2.5, 2.75, 3, or 3.25 hours when administered once approximately two hours after a standardized evening meal. A lower limit on the median T_max in any of the foregoing ranges can alternatively be set at 0.5 or 1.0 hours.

0126Additional embodiments can be defined by comparing a dose of the modified release formulation of gamma-hydroxybutyrate, administered once nightly, to the same dose of an immediate release liquid solution of sodium oxybate divided in half and administered twice nightly, 4 hours apart. Thus, in another sub-embodiment a 4.5 g, 6.0 g, 7.5 g or 9.0 g dose of the modified release formulation of gamma-hydroxybutyrate has been shown to achieve a median T_max within one hundred fifty, one hundred twenty, ninety, sixty or thirty minutes of the median T_max of half the dose of an immediate release liquid solution of sodium oxybate, when administered approximately two hours after a standardized evening meal.

0127In still another sub-embodiment a 4.5 g, 6.0 g, 7.5 g or 9.0 g dose of the modified release formulation of gamma-hydroxybutyrate has been shown to achieve a mean C_6h or mean C_7h greater than, and a mean C_10h less than, the mean C_4h of half the dose of an immediate release liquid solution of sodium oxybate, when administered approximately two hours after a standardized evening meal.

0128Additional embodiments can be defined by comparing the pharmacokinetic profile of a dose of the modified release formulation of gamma-hydroxybutyrate administered once nightly to the same dose of an immediate release liquid solution of sodium oxybate divided in half and administered twice nightly, 4 hours apart. Thus, in another sub-embodiment a modified release formulation of gamma-hydroxybutyrate according to the invention has been shown to achieve a ratio of its mean C_3h to the mean C_max of the first half dose of the immediate release liquid solution of sodium oxybate from 0.6 to 1.2, preferably from 0.7 to 1.1 and most preferably from 0.8 to 1. In another sub-embodiment, a modified release formulation of gamma-hydroxybutyrate according to the invention has been shown to achieve a ratio of its mean C_4h to the mean C_max of the first half dose of the immediate release liquid solution of sodium oxybate from 0.5 to 1.1, preferably from 0.6 to 1 and most preferably from 0.7 to 0.9. In another sub-embodiment, a modified release formulation of gamma-hydroxybutyrate according to the invention has been shown to achieve a ratio of its mean C_4.5h to the mean C_max of the first half dose of the immediate release liquid solution of gamma-hydroxybutyrate from 0.5 to 1, preferably from 0.5 to 0.9 and most preferably from 0.6 to 0.8.

0129Additional sub-embodiments can be defined by the range of mean blood concentrations of gamma-hydroxybutyrate achieved 3, 4, 4.5 or 5 hours after administration once nightly by a modified release formulation of gamma-hydroxybutyrate according to the invention at the dose of 7.5g. Thus, in another sub-embodiment, a 7.5g dose ofthe modified release formulation of gamma-hydroxybutyrate has been shown to achieve a mean C_3h of 43 to 81 microgram/mL, preferably 49 to 75 microgram/mL and more preferably 55 to 69 microgram/mL. In another sub-embodiment, a 7.5g dose of the modified release formulation of gamma-hydroxybutyrate has been shown to achieve a mean C_4h of 40 to 75 microgram/mL, preferably 45 to 69 microgram/mL and more preferably 51 to 64 microgram/mL. In another sub-embodiment, a 7.5g dose of the modified release formulation of gamma-hydroxybutyrate has been shown to achieve a mean C_4.5h of 35 to 67 microgram/mL, preferably 40 to 62 microgram/mL and more preferably 45 to 56 microgram/mL. In another sub-embodiment, a 7.5g dose of the modified release formulation of gamma-hydroxybutyrate has been shown to achieve a mean C_5h of 31 to 59 microgram/mL, preferably 36 to 55 microgram/mL and more preferably 40 to 50 microgram/mL.

0130In another subembodiment, a 7.5 g dose of the formulation has been shown to achieve a mean AUC_inf of greater than 300 hr●microgram/mL and a mean C_max of greater than 70 microgram/mL when administered once approximately two hours after a standardized evening meal.

0131In still another subembodiment, a 7.5 g dose of the formulation has been shown to achieve a mean AUC_inf of greater than 350 hr●microgram/mL and a mean C_max of greater than 80 microgram/mL when administered once approximately two hours after a standardized evening meal.

0132In another subembodiment, a 4.5, 6.0, 7.5 and 9.0 g dose of the formulation has been shown to achieve a mean AUC_inf of greater than 80% of the mean AUC_inf provided by an equal dose of immediate release liquid solution of sodium oxybate administered at t₀ and t_4h in equally divided doses approximately two hours after a standardized evening meal, and a mean C_8h less than 95%, 90 or 85% of the mean C_8h provided by an equal dose of immediate release liquid solution of sodium oxybate administered at t₀ and t_4h in equally divided doses approximately two hours after a standardized evening meal.

0133Additional embodiments can be defined by comparing the pharmacokinetic profile of a dose of the modified release formulation of gamma-hydroxybutyrate administered once nightly to another dose of an immediate release liquid solution of sodium oxybate divided in half and administered twice nightly, 4 hours apart. Thus, in another sub-embodiment a 7.5g dose of the modified release formulation of gamma-hydroxybutyrate has been shown to achieve a similar pharmacokinetic profile to the pharmacokinetic profile provided by a 2 x 4.5 g dose of sodium oxybate as an immediate release liquid solution administered for the first 4.5g two hours after a standardized evening meal and for the second 4.5g dose, 4 hours after the first dose. Thus, in another sub-embodiment a modified release formulation of gamma-hydroxybutyrate according to the invention administered at the dose of 7.5g has been shown to achieve a ratio of its mean C_3h to the mean C_max of the first 4.5g dose of the immediate release liquid solution of sodium oxybate from 0.5 to 1.1, preferably from 0.6 to 1 and most preferably from 0.7 to 0.9. In another sub-embodiment, a modified release formulation of gamma-hydroxybutyrate according to the invention has been shown to achieve a ratio of its mean C_4h to the mean C_max of the first 4.5g dose of the immediate release liquid solution of sodium oxybate from 0.5 to 1, preferably from 0.6 to 0.9 and most preferably from 0.7 to 0.8. In another sub-embodiment, a modified release formulation of gamma-hydroxybutyrate according to the invention has been shown to achieve a ratio of its mean C_4.5h to the mean C_max of the 4.5g dose of the immediate release liquid solution of sodium oxybate from 0.4 to 0.9, preferably from 0.5 to 0.8 and most preferably from 0.6 to 0.7.

0134In another subembodiment, the modified release formulation of gamma-hydroxybutyrate comprises immediate release and modified release portions, wherein: (a) said immediate release portion releases greater than 80% of its gamma-hydroxybutyrate at one hour when tested in a dissolution apparatus 2 according to USP 38 <711> in 900 mL of 0.1N hydrochloric acid at a temperature of 37°C and a paddle speed of 75 rpm; (b) said modified release portion releases less than 20% of its gamma-hydroxybutyrate at one hour when tested in a dissolution apparatus 2 according to USP 38 <711> in 900 mL of 0.1N hydrochloric acid at a temperature of 37°C and a paddle speed of 75 rpm; and (c) said modified release portion releases greater than 80% of its gamma-hydroxybutyrate at one hour when tested in a dissolution apparatus 2 according to USP 38 <711> in 900 mL of 0.05M monobasic potassium phosphate buffer pH 6.8 at a temperature of 37° C and a paddle speed of 75 rpm.

0135In a preferred embodiment, the modified release formulation of gamma-hydroxybutyrate according to the invention achieves an in vitro dissolution profile: <ol id="ol0001" compact="compact"><li>(a) measured in a dissolution apparatus 2 according to USP 38 <711> in 900 mL of 0.1N hydrochloric acid at a temperature of 37°C and a paddle speed of 75 rpm, characterized by the percentage of gamma-hydroxybutyrate dissolved being: <ol id="ol0002" compact="compact"><li>(i) from 40% to 65% at 1 hour,</li><li>(ii) from 40% to 65% at 3 hours,</li><li>(iii) from 47% to 85% at 8 hours,</li><li>(iv) greater or equal to 60% at 10 hours,</li><li>(v) greater or equal to 80% at 16 hours, and</li></ol></li><li>(b) measured in a dissolution apparatus 2 according to USP 38 <711> in 900 mL of 0.05M monobasic potassium phosphate buffer pH 6.8 at a temperature of 37° C and a paddle speed of 75 rpm, characterized by the percentage of gamma-hydroxybutyrate dissolved being: <ol id="ol0003" compact="compact"><li>(i) from 43% to 94% at 0.25 hour,</li><li>(ii) greater or equal to 65% at 0.35 hour, and</li><li>(iii) greater or equal to 88% at 1 hour.</li></ol></li></ol>

0136In a preferred embodiment, the modified release formulation of gamma-hydroxybutyrate according to the invention achieves an in vitro dissolution profile: <ol id="ol0004" compact="compact"><li>(a) measured in a dissolution apparatus 2 according to USP 38 <711> in 900 mL of 0.1N hydrochloric acid at a temperature of 37°C and a paddle speed of 75 rpm, characterized by the percentage of gamma-hydroxybutyrate dissolved being: <ol id="ol0005" compact="compact"><li>(i) from 40% to 65% at 1 hour,</li><li>(ii) from 40% to 65% at 3 hours,</li><li>(iii) greater or equal to 47% at 8 hours,</li><li>(iv) greater or equal to 60% at 10 hours,</li><li>(v) greater or equal to 80% at 16 hours, and</li></ol></li><li>(b) measured in a dissolution apparatus 2 according to USP 38 <711> in 900 mL of 0.05M monobasic potassium phosphate buffer pH 6.8 at a temperature of 37° C and a paddle speed of 75 rpm, characterized by the percentage of gamma-hydroxybutyrate dissolved being: <ol id="ol0006" compact="compact"><li>(i) from 43% to 94% at 0.25 hour,</li><li>(ii) greater or equal to 65% at 0.35 hour, and</li><li>(iii) greater or equal to 88% at 1 hour.</li></ol></li></ol>

0137In another preferred embodiment, the modified release formulation of gamma-hydroxybutyrate according to the invention achieves an in vitro dissolution profile: <ol id="ol0007" compact="compact"><li>(a) measured in a dissolution apparatus 2 according to USP 38 <711> in 900 mL of 0.1N hydrochloric acid at a temperature of 37°C and a paddle speed of 75 rpm, characterized by the percentage of gamma-hydroxybutyrate dissolved being: <ol id="ol0008" compact="compact"><li>(i) from 40% to 65% at 1 hour,</li><li>(ii) from 40% to 65% at 3 hours,</li><li>(iii) from 47% to 85% at 8 hours,</li><li>(iv) greater or equal to 60% at 10 hours,</li><li>(v) greater or equal to 80% at 16 hours, and</li></ol></li><li>(b) measured in a dissolution apparatus 2 according to USP 38 <711> in 900 mL of 0.05M monobasic potassium phosphate buffer pH 6.8 at a temperature of 37° C and a paddle speed of 75 rpm, characterized by the percentage of gamma-hydroxybutyrate dissolved being: <ol id="ol0009" compact="compact"><li>(i) from 45% to 67% at 1 hour, and</li><li>(ii) greater or equal to 65% at 3 hours.</li></ol></li></ol>

0138In another preferred embodiment, the modified release formulation of gamma-hydroxybutyrate according to the invention achieves an in vitro dissolution profile: <ol id="ol0010" compact="compact"><li>(a) measured in a dissolution apparatus 2 according to USP 38 <711> in 900 mL of 0.1N hydrochloric acid at a temperature of 37°C and a paddle speed of 75 rpm, characterized by the percentage of gamma-hydroxybutyrate dissolved being: <ol id="ol0011" compact="compact"><li>(i) from 40% to 65% at 1 hour,</li><li>(ii) from 40% to 65% at 3 hours,</li><li>(iii) greater or equal to 47% at 8 hours,</li><li>(iv) greater or equal to 60% at 10 hours,</li><li>(v) greater or equal to 80% at 16 hours, and</li></ol></li><li>(b) measured in a dissolution apparatus 2 according to USP 38 <711> in 900 mL of 0.05M monobasic potassium phosphate buffer pH 6.8 at a temperature of 37° C and a paddle speed of 75 rpm, characterized by the percentage of gamma-hydroxybutyrate dissolved being: <ol id="ol0012" compact="compact"><li>(i) from 45% to 67% at 1 hour, and</li><li>(ii) greater or equal to 65% at 3 hours.</li></ol></li></ol>

0139In still another subembodiment, the formulation achieves an in vitro dissolution profile: (a) measured in a dissolution apparatus 2 according to USP 38 <711> in 900 mL of 0.1N hydrochloric acid at a temperature of 37°C and a paddle speed of 75 rpm, characterized by the percentage of gamma-hydroxybutyrate dissolved being: (i) from 40% to 65% at 1 hour, (ii) from 40% to 65% at 3 hours, (iii) greater than 45% at 8 hours, and (b) measured in a dissolution apparatus 2 according to USP 38 <711> in 900 mL of 0.05M monobasic potassium phosphate buffer pH 6.8 at a temperature of 37° C and a paddle speed of 75 rpm, characterized by the percentage of gamma-hydroxybutyrate dissolved being: (i) greater than 40% at 0.5 hour, and (ii) greater than 85% at 1 hour.

0140Alternatively, the formulation can be described as achieving an in vitro dissolution profile measured in a dissolution apparatus 2 according to USP 38 <711> in 900 mL of 0.1N hydrochloric acid at a temperature of 37°C and a paddle speed of 75 rpm, characterized by the percentage of gamma-hydroxybutyrate dissolved being: (i) from 40% to 65% at 1 hour, (ii) from 40% to 65% at 3 hours, and (iii) greater than 45% at 8 hours.

0141In another alternative, the formulation can be described as achieving an in vitro dissolution profile measured in a dissolution apparatus 2 according to USP 38 <711> in 900 mL of 0.05M monobasic potassium phosphate buffer pH 6.8 at a temperature of 37° C and a paddle speed of 75 rpm, characterized by the percentage of gamma-hydroxybutyrate dissolved being: (i) greater than 40% at 0.5 hour, and (ii) greater than 85% at 1 hour.

Structural Sub-embodiments

0142The modified release formulations of gamma-hydroxybutyrate of the present invention can be provided in any dosage form that is suitable for oral administration, including tablets, capsules, liquids, orally dissolving tablets, and the like, but they are preferably provided as dry particulate formulations (i.e. granules, powders, coated particles, microparticles, pellets, microspheres, etc.), in a sachet or other suitable discreet packaging units. Preferably, the formulation is in the form of a powder. A preferred particulate formulation will be mixed with tap water shortly before administration, preferably 50 mL.

0143Preferably, the gamma-hydroxybutyrate is in the form of sodium oxybate.

0144In one subembodiment, the formulation comprises immediate release and modified release portions, wherein: (a) the modified release portion comprises coated microparticles of gamma-hydroxybutyrate; and (b) the ratio of gamma-hydroxybutyrate in the immediate release portion and the modified release portion is from 10/90 to 65/35.

0145In one subembodiment, the formulation comprises immediate release and modified release portions, wherein: (a) the modified release portion comprises coated microparticles of gamma-hydroxybutyrate; and (b) the ratio of gamma-hydroxybutyrate in the immediate release portion and the modified release portion is from 40/60 to 60/40.

0146In another subembodiment, the formulation comprises immediate release and modified release portions, wherein: (a) the modified release portion comprises coated microparticles of gamma-hydroxybutyrate; (b) the coating of said modified release particles of gamma-hydroxybutyrate comprises a polymer carrying free carboxylic groups and a hydrophobic compound having a melting point equal or greater than 40°C; and (c) the ratio of gamma-hydroxybutyrate in the immediate release portion and the modified release portion is from 10/90 to 65/35 or 40/60 to 60/40.

0147In another subembodiment, the formulation comprises immediate release and modified release portions, wherein: (a) the modified release portion comprises coated microparticles of gamma-hydroxybutyrate; (b) the coating of said modified release particles of gamma-hydroxybutyrate comprises a polymer carrying free carboxylic groups and a hydrophobic compound having a melting point equal or greater than 40°C; (c) the weight ratio of the hydrophobic compound to the polymer carrying free carboxylic groups is from 0.4 to 4; (d) the ratio of gamma-hydroxybutyrate in the immediate release portion and the modified release portion is from 10/90 to 65/35 or 40/60 to 60/40; and (e) the coating of said modified release particles of gamma-hydroxybutyrate is from 10 to 50% of the weight of the microparticles.

0148In another subembodiment the formulation comprises immediate release and modified release portions, wherein: (a) the modified release portion comprises coated particles of gamma-hydroxybutyrate; (b) the coating of said modified release particles of gamma-hydroxybutyrate comprises a polymer carrying free carboxylic groups having a pH trigger of from 5.5 to 6.97 and a hydrophobic compound having a melting point equal or greater than 40°C; (c) the weight ratio of the hydrophobic compound to the polymer carrying free carboxylic groups is from 0.4 to 4; (d) the ratio of gamma-hydroxybutyrate in the immediate release portion and the modified release portion is from 10/90 to 65/35 or 40/60 to 60/40; and (e) the coating said modified release particles of gamma-hydroxybutyrate is from 10 to 50% of the weight of the particles.

0149In a particularly preferred sub-embodiment of the immediately preceding sub-embodiments, the polymer carrying free carboxylic groups comprises from 100% poly (methacrylic acid, ethyl acrylate) 1:1 and 0% poly (methacrylic acid, methylmethacrylate) 1:2 to 2% poly (methacrylic acid, ethyl acrylate) 1:1 and 98% poly (methacrylic acid, methylmethacrylate) 1:2; and the hydrophobic compound comprises hydrogenated vegetable oil.

0150In a preferred embodiment, the formulation includes excipients to improve the viscosity and the pourability of the mixture of the particulate formulation with tap water. As such, the particulate formulation comprises, besides the immediate release and modified release particles of gamma-hydroxybutyrate, one or more suspending or viscosifying agents or lubricants.

0151Preferred suspending or viscosifying agents are chosen from the group consisting of xanthan gum, medium viscosity sodium carboxymethyl cellulose, mixtures of microcrystalline cellulose and sodium carboxymethyl cellulose, mixtures of microcrystalline cellulose and guar gum, medium viscosity hydroxyethyl cellulose, agar, sodium alginate, mixtures of sodium alginate and calcium alginate, gellan gum, carrageenan gum grade iota, kappa or lambda, and medium viscosity hydroxypropylmethyl cellulose.

0152Medium viscosity sodium carboxymethyl cellulose corresponds to grade of sodium carboxymethyl cellulose whose viscosity, for a 2% solution in water at 25°C, is greater than 200 mPa·s and lower than 3100 mPa·s.

0153Medium viscosity hydroxyethyl cellulose corresponds to a grade of hydroxyethyl cellulose whose viscosity, for a 2% solution in water at 25°C, is greater than 250 mPa·s and lower than 6500 mPa·s. Medium viscosity hydroxypropylmethyl cellulose corresponds to a grade of hydroxypropylmethyl cellulose whose viscosity, for a 2% solution in water at 20°C, is greater than 80 mPa·s. and lower than 3800 mPa·s.

0154Preferred suspending or viscosifying agents are xanthan gum, especially Xantural 75^™from Kelco, hydroxyethylcellulose, especially Natrosol 250M^™ from Ashland, Kappa carrageenan gum, especially Gelcarin PH812^™ from FMC Biopolymer, and lambda carrageenan gum, especially Viscarin PH209^™ from FMC Biopolymer.

0155In a preferred embodiment, the modified release formulation of gamma-hydroxybutyrate comprises from 1 to 15% of viscosifying or suspending agents, preferably from 2 to 10%, more preferably from 2 to 5%, and most preferably from 2 to 3% of the formulation.

0156In a preferred embodiment, the modified release formulation of gamma-hydroxybutyrate is in the form of a powder that is intended to be dispersed in water prior to administration and further comprises from 1 to 15% of a suspending or viscosifying agent selected from a mixture of xanthan gum, carrageenan gum and hydroxyethylcellulose or xanthan gum and carrageenan gum.

0157In a most preferred embodiment, the modified release formulation of gamma-hydroxybutyrate comprises about 1% of lambda carrageenan gum or Viscarin PH209^™, about 1% of medium viscosity grade of hydroxyethyl cellulose or Natrosol 250M^™, and about 0.7% of xanthan gum or Xantural 75^™. For a 4.5 g dose unit, these percentages will typically equate to about 50mg xanthan gum (Xantural 75^™), about 75mg carragenan gum (Viscarin PH209^™), and about 75mg hydroxyethylcellulose (Natrasol 250M^™).

0158Alternative packages of viscosifying or suspending agents, for a 4.5g dose, include about 50mg xanthan gum (Xantural 75^™) and about 100mg carragenan gum (Gelcarin PH812^™), or about 50mg xanthan gum (Xantural 75^™), about 75mg hydroxyethylcellulose (Natrasol 250M^™), and about 75mg carragenan gum (Viscarin PH109^™).

0159In a preferred embodiment, the modified release formulation of gamma-hydroxybutyrate further comprises a lubricant or a glidant, besides the immediate release and modified release particles of gamma-hydroxybutyrate. Preferred lubricants and glidants are chosen from the group consisting of salts of stearic acid, in particular magnesium stearate, calcium stearate or zinc stearate, esters of stearic acid, in particular glyceryl monostearate or glyceryl palmitostearate, stearic acid, glycerol behenate, sodium stearyl fumarate, talc, and colloidal silicon dioxide.

0160The preferred lubricant or glidant is magnesium stearate.

0161The lubricant or glidant can be used in the particulate formulation in an amount of from 0.1 to 5%. The preferred amount is about 0.5%.

0162Most preferably, the modified release formulation of gamma-hydroxybutyrate comprises about 0.5% of magnesium stearate.

0163A preferred modified release formulation of gamma-hydroxybutyrate further comprises an acidifying agent. The acidifying agent helps to ensure that the release profile of the formulation in 0.1N HCl will remain substantially unchanged for at least 15 minutes after mixing, which is approximately the maximum length of time a patient might require before consuming the dose after mixing the formulation with tap water.

0164In one particular subembodiment the formulation is a powder that is intended to be dispersed in water prior to administration, and further comprising an acidifying agent and a suspending or viscosifying agent, preferably in the weight percentages recited herein.

0165The preferred acidifying agents are chosen from the group consisting of malic acid, citric acid, tartaric acid, adipic acid, boric acid, maleic acid, phosphoric acid, ascorbic acid, oleic acid, capric acid, caprylic acid, and benzoic acid. In a preferred embodiment, the acidifying agent is present in the formulation from 1.2 to 15%, preferably from 1.2 to 10%, preferably from 1.2 to 5%. Preferred acidifying agents are tartaric acid and malic acid, with malic acid being most preferred.

0166When tartaric acid is employed, it is preferably employed in an amount of from 1 to 10%, from 2.5 to 7.5%, or about 5%. In a most preferred embodiment, the amount of malic acid in the modified release formulation of gamma-hydroxybutyrate is from 1.2 to 15%, preferably from 1.2 to 10%, preferably from 1.2 to 5%, and most preferably 1.6% or 3.2%.

0167In a most preferred embodiment, the amount of malic acid in the modified release formulation of gamma hydroxybutyrate is about 1.6%.

0168In a preferred embodiment, the modified release formulation of gamma-hydroxybutyrate is in the form of a powder that is intended to be dispersed in water prior to administration and further comprises: <ol id="ol0013" compact="compact"><li>a) a suspending or viscosifying agent selected from xanthan gum, medium viscosity sodium carboxymethyl cellulose, mixtures of microcrystalline cellulose and sodium carboxymethyl cellulose, mixtures of microcrystalline cellulose and guar gum, medium viscosity hydroxyethyl cellulose, agar, sodium alginate, mixtures of sodium alginate and calcium alginate, gellan gum, carrageenan gum grade iota, kappa or lambda, medium viscosity hydroxypropylmethyl cellulose, and mixtures thereof; and</li><li>b) an acidifying agent selected from malic acid, citric acid, tartaric acid, adipic acid, boric acid, maleic acid, phosphoric acid, ascorbic acid, oleic acid, capric acid, caprylic acid, benzoic acid, and mixtures thereof.</li></ol>

0169In a most preferred embodiment, the modified release formulation of gamma-hydroxybutyrate is in the form of a powder that is intended to be dispersed in water prior to administration and further comprises: from 1.2 to 15% of an acidifying agent selected from malic acid and tartaric acid; and from 1 to 15% of a suspending or viscosifying agent selected from a mixture of xanthan gum, carrageenan gum and hydroxyethylcellulose or xanthan gum and carrageenan gum.

0170The modified release formulation of gamma-hydroxybutyrate preferably includes an immediate release portion and a modified release portion of gamma-hydroxybutyrate, and in a particularly preferred embodiment, the formulation is a particulate formulation that includes a plurality of immediate release gamma-hydroxybutyrate particles and a plurality of modified release gamma-hydroxybutyrate particles. The molar ratio of gamma-hydroxybutyrate in the immediate release and modified release portions preferably ranges from 0.11:1 to 1.86:1, from 0.17:1 to 1.5:1, from 0.25:1 to 1.22:1, from 0.33:1 to 1.22:1, from 0.42:1 to 1.22:1, from 0.53:1 to 1.22:1, from 0.66:1 to 1.22:1, from 0.66:1 to 1.5:1, from 0.8:1 to 1.22:1, and preferably is about 1:1. The molar percentage of gamma-hydroxybutyrate in the immediate release portion relative to the total of gamma-hydroxybutyrate in the formulation preferably ranges from 10% to 65%, from 15 to 60%, from 20 to 55%, from 25 to 55%, from 30 to 55%, from 35 to 55%, from 40 to 55%, from 40 to 60%, or from 45 to 55%, preferably from 40% to 60%. In a preferred embodiment, the molar percentage of the gamma-hydroxybutyrate in the immediate release portion relative to the total of gamma-hydroxybutyrate in the formulation is about 50%. The molar percentage of gamma-hydroxybutyrate in the modified release portion relative to the total of gamma-hydroxybutyrate in the formulation preferably ranges from 90% to 35%, from 85 to 40%, from 80 to 45%, from 75 to 45%, from 70 to 45%, from 65 to 45%, from 60 to 45%, from 60 to 40%, or from 55 to 45%, preferably from 60% to 40%. In a preferred embodiment, the molar ratio of the gamma-hydroxybutyrate in the modified release portion relative to the total of gamma-hydroxybutyrate in the formulation is about 50%. The weight percentage of the IR microparticles relative to the total weight of IR microparticles and MR microparticles, preferably ranges from 7.2% to 58.2%, from 11.0% to 52.9%, from 14.9% to 47.8%, from 18.9% to 47.8%, from 23.1% to 47.8%, from 27.4% to 47.8%, from 31.8% to 47.8%, from 31.8% to 52.9%, or from 36.4% to 47.8%. In other embodiments, the weight percentage of the IR microparticles relative to the total weight of IR microparticles and MR microparticles preferably ranges from 5.9% to 63.2%, from 9.1% to 58.1%, from 12.4% to 53.1%, from 19.9% to 53.1%, from 19.6% to 53.1%, from 23.4% to 53.1%, from 27.4% to 53.1% from 27.4% to 58.1%, preferably from 31,7% to 53.1%.

0171In a preferred embodiment, the finished formulation comprises 50% of its sodium oxybate content in immediate-release particles consisting of 80.75% w/w of sodium oxybate, 4.25% w/w of Povidone K30 and 15% of microcrystalline cellulose spheres with a volume mean diameter of about 95 microns to 450 microns and 50% of its sodium oxybate content in modified release particles consisting of 10.5 % w/w of microcrystalline cellulose spheres with a volume mean diameter of about 95 microns to about 450 microns, layered with 56.5% w/w of sodium oxybate mixed with 3% w/w of Povidone^™ K30 and finally coated with a coating composition consisting of 18% w/w of hydrogenated vegetable oil (Lubritab^™ or equivalent), 4% of methacrylic acid copolymer type C (Eudragit^™ L100-55 or equivalent) and 8% of methacrylic acid copolymer type B (Eudragit^™ S100 or equivalent).

0172In a preferred embodiment, the finished formulation comprises 50% of its sodium oxybate content in immediate-release particles consisting of 80.75% w/w of sodium oxybate, 4.25% w/w of Povidone K30 and 15% of microcrystalline cellulose spheres with a volume mean diameter of about 95 microns to 170 microns and 50% of its sodium oxybate content in modified release particles consisting of 10.5 % w/w of microcrystalline cellulose spheres with a volume mean diameter of about 95 microns to about 170 microns, layered with 56.5% w/w of sodium oxybate mixed with 3% w/w of Povidone^™ K30 and finally coated with a coating composition consisting of 18% w/w of hydrogenated vegetable oil (Lubritab^™ or equivalent), 4% of methacrylic acid copolymer type C (Eudragit^™ L100-55 or equivalent) and 8% of methacrylic acid copolymer type B (Eudragit^™ S100 or equivalent).

0173In a preferred embodiment, the finished formulation comprises 50% of its sodium oxybate content in immediate-release particles consisting of 80.75% w/w of sodium oxybate, 4.25% w/w of Povidone K30 and 15% of microcrystalline cellulose spheres with a volume mean diameter of about 95 microns to about 450 microns and 50% of its sodium oxybate content in modified release particles consisting of 11.3% w/w of microcrystalline cellulose spheres with a volume mean diameter of about 95 microns to about 450 microns, layered with 60.5% w/w of sodium oxybate mixed with 3.2% w/w of Povidone^™ K30 and finally coated with a coating composition consisting of 15 % w/w of hydrogenated vegetable oil (Lubritab^™ or equivalent), 0.75% of methacrylic acid copolymer type C (Eudragit^™ L100-55 or equivalent) and 9.25% of methacrylic acid copolymer type B (Eudragit^™ S100 or equivalent).

0174In a preferred embodiment, the finished formulation comprises 50% of its sodium oxybate content in immediate-release particles consisting of 80.75% w/w of sodium oxybate, 4.25% w/w of Povidone^™ K30 and 15% of microcrystalline cellulose spheres with a volume mean diameter of about 95 microns to about 170 microns and 50% of its sodium oxybate content in modified release particles consisting of 11.3% w/w of microcrystalline cellulose spheres with a volume mean diameter of about 95 microns to about 170 microns, layered with 60.5% w/w of sodium oxybate mixed with 3.2% w/w of Povidone^™ K30 and finally coated with a coating composition consisting of 15 % w/w of hydrogenated vegetable oil (Lubritab^™ or equivalent), 0.75% of methacrylic acid copolymer type C (Eudragit^™ L100-55 or equivalent) and 9.25% of methacrylic acid copolymer type B (Eudragit^™ S100 or equivalent).

0175In a preferred embodiment, the finished formulation comprises 50% of its gamma-hydroxybutyrate content in immediate-release particles consisting of 80.75% w/w of potassium salt of gamma-hydroxybutyric acid, 4.25% w/w of Povidone K30 and 15% of microcrystalline cellulose spheres with a volume mean diameter of about 95 microns to about 450 microns and 50% of its gamma-hydroxybutyrate content in modified release particles consisting of 10.5 % w/w of microcrystalline cellulose spheres with a volume mean diameter of about 95 microns to about 450 microns, layered with 56.5% w/w of sodium oxybate mixed with 3% w/w of Povidone^™ K30 and finally coated with a coating composition consisting of 18% w/w of hydrogenated vegetable oil (Lubritab^™ or equivalent), 4% of methacrylic acid copolymer type C (Eudragit^™ L100-55 or equivalent) and 8% of methacrylic acid copolymer type B (Eudragit^™ S100 or equivalent).

0176In a preferred embodiment, the finished formulation comprises 50% of its gamma-hydroxybutyrate content in immediate-release particles consisting of 80.75% w/w of potassium salt of gamma-hydroxybutyric acid, 4.25% w/w of Povidone K30 and 15% of microcrystalline cellulose spheres with a volume mean diameter of about 95 microns to about 170 microns and 50% of its gamma-hydroxybutyrate content in modified release particles consisting of 10.5 % w/w of microcrystalline cellulose spheres with a volume mean diameter of about 95 microns to about 170 microns, layered with 56.5% w/w of sodium oxybate mixed with 3% w/w of Povidone^™ K30 and finally coated with a coating composition consisting of 18% w/w of hydrogenated vegetable oil (Lubritab^™ or equivalent), 4% of methacrylic acid copolymer type C (Eudragit^™ L100-55 or equivalent) and 8% of methacrylic acid copolymer type B (Eudragit^™ S100 or equivalent).

0177In a preferred embodiment, the finished formulation comprises 16.7% ofits gamma-hydroxybutyrate content in immediate-release particles consisting of 80.75% w/w of potassium salt of gamma-hydroxybutyric acid, 4.25% w/w of Povidone K30 and 15% of microcrystalline cellulose spheres with a volume mean diameter of about 95 microns to about 450 microns, 16.7% of its gamma-hydroxybutyrate content in immediate-release particles consisting of 80.75% w/w of magnesium salt of gamma-hydroxybutyric acid, 4.25% w/w of Povidone K30 and 15% of microcrystalline cellulose spheres with a volume mean diameter of about 95 microns to about 450 microns, 16.7% of its gamma-hydroxybutyrate content in immediate-release particles consisting of 80.75% w/w of calcium salt of gamma-hydroxybutyric acid, 4.25% w/w of Povidone K30 and 15% of microcrystalline cellulose spheres with a volume mean diameter of about 95 microns to about 450 microns and 50% of its gamma-hydroxybutyrate content in modified release particles consisting of 10.5 % w/w of microcrystalline cellulose spheres with a volume mean diameter of about 95 microns to about 450 microns, layered with 56.5% w/w of sodium oxybate mixed with 3% w/w of Povidone^™ K30 and finally coated with a coating composition consisting of 18% w/w of hydrogenated vegetable oil (Lubritab^™ or equivalent), 4% of methacrylic acid copolymer type C (Eudragit^™ L100-55 or equivalent) and 8% of methacrylic acid copolymer type B (Eudragit^™ S100 or equivalent).

0178In a preferred embodiment, the finished formulation comprises 16.7% ofits gamma-hydroxybutyrate content in immediate-release particles consisting of 80.75% w/w of potassium salt of gamma-hydroxybutyric acid, 4.25% w/w of Povidone K30 and 15% of microcrystalline cellulose spheres with a volume mean diameter of about 95 microns to about 170 microns, 16.7% of its gamma-hydroxybutyrate content in immediate-release particles consisting of 80.75% w/w of magnesium salt of gamma-hydroxybutyric acid, 4.25% w/w of Povidone K30 and 15% of microcrystalline cellulose spheres with a volume mean diameter of about 95 microns to about 170 microns, 16.7% of its gamma-hydroxybutyrate content in immediate-release particles consisting of 80.75% w/w of calcium salt of gamma-hydroxybutyric acid, 4.25% w/w of Povidone K30 and 15% of microcrystalline cellulose spheres with a volume mean diameter of about 95 microns to about 170 microns and 50% of its gamma-hydroxybutyrate content in modified release particles consisting of 10.5 % w/w of microcrystalline cellulose spheres with a volume mean diameter of about 95 microns to about 170 microns, layered with 56.5% w/w of sodium oxybate mixed with 3% w/w of Povidone^™ K30 and finally coated with a coating composition consisting of 18% w/w of hydrogenated vegetable oil (Lubritab^™ or equivalent), 4% of methacrylic acid copolymer type C (Eudragit^™ L100-55 or equivalent) and 8% of methacrylic acid copolymer type B (Eudragit^™ S100 or equivalent).

0179In a preferred embodiment, the finished formulation comprises 50% of its gamma-hydroxybutyrate content in immediate-release particles consisting of 80.75% w/w of potassium salt of gamma-hydroxybutyric acid, 4.25% w/w of Povidone K30 and 15% of microcrystalline cellulose spheres with a volume mean diameter of about 95 microns to about 450 microns and 50% of its gamma-hydroxybutyrate content in modified release particles consisting of 10.5 % w/w of microcrystalline cellulose spheres with a volume mean diameter of about 95 microns to about 450 microns, layered with 56.5% w/w of calcium salt of gamma-hydroxybutyric acid mixed with 3% w/w of Povidone^™ K30 and finally coated with a coating composition consisting of 18% w/w of hydrogenated vegetable oil (Lubritab^™ or equivalent), 4% of methacrylic acid copolymer type C (Eudragit^™ L100-55 or equivalent) and 8% of methacrylic acid copolymer type B (Eudragit^™ S100 or equivalent).

0180In a preferred embodiment, the finished formulation comprises 50% of its gamma-hydroxybutyrate content in immediate-release particles consisting of 80.75% w/w of potassium salt of gamma-hydroxybutyric acid, 4.25% w/w of Povidone K30 and 15% of microcrystalline cellulose spheres with a volume mean diameter of about 95 microns to about 170 microns and 50% of its gamma-hydroxybutyrate content in modified release particles consisting of 10.5 % w/w of microcrystalline cellulose spheres with a volume mean diameter of about 95 microns to about 170 microns, layered with 56.5% w/w of calcium salt of gamma-hydroxybutyric acid mixed with 3% w/w of Povidone^™ K30 and finally coated with a coating composition consisting of 18% w/w of hydrogenated vegetable oil (Lubritab^™ or equivalent), 4% of methacrylic acid copolymer type C (Eudragit^™ L100-55 or equivalent) and 8% of methacrylic acid copolymer type B (Eudragit^™ S100 or equivalent).

Other Characteristics of Immediate Release Portion

0181The immediate release portion of the formulation can take any form capable of achieving an immediate release of the gamma-hydroxybutyrate when ingested. For example, when the formulation is a particulate formulation, the formulation can include unmodified "raw" gamma-hydroxybutyrate, rapidly dissolving gamma-hydroxybutyrate granules, particles or microparticles comprised of a core covered by a gamma-hydroxybutyrate loaded layer containing a binder such as povidone.

0182The IR granules or particles of gamma-hydroxybutyrate can be made using any manufacturing process suitable to produce the required particles, including: <ul id="ul0002" list-style="bullet" compact="compact"><li>agglomeration of the gamma-hydroxybutyrate sprayed preferably in the molten state, such as the Glatt ProCell^™ technique,</li><li>extrusion and spheronization of the gamma-hydroxybutyrate, optionally with one or more physiologically acceptable excipients,</li><li>wet granulation of the gamma-hydroxybutyrate, optionally with one or more physiologically acceptable excipients,</li><li>compacting of the gamma-hydroxybutyrate, optionally with one or more physiologically acceptable excipients,</li><li>granulation and spheronization of the gamma-hydroxybutyrate, optionally with one or more physiologically acceptable excipients, the spheronization being carried out for example in a fluidized bed apparatus equipped with a rotor, in particular using the Glatt CPS^™ technique,</li><li>spraying of the gamma-hydroxybutyrate, optionally with one or more physiologically acceptable excipients, for example in a fluidized bed type apparatus equipped with zig-zag filter, in particular using the Glatt MicroPx^™ technique, or</li><li>spraying, for example in a fluidized bed apparatus optionally equipped with a partition tube or Wurster tube, the gamma-hydroxybutyrate, optionally with one or more physiologically acceptable excipients, in dispersion or in solution in an aqueous or organic solvent on a core.</li></ul>

0183Preferably, the immediate release portion of the formulation is in the form of microparticles comprising the immediate release gamma-hydroxybutyrate and optional pharmaceutically acceptable excipients. In a preferred embodiment, the immediate release microparticles of gamma-hydroxybutyrate have a volume mean diameter D(4,3) of from 10 to 1000 microns, preferably from 95 to 600 microns, more preferably from 150 to 400 microns. Most preferably their volume mean diameter is about 270 microns.

0184The preferred immediate release particles of gamma-hydroxybutyrate of the present invention comprises a core and a layer deposited on the core that contains the gamma-hydroxybutyrate. The core can be any particle chosen from the group consisting of: <ul id="ul0003" list-style="bullet" compact="compact"><li>crystals or spheres of lactose, sucrose (such as Compressuc^™ PS from Tereos), microcrystalline cellulose (such as Avicel^™ from FMC Biopolymer, Cellet^™ from Pharmatrans or Celphere^™ from Asahi Kasei), sodium chloride, calcium carbonate (such as Omyapure^™ 35 from Omya), sodium hydrogen carbonate, dicalcium phosphate (such as Dicafos^™ AC 92-12 from Budenheim) or tricalcium phosphate (such as Tricafos^™ SC93-15 from Budenheim);</li><li>composite spheres or granules, for example sugar spheres comprising sucrose and starch (such as Suglets^™ from NP Pharm), spheres of calcium carbonate and starch (such as Destab^™ 90 S Ultra 250 from Particle Dynamics) or spheres of calcium carbonate and maltodextrin (such as Huberca^™ CCG4100 from Huber).</li></ul>

0185The core can also comprise other particles of pharmaceutically acceptable excipients such as particles of hydroxypropyl cellulose (such as Klucel^™ from Aqualon Hercules), guar gum particles (such as Grinsted^™ Guar from Danisco), xanthan particles (such as Xantural^™ 180 from CP Kelco).

0186According to a particular embodiment of the invention, the cores are sugar spheres or microcrystalline cellulose spheres, such as Cellets^™ 90, Cellets^™ 100 or Cellets^™ 127 marketed by Pharmatrans, or also Celphere^™ CP 203, Celphere^™ CP305, Celphere^™ SCP 100. Preferably the core is a microcrystalline cellulose sphere. Most preferably the core is a Cellets^™ 127 from Pharmatrans.

0187The core preferably has a mean volume diameter of about 95 to about 450 microns, preferably about 95 to about 170 microns, most preferably about 140 microns.

0188The layer deposited onto the core comprises the immediate release gamma-hydroxybutyrate. Preferably the layer also comprises a binder, which can be chosen from the group consisting of: <ul id="ul0004" list-style="bullet" compact="compact"><li>low molecular weight hydroxypropyl cellulose (such as Klucel^™ EF from Aqualon- Hercules), low molecular weight hydroxypropyl methylcellulose (or hypromellose) (such as Methocel^™ E3 or E5 from Dow), or low molecular weight methylcellulose (such as Methocel^™ A15 from Dow);</li><li>low molecular weight polyvinyl pyrrolidone (or povidone) (such as Plasdone^™ K29/32 from ISP or Kollidon^™ 30 from BASF), vinyl pyrrolidone and vinyl acetate copolymer (or copovidone) (such as Plasdone^™: S630 from ISP or Kollidon^™ VA 64 from BASF);</li><li>dextrose, pregelatinized starch, maltodextrin; and mixtures thereof.</li></ul>

0189Low molecular weight hydroxypropyl cellulose corresponds to grades of hydroxypropyl cellulose having a molecular weight of less than 800,000 g/mol, preferably less than or equal to 400,000 g/mol, and in particular less than or equal to 100,000 g/mol. Low molecular weight hydroxypropyl methylcellulose (or hypromellose) corresponds to grades of hydroxypropyl methylcellulose the solution viscosity of which, for a 2% solution in water and at 20° C, is less than or equal to 1,000 mPa·s, preferably less than or equal to 100 mPa·s and in particular less than or equal to 15 mPa·s. Low molecular weight polyvinyl pyrrolidone (or povidone) corresponds to grades of polyvinyl pyrrolidone having a molecular weight of less than or equal to 1,000,000 g/mol, preferably less than or equal to 800,000 g/mol, and in particular less than or equal to 100,000 g/mol.

0190Preferably, the binding agent is chosen from low molecular weight polyvinylpyrrolidone or povidone (for example, Plasdone^™ K29/32 from ISP), low molecular weight hydroxypropyl cellulose (for example, Klucel^™ EF from Aqualon-Hercules), low molecular weight hydroxypropyl methylcellulose or hypromellose (for example, Methocel^™ E3 or E5 from Dow) and mixtures thereof.

0191The preferred binder is povidone K30 or K29/32, especially Plasdone^™ K29/32 from ISP. The binder can be present in an amount of 0 to 80%, 0 to 70%, 0 to 60%, 0 to 50%, 0 to 40%, 0 to

019230%, 0 to 25%, 0 to 20%, 0 to 15%, 0 to 10%, or from 1 to 9%, most preferably 5% of binder based on the total weight of the immediate release coating.

0193The preferred amount of binder is 5% of binder over the total mass of gamma-hydroxybutyrate and binder.

0194The layer deposited on the core can represent at least 10% by weight, and even greater than 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85 or 90% by weight of the total weight of the immediate release particle of gamma-hydroxybutyrate. Most preferably, the layer deposited on the core represents about 85% of the weight of the immediate release particle of gamma-hydroxybutyrate.

0195According to a preferred embodiment, the immediate-release particles comprise 80.75% w/w of gamma-hydroxybutyrate, 4.25% w/w of Povidone K30 and 15% of microcrystalline cellulose spheres.

0196According to a preferred embodiment, the immediate-release particles comprise 80.75% w/w of gamma-hydroxybutyrate, 4.25% w/w of Povidone K30 and 15% of microcrystalline cellulose spheres with a volume mean diameter of about 95 microns to about 450 microns.

0197According to a preferred embodiment, the immediate-release particles comprise 80.75% w/w of gamma-hydroxybutyrate, 4.25% w/w of Povidone K30 and 15% of microcrystalline cellulose spheres with a volume mean diameter of about 95 microns to about 170 microns.

0198According to a preferred embodiment, the immediate-release particles comprise 80.75% w/w of sodium oxybate, 4.25% w/w of Povidone K30 and 15% of microcrystalline cellulose spheres.

0199According to another preferred embodiment, the immediate-release particles comprise 80,75% w/w of potassium salt of gamma-hydroxybutyric acid, 4.25% w/w of Povidone K30 and 15% of microcrystalline cellulose spheres.

0200According to another preferred embodiment, the immediate-release particles comprise 80,75% w/w of calcium salt of gamma-hydroxybutyric acid, 4.25% w/w of Povidone K30 and 15% of microcrystalline cellulose spheres.

0201According to another preferred embodiment, the immediate-release particles comprise 80,75% w/w of magnesium salt of gamma-hydroxybutyric acid, 4.25% w/w of Povidone K30 and 15% of microcrystalline cellulose spheres.

0202According to another embodiment, the immediate-release particles are manufactured by dissolving the gamma-hydroxybutyrate and the Povidone K30 in a mixture of water/ethanol 40/60 w/w and spraying the resulting solution onto the surface of the microcrystalline cellulose spheres.

Other Characteristics of Modified Release Portion

0203The modified release portion can be any formulation that provides the desired in vitro dissolution profile of gamma-hydroxybutyrate. The modified release portion is preferably comprised of modified release particles, obtained by coating immediate release particles of gamma-hydroxybutyrate with a coating (or coating film) that inhibits the immediate release of the gamma-hydroxybutyrate. In one sub-embodiment the modified release portion comprises particles comprising: (a) an inert core; (b) a coating; and (c) a layer comprising the gamma hydroxybutyrate interposed between the core and the coating.

0204In a preferred embodiment, the modified release portion comprises a time-dependent release mechanism and a pH-dependent release mechanism.

0205In a preferred embodiment, the coating film comprises at least one polymer carrying free carboxylic groups, and at least one hydrophobic compound preferably characterized by a melting point equal or greater than 40°C.

0206The polymer carrying free carboxylic groups is preferably selected from: (meth)acrylic acid/alkyl (meth)acrylate copolymers or methacrylic acid and methylmethacrylate copolymers or methacrylic acid and ethyl acrylate copolymers or methacrylic acid copolymers type A, B or C, cellulose derivatives carrying free carboxylic groups, preferably cellulose acetate phthalate, cellulose acetate succinate, hydroxypropyl methyl cellulose phthalate, carboxymethylethyl cellulose, cellulose acetate trimellitate, hydroxypropyl methyl cellulose acetate succinate, polyvinyl acetate phthalate, zein, shellac, alginate and mixtures thereof.

0207In a preferred embodiment, the methacrylic acid copolymers are chosen from the group consisting of poly (methacrylic acid, methyl methacrylate) 1:1 or Eudragit^™ L100 or equivalent, poly (methacrylic acid, ethyl acrylate) 1:1 or Eudragit^™ L100-55 or equivalent and poly (methacrylic acid, methyl methacrylate) 1:2 or Eudragit^™ S100 or equivalent.

0208In a preferred embodiment, the polymer carrying free carboxylic groups is selected from the group consisting of copolymers of methacrylic acid and ethyl acrylate 1:1, copolymers of methacrylic acid and methylmethacrylate 1:2, and mixtures thereof.

0209In another subembodiment the coating comprises a polymer carrying free carboxylic groups wherein the free carboxylic groups are substantially ionized at pH 7.5.

0210The hydrophobic compound with a melting point equal or greater than 40°C can be selected from the group consisting of hydrogenated vegetable oils, vegetable waxes, wax yellow, wax white, wax microcrystalline, lanolin, anhydrous milk fat, hard fat suppository base, lauroyl macrogol glycerides, polyglyceryl diisostearate, diesters or triesters of glycerol with a fatty acid, and mixtures thereof.

0211Even more preferably, the hydrophobic compound with a melting point equal or greater than 40°C is chosen from the group of following products: hydrogenated cottonseed oil, hydrogenated soybean oil, hydrogenated palm oil, glyceryl behenate, hydrogenated castor oil, candellila wax, tristearin, tripalmitin, trimyristin, yellow wax, hard fat or fat that is useful as suppository bases, anhydrous dairy fats, lanolin, glyceryl palmitostearate, glyceryl stearate, lauryl macrogol glycerides, polyglyceryl diisostearate, diethylene glycol monostearate, ethylene glycol monostearate, omega 3 fatty acids, and mixtures thereof. A particularly preferred subgroup of products comprises hydrogenated cottonseed oil, hydrogenated soybean oil, hydrogenated palm oil, glyceryl behenate, hydrogenated castor oil, candelilla wax, tristearin, tripalmitin, trimyristin, beeswax, hydrogenated poly-1 decene, carnauba wax, and mixtures thereof.

0212In practice, and without this being limiting, it is preferable the hydrophobic compound with a melting point equal or greater than 40°C to be chosen from the group of products sold under the following trademarks: Dynasan^™, Cutina^™, Hydrobase^™, Dub^™, Castorwax^™, Croduret^™, Compritol^™, Sterotex^™, Lubritab^™, Apifil^™, Akofine^™, Softisan^™, Hydrocote^™, Livopol^™, Super Hartolan^™, MGLA^™, Corona^™, Protalan^™, Akosoft^™, Akosol^™, Cremao^™, Massupol^™, Novata^™, Suppocire^™, Wecobee^™, Witepsol^™, Lanolin^™, Incromega^™, Estaram^™, Suppoweiss^™, Gelucire^™, Precirol^™, Emulcire^™, Plurol diisostéarique^™, Geleol^™, Hydrine^™, Monthyle^™, Kahlwax^™ and mixtures thereof; and, preferably, from the group of products sold under the following trademarks: Dynasan^™P60, Dynasan^™114, Dynasan^™116, Dynasan^™118, Cutina^™ HR, Hydrobase^™ 66-68, Dub^™ HPH, Compritol^™ 888, Sterotex^™ NF, Sterotex^™ K, Lubritab^™, and mixtures thereof.

0213A particularly suitable coating is composed of a mixture of hydrogenated vegetable oil and a methacrylic acid copolymer. The exact structure and amount of each component, and the amount of coating applied to the particle, controls the release rate and release triggers. Eudragit^® methacrylic acid copolymers, namely the methacrylic acid - methyl methacrylate copolymers and the methacrylic acid - ethyl acrylate copolymers, have a pH-dependent solubility: typically, the pH triggering the release of the active ingredient from the microparticles is set by the choice and mixture of appropriate Eudragit^® polymers. In the case of gamma hydroxybutyrate modified release microparticles, the theoretical pH triggering the release is preferably from 5.5 to 6.97 or 6.9, more preferably 6.5 up to 6.9. By "pH trigger" is meant the minimum pH above which dissolution of the polymer occurs.

0214In a particular embodiment, the coating comprises a hydrophobic compound with a melting point equal or greater than 40°C and a polymer carrying free carboxylic groups are present in a weight ratio from 0.4 or 0.5 to 4, preferably from 0.6 or 0.67 to 2.5, most preferably from 0.6 or 0.67 to 2.33; most preferably about 1.5.

0215A particularly suitable coating is composed of a mixture of hydrogenated vegetable oil and a methacrylic acid copolymer with a theoretical pH triggering the release from 6.5 up to 6.97 in a weight ratio from 0.4 or 0.5 to 4, preferably from 0.6 or 0.67 to 2.5, most preferably from 0.6 or 0.67 to 2.33; most preferably of about 1.5.

0216The modified release particles of gamma-hydroxybutyrate preferably have a volume mean diameter of from 100 to 1200 microns, from 100 to 500 microns, from 200 to 800 microns, and preferably of about 320 microns.

0217The coating can preferably represent 10 to 50%, 15 to 45%, 20 to 40%, or 25 to 35% by weight of the total weight of the coated modified release particles. Preferably, the coating represents 25-30% by weight of the total weight of the modified release particles of gamma-hydroxybutyrate.

0218In a preferred embodiment, the coating layer of the modified release particles of gamma-hydroxybutyrate is obtained by spraying, in particular in a fluidized bed apparatus, a solution, suspension or dispersion comprising the coating composition as defined previously onto the immediate release particles of gamma-hydroxybutyrate, in particular the immediate release particles of gamma-hydroxybutyrate as previously described. Preferably, the coating is formed by spraying in a fluidized bed equipped with a Wurster or partition tube and according to an upward spray orientation or bottom spray a solution of the coating excipients in hot isopropyl alcohol.

0219According to a preferred embodiment, the modified release particles of gamma-hydroxybutyrate consist of 10.5 % w/w of microcrystalline cellulose spheres with a volume mean diameter of about 95 microns to about 450 microns, layered with 56.5% w/w of gamma-hydroxybutyrate mixed with 3% w/w of Povidone^™ K30 and finally coated with a coating composition consisting of 18% w/w of hydrogenated vegetable oil (Lubritab^™ or equivalent), 4% of methacrylic acid copolymer type C (Eudragit^™ L100-55 or equivalent) and 8% of methacrylic acid copolymer type B (Eudragit^™ S100 or equivalent), all percentages expressed based on the total weight of the final modified release particles of gamma-hydroxybutyrate.

0220According to a preferred embodiment, the modified release particles of gamma-hydroxybutyrate consist of 10.5 % w/w of microcrystalline cellulose spheres with a volume mean diameter of about 95 microns to about 170 microns, layered with 56.5% w/w of gamma-hydroxybutyrate mixed with 3% w/w of Povidone^™ K30 and finally coated with a coating composition consisting of 18% w/w of hydrogenated vegetable oil (Lubritab^™ or equivalent), 4% of methacrylic acid copolymer type C (Eudragit^™ L100-55 or equivalent) and 8% of methacrylic acid copolymer type B (Eudragit^™ S100 or equivalent), all percentages expressed based on the total weight of the final modified release particles of gamma-hydroxybutyrate.

0221According to a preferred embodiment, the modified release particles of gamma-hydroxybutyrate consist of 10.5 % w/w of microcrystalline cellulose spheres with a volume mean diameter of about 95 microns to about 450 microns, layered with 56.5% w/w of sodium oxybate mixed with 3% w/w of Povidone^™ K30 and finally coated with a coating composition consisting of 18% w/w of hydrogenated vegetable oil (Lubritab^™ or equivalent), 4% of methacrylic acid copolymer type C (Eudragit^™ L100-55 or equivalent) and 8% of methacrylic acid copolymer type B (Eudragit^™ S100 or equivalent), all percentages expressed based on the total weight of the final modified release particles of sodium oxybate.

0222According to a preferred embodiment, the modified release particles of gamma-hydroxybutyrate consist of 10.5 % w/w of microcrystalline cellulose spheres with a volume mean diameter of about 95 microns to about 170 microns, layered with 56.5% w/w of sodium oxybate mixed with 3% w/w of Povidone^™ K30 and finally coated with a coating composition consisting of 18% w/w of hydrogenated vegetable oil (Lubritab^™ or equivalent), 4% of methacrylic acid copolymer type C (Eudragit^™ L100-55 or equivalent) and 8% of methacrylic acid copolymer type B (Eudragit^™ S100 or equivalent), all percentages expressed based on the total weight of the final modified release particles of sodium oxybate.

0223According to another preferred embodiment, the modified release particles of gamma-hydroxybutyrate consist of 11.3% w/w of microcrystalline cellulose spheres with a volume mean diameter of about 95 microns to about 450 microns, layered with 60.5% w/w of gamma-hydroxybutyrate mixed with 3.2% w/w of Povidone^™ K30 and finally coated with a coating composition consisting of 15 % w/w of hydrogenated vegetable oil (Lubritab^™ or equivalent), 0.75% of methacrylic acid copolymer type C (Eudragit^™ L100-55 or equivalent) and 9.25% of methacrylic acid copolymer type B (Eudragit^™ S100 or equivalent).

0224According to another preferred embodiment, the modified release particles of gamma-hydroxybutyrate consist of 11.3% w/w of microcrystalline cellulose spheres with a volume mean diameter of about 95 microns to about 170 microns, layered with 60.5% w/w of gamma-hydroxybutyrate mixed with 3.2% w/w of Povidone^™ K30 and finally coated with a coating composition consisting of 15 % w/w of hydrogenated vegetable oil (Lubritab^™ or equivalent), 0.75% of methacrylic acid copolymer type C (Eudragit^™ L100-55 or equivalent) and 9.25% of methacrylic acid copolymer type B (Eudragit^™ S100 or equivalent).

0225According to another preferred embodiment, the modified release particles of gamma-hydroxybutyrate consist of 11.3% w/w of microcrystalline cellulose spheres with a volume mean diameter of about 95 microns to about 450 microns, layered with 60.5% w/w of sodium oxybate mixed with 3.2% w/w of Povidone^™ K30 and finally coated with a coating composition consisting of 15 % w/w of hydrogenated vegetable oil (Lubritab^™ or equivalent), 0.75% of methacrylic acid copolymer type C (Eudragit^™ L100-55 or equivalent) and 9.25% of methacrylic acid copolymer type B (Eudragit^™ S100 or equivalent).

0226According to another preferred embodiment, the modified release particles of gamma-hydroxybutyrate consist of 11.3% w/w of microcrystalline cellulose spheres with a volume mean diameter of about 95 microns to about 170 microns, layered with 60.5% w/w of sodium oxybate mixed with 3.2% w/w of Povidone^™ K30 and finally coated with a coating composition consisting of 15 % w/w of hydrogenated vegetable oil (Lubritab^™ or equivalent), 0.75% of methacrylic acid copolymer type C (Eudragit^™ L100-55 or equivalent) and 9.25% of methacrylic acid copolymer type B (Eudragit^™ S100 or equivalent).

Packaging

0227The modified release formulation of gamma-hydroxybutyrate is preferably supplied in sachets or stick-packs comprising a particulate formulation. The sachets are preferably available in several different doses, comprising gamma-hydroxybutyrate in amounts equivalents to 0.5 g, 1.0 g, 1.5 g, 3.0 g, 4.5 g, 6.0 g, 7.5 g, 9.0 g, 10.5 g and/or 12g of sodium oxybate. Depending on the dose required, one or more of these sachets can be opened, and its contents mixed with tap water to provide the nightly dose of gamma-hydroxybutyrate.

Methods of Treatment

0228The invention further provides a method of treating a disorder treatable with gamma-hydroxybutyrate in a human subject in need thereof comprising orally administering a single bedtime daily dose to said human amounts of gamma-hydroxybutyrate equivalent to from 3.0 to 12.0 g of sodium oxybate in the formulation of the present invention. The invention further provides methods of treating narcolepsy, types 1 and/or 2, by orally administering at bedtime a therapeutically effective amount of a gamma-hydroxybutyrate formulation characterized by the novel gamma-hydroxybutyrate pharmacokinetics or dissolution properties of the present invention. The modified release formulation of the present invention is effective to treat narcolepsy Type 1 or Type 2, wherein said treatment of narcolepsy is defined as reducing excessive daytime sleepiness or reducing the frequency of cataplectic attacks. The therapeutically effective amount preferably comprises equivalents from 3.0 to 12.0 g of sodium oxybate, more preferably from to 9.0 g of sodium oxybate, and most preferably 4.5, 6.0, 7.5 or 9.0 g of sodium oxybate. The effectiveness of the treatment can be measured by one or any combination of the following criteria: <ul id="ul0005" list-style="bullet" compact="compact"><li>Increase the mean sleep latency, preferably as determined on the Maintenance of Wakefulness Test (MWT)</li><li>Improve the Clinical Global Impression (CGI) rating of sleepiness</li><li>Decrease the number of cataplexy attacks (NCA) preferably determined from the cataplexy frequency item in the Sleep and Symptoms Daily Diary</li><li>Decrease the disturbed nocturnal sleep (DNS), the disturbed nocturnal events or the adverse respiratory events preferably as determined by polysomnographic (PSG) measures of sleep fragmentation</li><li>Decrease the excessive daytime sleepiness (EDS) preferably as measured by patient report via the Epworth Sleepiness Scale (ESS)</li><li>Decrease the daytime sleepiness as measured by the Maintenance of Wakefulness Test based on EEG measures of wakefulness</li><li>Decrease PSG transitions from N/2 to N/3 and REM sleep to wake and N1 sleep (as determined by <nplcit id="ncit0004" npl-type="s"><text>C Iber, S Ancoli-Israel, A Chesson, SF Quan. The AASM Manual for the Scoring of Sleep and Associated Events.</text></nplcit><nplcit id="ncit0005" npl-type="s"><text>Westchester, IL: American Academy of Sleep Medicine; 2007</text></nplcit>).</li><li>Decrease the number of arousals or wakenings, preferably obtained from a PSG as defined by the American Academy of Sleep Medicine</li><li>Improve the sleep quality, preferably obtained from one or more of (i) the Sleep and Symptom Daily Diary, (ii) Visual Analog Scale (VAS) for sleep quality and sleep diary, and (iii) VAS for the refreshing nature of sleep</li><li>Decrease the Hypnagogic Hallucinations (HH) or sleep paralysis (SP) symptoms in NT1 narcolepsy patients, preferably as measured by the Sleep and Symptom Daily Diary</li></ul>

0229Another object of the present invention is a modified release formulation of the present invention for use in the treatment of a disorder treatable with sodium oxybate in a human subject in need thereof, said formulation being orally administered in a single bedtime daily dose to said human equivalent to 3.0 to 12.0 g of sodium oxybate.

0230Another object of the present invention is a modified release formulation of the present invention for use in the treatment of cataplexy in narcolepsy or excessive daytime sleepiness ("EDS") in narcolepsy, said formulation being orally administered a single bedtime daily dose to said human subject equivalent to 3.0 to 12.0 g of sodium oxybate.

0231In particular, the administration of said modified release formulation of gamma-hydroxybutyrate, compared to a dosing regimen consisting of administering half the dose at t₀ and another half of the dose at t_4h in an immediate release liquid solution, has been shown to <ol id="ol0014" compact="compact"><li>a) decrease the number of cataplectic attacks;</li><li>b) decrease daytime sleepiness when measured on the Epworth Sleepiness Scale;</li><li>c) decrease daytime sleepiness as measured by the Maintenance of Wakefulness Test based on EEG measures of wakefulness;</li><li>d) improve said subject's Clinical Global Impression (CGI) rating of sleepiness;</li><li>e) decrease disturbed nocturnal events or adverse respiratory events as determined by polysomnogram (PSG);</li><li>f) decrease hypnagogic hallucinations;</li><li>g) decrease sleep paralysis;</li><li>h) increase MWT sleep latency;</li><li>i) decrease PSG transitions from N2 to N3 and REM sleep to wake and N1 sleep;</li><li>j) decrease number of arousals in NT1 and/or NT2 subjects obtained from a PSG;</li><li>k) improve sleep quality and refreshing nature of sleep in NT1 and/or NT2 subjects as measured on Visual Analog Scale (VAS);</li><li>l) decrease the number of wakenings; or</li><li>m) any combination thereof.</li></ol>

0232In a preferred embodiment, the treatment of the present invention is superior, as measured by any one or combination of the foregoing criteria, to an equal dose administered twice nightly of an immediate release liquid solution of sodium oxybate, with the second dose administered 4 hours after the first dose.

0233The invention further provides a method of treatment of narcolepsy Type 1 or Type 2 wherein, compared to a dosing regimen consisting of administering half the dose at t₀ and another half of the dose at t_4h of an immediate release liquid solution of sodium oxybate, a single bedtime daily dose administration of a therapeutically effective amount of the formulation of the invention has been shown to produce less confusion, less depressive syndrome, less incontinence, less nausea or less sleepwalking.

Additional embodiments

0234In one additional embodiment, the invention provides a modified release formulation of gamma-hydroxybutyrate, preferably comprising immediate release and modified release portions, wherein the formulation releases (a) at least 80% of its gamma-hydroxybutyrate at 1 hour when tested in a dissolution apparatus 2 according to USP 38 <711> in 900 mL of 0.05M monobasic potassium phosphate buffer pH 6.8 at a temperature of 37° C and a paddle speed of 75 rpm, and (b) from 10% to 65%, of its gamma-hydroxybutyrate at one hour and three hours when tested in a dissolution apparatus 2 according to USP 38 <711> in 900 mL of 0.1N hydrochloric acid at a temperature of 37°C and a paddle speed of 75 rpm.

0235In a second additional embodiment, the invention provides a modified release formulation of gamma-hydroxybutyrate, comprising immediate release and modified release portions, wherein (a) the formulation releases at least 80% of its gamma-hydroxybutyrate at 1 hour when tested in a dissolution apparatus 2 according to USP 38 <711> in 900 mL of 0.05M monobasic potassium phosphate buffer pH 6.8 at a temperature of 37° C and a paddle speed of 75 rpm, (b) the formulation releases from 10% to 65% of its gamma-hydroxybutyrate at one hour and three hours when tested in a dissolution apparatus 2 according to USP 38 <711> in 900 mL of 0.1N hydrochloric acid at a temperature of 37°C and a paddle speed of 75 rpm, and (c) the modified release portion releases greater than 80% of its gamma-hydroxybutyrate at 3 hours in a dissolution test started in 750 mL of 0.1N hydrochloric acid for 2 hours then switched to 950 mL 0.05M monobasic potassium phosphate buffer adjusted to pH 6.8 at a temperature of 37°C and a paddle speed of 75 rpm.

0236In a third additional embodiment, the invention provides a modified release formulation of gamma-hydroxybutyrate, comprising immediate release and modified release portions, wherein (a) the formulation releases at least 80% of its gamma-hydroxybutyrate at 1 hour when tested in a dissolution apparatus 2 according to USP 38 <711> in 900 mL of 0.05M monobasic potassium phosphate buffer pH 6.8 at a temperature of 37° C and a paddle speed of 75 rpm, (b) the formulation releases 10% to 65%, of its gamma-hydroxybutyrate at one hour and at three hours when tested in a dissolution apparatus 2 according to USP 38 <711> in 900 mL of 0.1N hydrochloric acid at a temperature of 37°C and a paddle speed of 75 rpm, (c) the formulation releases greater than 60% of its gamma-hydroxybutyrate at 10 hours when tested in a dissolution apparatus 2 according to USP 38 <711> in 900 mL of 0.1N hydrochloric acid at a temperature of 37°C and a paddle speed of 75 rpm, and (d) the modified release portion releases greater than 80% of its gamma-hydroxybutyrate at 3 hours in a dissolution test started in 750 mL of 0.1N hydrochloric acid for 2 hours then switched to 950 mL 0.05M monobasic potassium phosphate buffer adjusted to pH 6.8 at a temperature of 37°C and a paddle speed of 75 rpm.

0237In a fourth additional embodiment, the invention provides a modified release formulation of gamma-hydroxybutyrate, preferably comprising immediate release and modified release portions, wherein the formulation releases (a) at least 80% of its gamma-hydroxybutyrate at 3 hours when tested in a dissolution apparatus 2 according to USP 38 <711> in 900 mL of 0.05M monobasic potassium phosphate buffer pH 6.8 at a temperature of 37° C and a paddle speed of 75 rpm, and (b) from 40% to 65%, of its gamma-hydroxybutyrate at one hour and three hours when tested in a dissolution apparatus 2 according to USP 38 <711> in 900 mL of 0.1N hydrochloric acid at a temperature of 37°C and a paddle speed of 75 rpm.

0238In a fifth additional embodiment, the invention provides a modified release formulation of gamma-hydroxybutyrate, comprising immediate release and modified release portions, wherein (a) the formulation releases at least 80% of its gamma-hydroxybutyrate at 3 hour3 when tested in a dissolution apparatus 2 according to USP 38 <711> in 900 mL of 0.05M monobasic potassium phosphate buffer pH 6.8 at a temperature of 37° C and a paddle speed of 75 rpm, (b) the formulation releases from 40% to 65% of its gamma-hydroxybutyrate at one hour and three hours when tested in a dissolution apparatus 2 according to USP 38 <711> in 900 mL of 0.1N hydrochloric acid at a temperature of 37°C and a paddle speed of 75 rpm, and (c) the modified release portion releases greater than 80% of its gamma-hydroxybutyrate at 3 hours in a dissolution test started in 750 mL of 0.1N hydrochloric acid for 2 hours then switched to 950 mL 0.05M monobasic potassium phosphate buffer adjusted to pH 6.8 at a temperature of 37°C and a paddle speed of 75 rpm.

0239In a sixth additional embodiment, the invention provides a modified release formulation of gamma-hydroxybutyrate, comprising immediate release and modified release portions, wherein (a) the formulation releases at least 80% of its gamma-hydroxybutyrate at 3 hours when tested in a dissolution apparatus 2 according to USP 38 <711> in 900 mL of 0.05M monobasic potassium phosphate buffer pH 6.8 at a temperature of 37° C and a paddle speed of 75 rpm, (b) the formulation releases 40% to 65%, of its gamma-hydroxybutyrate at one hour and at three hours when tested in a dissolution apparatus 2 according to USP 38 <711> in 900 mL of 0.1N hydrochloric acid at a temperature of 37°C and a paddle speed of 75 rpm, (c) the formulation releases greater than 60% of its gamma-hydroxybutyrate at 10 hours when tested in a dissolution apparatus 2 according to USP 38 <711> in 900 mL of 0.1N hydrochloric acid at a temperature of 37°C and a paddle speed of 75 rpm, and (d) the modified release portion releases greater than 80% of its gamma-hydroxybutyrate at 3 hours in a dissolution test started in 750 mL of 0.1N hydrochloric acid for 2 hours then switched to 950 mL 0.05M monobasic potassium phosphate buffer adjusted to pH 6.8 at a temperature of 37°C and a paddle speed of 75 rpm.

0240In a seventh additional embodiment, the invention provides a modified release formulation of gamma-hydroxybutyrate, preferably comprising immediate release and modified release portions, wherein the formulation releases (a) at least 80% of its gamma-hydroxybutyrate at 1 hour when tested in a dissolution apparatus 2 according to USP 38 <711> in 900 mL of 0.05M monobasic potassium phosphate buffer pH 6.8 at a temperature of 37° C and a paddle speed of 75 rpm, and (b) from 40% to 65%, of its gamma-hydroxybutyrate at one hour and three hours when tested in a dissolution apparatus 2 according to USP 38 <711> in 900 mL of 0.1N hydrochloric acid at a temperature of 37°C and a paddle speed of 75 rpm.

0241In a eighth additional embodiment, the invention provides a modified release formulation of gamma-hydroxybutyrate, comprising immediate release and modified release portions, wherein (a) the formulation releases at least 80% of its gamma-hydroxybutyrate at 1 hour when tested in a dissolution apparatus 2 according to USP 38 <711> in 900 mL of 0.05M monobasic potassium phosphate buffer pH 6.8 at a temperature of 37° C and a paddle speed of 75 rpm, (b) the formulation releases from 40% to 65% of its gamma-hydroxybutyrate at one hour and three hours when tested in a dissolution apparatus 2 according to USP 38 <711> in 900 mL of 0.1N hydrochloric acid at a temperature of 37°C and a paddle speed of 75 rpm, and (c) the modified release portion releases greater than 80% of its gamma-hydroxybutyrate at 3 hours in a dissolution test started in 750 mL of 0.1N hydrochloric acid for 2 hours then switched to 950 mL 0.05M monobasic potassium phosphate buffer adjusted to pH 6.8 at a temperature of 37°C and a paddle speed of 75 rpm.

0242In a ninth additional embodiment, the invention provides a modified release formulation of gamma-hydroxybutyrate, comprising immediate release and modified release portions, wherein (a) the formulation releases at least 80% of its gamma-hydroxybutyrate at 1 hour when tested in a dissolution apparatus 2 according to USP 38 <711> in 900 mL of 0.05M monobasic potassium phosphate buffer pH 6.8 at a temperature of 37° C and a paddle speed of 75 rpm, (b) the formulation releases 40 to 65%, of its gamma-hydroxybutyrate at one hour and at three hours when tested in a dissolution apparatus 2 according to USP 38 <711> in 900 mL of 0.1N hydrochloric acid at a temperature of 37°C and a paddle speed of 75 rpm, (c) the formulation releases greater than 60% of its gamma-hydroxybutyrate at 10 hours when tested in a dissolution apparatus 2 according to USP 38 <711> in 900 mL of 0.1N hydrochloric acid at a temperature of 37°C and a paddle speed of 75 rpm, and (d) the modified release portion releases greater than 80% of its gamma-hydroxybutyrate at 3 hours in a dissolution test started in 750 mL of 0.1N hydrochloric acid for 2 hours then switched to 950 mL 0.05M monobasic potassium phosphate buffer adjusted to pH 6.8 at a temperature of 37°C and a paddle speed of 75 rpm.

<u>EXAMPLES</u>

EXAMPLE 1. FORMULATIONS

0243Tables 1a-1d provide the qualitative and quantitative compositions of sodium oxybate IR microparticles, MR microparticles, and mixtures of IR and MR microparticles. The physical structure of the microparticles showing the qualitative and quantitative composition of the IR and MR microparticles is depicted in <figref idref="f0001">Figure 1</figref>.

0244Briefly, sodium oxybate immediate release (IR) microparticles were prepared as follows: 1615.0 g of sodium oxybate and 85.0 g of polyvinylpyrrolidone (Povidone K30-Plasdone^™ K29/32 from ISP) were solubilized in 1894.3 g of absolute ethyl alcohol and 1262.9 g of water. The solution was entirely sprayed onto 300 g of microcrystalline cellulose spheres (Cellets^™ 127) in a fluid bed spray coater apparatus. IR Microparticles with volume mean diameter of about 270 microns were obtained.

0245Sodium oxybate modified release (MR) microparticles were prepared as follows: 22.8 g of methacrylic acid copolymer Type C (Eudragit^™ L100-55), 45.8 g of methacrylic acid copolymer Type B (Eudragit^™ S100), 102.9 g of hydrogenated cottonseed oil (Lubritab^™), were dissolved in 1542.9 g of isopropanol at 78°C. The solution was sprayed entirely onto 400.0 g of the sodium oxybate IR microparticles described above in a fluid bed spray coater apparatus with an inlet temperature of 48° C, spraying rate around 11 g per min and atomization pressure of 1.3 bar. MR microparticles were dried for two hours with inlet temperature set to 56°C. MR microparticles with mean volume diameter of about 320 microns were obtained.

0246The finished composition, which contains a 50:50 mixture of MR and IR microparticles calculated on their sodium oxybate content, was prepared as follows: 353.36 g of the above IR microparticles, 504.80 g of the above MR microparticles, 14.27 g of malic acid (D/L malic acid), 6.34 g of xanthan gum (Xantural^™ 75 from Kelco), 9.51 g of carrageenan gum (Viscarin^™ PH209 from FMC Biopolymer), 9.51 g of hydroxyethylcellulose (Natrosol^™ 250M from Ashland) and 4.51 g of magnesium stearate were mixed. Individual samples of 7.11g (corresponding to a 4.5g dose of sodium oxybate with half of the dose as immediate-release fraction and half of the dose as modified release fraction) were weighed. <tables id="tabl0004" num="0004"><table frame="all"><title>Table 1a: Composition of IR Microparticles</title><tgroup cols="3"><colspec colnum="1" colname="col1" colwidth="53mm" /><colspec colnum="2" colname="col2" colwidth="62mm" /><colspec colnum="3" colname="col3" colwidth="47mm" /><thead valign="top"><row><entry>Component</entry><entry>Function</entry><entry>Quantity per 2.25 g dose (g)</entry></row></thead><tbody><row><entry>Sodium oxybate</entry><entry>Drug substance</entry><entry>2.25</entry></row><row><entry>Microcrystalline cellulose spheres</entry><entry>Core</entry><entry>0.418</entry></row><row><entry>Povidone K30</entry><entry>Binder and excipient in diffusion coating</entry><entry>0.118</entry></row><row><entry>Ethyl alcohol</entry><entry>Solvent</entry><entry>Eliminated during processing</entry></row><row><entry>Purified water</entry><entry>Solvent</entry><entry>Eliminated during processing</entry></row><row><entry>Total</entry><entry /><entry>2.786</entry></row></tbody></tgroup></table></tables><tables id="tabl0005" num="0005"><table frame="all"><title>Table 1b: Composition of MR Microparticles</title><tgroup cols="3"><colspec colnum="1" colname="col1" colwidth="56mm" /><colspec colnum="2" colname="col2" colwidth="43mm" /><colspec colnum="3" colname="col3" colwidth="47mm" /><thead valign="top"><row><entry>Component</entry><entry>Function</entry><entry>Quantity per 4.5 g dose (g)</entry></row></thead><tbody><row><entry>IR Microparticles</entry><entry>Core of MR microparticles</entry><entry>2.786</entry></row><row><entry>Hydrogenated Vegetable Oil</entry><entry>Coating excipient</entry><entry>0.716</entry></row><row><entry>Methacrylic acid Copolymer Type C</entry><entry>Coating excipient</entry><entry>0.159</entry></row><row><entry>Methacrylic acid Copolymer Type B</entry><entry>Coating excipient</entry><entry>0.318</entry></row><row><entry>Isopropyl alcohol</entry><entry>Solvent</entry><entry>Eliminated during processing</entry></row><row><entry>Total</entry><entry /><entry>3.981</entry></row></tbody></tgroup></table></tables><tables id="tabl0006" num="0006"><table frame="all"><title>Table 1c: Qualitative Finished Composition</title><tgroup cols="3"><colspec colnum="1" colname="col1" colwidth="37mm" /><colspec colnum="2" colname="col2" colwidth="70mm" /><colspec colnum="3" colname="col3" colwidth="44mm" /><thead valign="top"><row><entry>Component</entry><entry>Function</entry><entry>Quantity per 4.5 g dose (g)</entry></row></thead><tbody><row><entry>MR microparticles</entry><entry>Modified release fraction of sodium oxybate</entry><entry>3.981</entry></row><row valign="bottom"><entry>IR microparticles</entry><entry>Immediate release fraction of sodium oxybate</entry><entry>2.786</entry></row><row><entry>Malic acid</entry><entry>Acidifying agent</entry><entry>0.113</entry></row><row><entry>Xanthan gum</entry><entry>Suspending agent</entry><entry>0.050</entry></row><row><entry>Hydroxyethylcellulose</entry><entry>Suspending agent</entry><entry>0.075</entry></row><row><entry>Carrageenan gum</entry><entry>Suspending agent</entry><entry>0.075</entry></row><row><entry valign="bottom">Magnesium stearate</entry><entry>Lubricant</entry><entry>0.036</entry></row><row><entry>Total</entry><entry /><entry>7.116</entry></row></tbody></tgroup></table></tables><tables id="tabl0007" num="0007"><table frame="all"><title>Table 1d: Quantitative finished composition</title><tgroup cols="3"><colspec colnum="1" colname="col1" colwidth="56mm" /><colspec colnum="2" colname="col2" colwidth="32mm" /><colspec colnum="3" colname="col3" colwidth="44mm" /><thead valign="top"><row><entry>Component</entry><entry>Function</entry><entry>Quantity per 4.5 g dose (g)</entry></row></thead><tbody><row><entry>Sodium oxybate</entry><entry>Drug substance</entry><entry>4.5</entry></row><row><entry>Microcrystalline cellulose spheres</entry><entry>Core</entry><entry>0.836</entry></row><row><entry>Povidone K30</entry><entry>Binder</entry><entry>0.237</entry></row><row><entry>Hydrogenated Vegetable Oil</entry><entry>Coating excipient</entry><entry>0.716</entry></row><row><entry>Methacrylic acid Copolymer Type C</entry><entry>Coating excipient</entry><entry>0.159</entry></row><row><entry>Methacrylic acid Copolymer Type B</entry><entry>Coating excipient</entry><entry>0.318</entry></row><row><entry>Malic acid</entry><entry>Acidifying agent</entry><entry>0.113</entry></row><row><entry>Xanthan gum</entry><entry>Suspending agent</entry><entry>0.050</entry></row><row><entry>Hydroxyethylcellulose</entry><entry>Suspending agent</entry><entry>0.075</entry></row><row><entry>Carrageenan gum</entry><entry>Suspending agent</entry><entry>0.075</entry></row><row><entry>Magnesium stearate</entry><entry>Lubricant</entry><entry>0.036</entry></row><row><entry>Total</entry><entry /><entry>7.116</entry></row></tbody></tgroup></table></tables>

EXAMPLE IBIS: ALTERNATIVE FORMULATION

0247An alternative formulation to the formulation described in example 1 is described in Example 1bis.

0248Sodium oxybate immediate release (IR) microparticles were prepared by coating the IR microparticles described in example 1 with a top coat layer. Microparticles were prepared as follows: 170.0 of hydroxypropyl cellulose (Klucel^™ EF Pharm from Hercules) were solubilized in 4080.0g of acetone. The solution was entirely sprayed onto 1530.0g of the IR microparticles of Example 1 in a fluid bed spray coater apparatus. IR Microparticles with volume mean diameter of about 298 microns were obtained (see Table 1bis-a).

0249Sodium oxybate modified release (MR) microparticles were prepared as described in example 1 (see Table 1b).

0250The finished composition, which contains a 50:50 mixture of MR and IR microparticles based on their sodium oxybate content, was prepared as follows: 412.22g of the above IR microparticles, 530.00g of the above MR microparticles, 29.96g of malic acid (D/L malic acid), 4.96g of xanthan gum (Xantural^™ 75 from Kelco), 4.96g of colloidal silicon dioxide (Aerosil^™ 200 from Degussa) and 9.92g of magnesium stearate were mixed. Individual samples of 7.45g (corresponding to a 4.5g dose of sodium oxybate with half of the dose in an immediate-release fraction and half of the dose in a modified release fraction) were weighed (see Table 1bis-b and 1bis-c). <tables id="tabl0008" num="0008"><table frame="all"><title>Table 1bis-a: Composition of IR Microparticles</title><tgroup cols="3"><colspec colnum="1" colname="col1" colwidth="53mm" /><colspec colnum="2" colname="col2" colwidth="62mm" /><colspec colnum="3" colname="col3" colwidth="47mm" /><thead valign="top"><row><entry>Component</entry><entry>Function</entry><entry>Quantity per 2.25 g dose (g)</entry></row></thead><tbody><row><entry>Sodium oxybate</entry><entry>Drug substance</entry><entry>2.25</entry></row><row><entry>Microcrystalline cellulose spheres</entry><entry>Core</entry><entry>0.418</entry></row><row><entry>Povidone K30</entry><entry>Binder and excipient in diffusion coating</entry><entry>0.118</entry></row><row><entry>Hydroxypropyl cellulose</entry><entry>Top coat</entry><entry>0.310</entry></row><row><entry>Ethyl alcohol</entry><entry>Solvent</entry><entry>Eliminated during processing</entry></row><row><entry>Purified water</entry><entry>Solvent</entry><entry>Eliminated during processing</entry></row><row><entry>Acetone</entry><entry>Solvent</entry><entry>Eliminated during processing</entry></row><row><entry>Total</entry><entry /><entry>3.096</entry></row></tbody></tgroup></table></tables><tables id="tabl0009" num="0009"><table frame="all"><title>Table 1bis-b: Qualitative Finished Composition</title><tgroup cols="3"><colspec colnum="1" colname="col1" colwidth="39mm" /><colspec colnum="2" colname="col2" colwidth="70mm" /><colspec colnum="3" colname="col3" colwidth="44mm" /><thead valign="top"><row><entry>Component</entry><entry>Function</entry><entry>Quantity per 4.5 g dose (g)</entry></row></thead><tbody><row><entry>MR microparticles</entry><entry>Modified release fraction of sodium oxybate</entry><entry>3.981</entry></row><row><entry>IR microparticles</entry><entry>Immediate release fraction of sodium oxybate</entry><entry>3.096</entry></row><row><entry>Malic acid</entry><entry>Acidifying agent</entry><entry>0.225</entry></row><row><entry>Xanthan gum</entry><entry>Suspending agent</entry><entry>0.037</entry></row><row><entry>Colloidal silicon dioxide</entry><entry>Gliding agent</entry><entry>0.037</entry></row><row><entry>Magnesium stearate</entry><entry>Lubricant</entry><entry>0.075</entry></row><row><entry>Total</entry><entry /><entry>7.451</entry></row></tbody></tgroup></table></tables><tables id="tabl0010" num="0010"><table frame="all"><title>Table 1bis-c: Quantitative finished composition</title><tgroup cols="3"><colspec colnum="1" colname="col1" colwidth="56mm" /><colspec colnum="2" colname="col2" colwidth="32mm" /><colspec colnum="3" colname="col3" colwidth="44mm" /><thead valign="top"><row><entry>Component</entry><entry>Function</entry><entry>Quantity per 4.5 g dose (g)</entry></row></thead><tbody><row><entry>Sodium oxybate</entry><entry>Drug substance</entry><entry>4.5</entry></row><row><entry>Microcrystalline cellulose spheres</entry><entry>Core</entry><entry>0.836</entry></row><row><entry>Povidone K30</entry><entry>Binder</entry><entry>0.237</entry></row><row><entry>Hydroxypropyl cellulose</entry><entry>Top coat</entry><entry>0.310</entry></row><row><entry>Hydrogenated Vegetable Oil</entry><entry>Coating excipient</entry><entry>0.716</entry></row><row><entry>Methacrylic acid Copolymer Type C</entry><entry>Coating excipient</entry><entry>0.159</entry></row><row><entry>Methacrylic acid Copolymer Type B</entry><entry>Coating excipient</entry><entry>0.318</entry></row><row><entry>Malic acid</entry><entry>Acidifying agent</entry><entry>0.225</entry></row><row><entry>Xanthan gum</entry><entry>Suspending agent</entry><entry>0.037</entry></row><row><entry>Colloidal silicon dioxide</entry><entry>Gliding agent</entry><entry>0.037</entry></row><row><entry>Magnesium stearate</entry><entry>Lubricant</entry><entry>0.075</entry></row><row><entry>Total</entry><entry /><entry>7.451</entry></row></tbody></tgroup></table></tables>

0251Compared to the finished composition described in example 1, this alternative composition has the following characteristics: same MR microparticles, same IR microparticles but with a top coat, increased amount of malic acid, only one suspending agent (xanthan gum) and presence ofa glidant.

0252Finished compositions from Example 1 and 1bis exhibit substantially the same in-vitro dissolution profiles (see <figref idref="f0004">figures 7 and 8</figref>).

EXAMPLE 2: IN VITRO RELEASE PROFILES OF IR, MR AND FINISHED COMPOSITIONS OF FORMULATIONS OF EXAMPLES 1 AND 1BIS

<u>Dissolution testing of IR</u><u>Microparticles</u>

0253The dissolution profile of 2786 mg of IR microparticles of Example 1, corresponding to 2250mg of sodium oxybate per vessel, was determined in 0.1N HCl dissolution medium using a USP apparatus 2. Dissolution medium temperature was maintained at 37.0 ± 0.5 °C, and the rotating paddle speed was set at 100 rpm. The release profile of the IR microparticles is shown in <figref idref="f0001">Figure 2</figref> and Table 2a. All the sodium oxybate was released at 1hour. <tables id="tabl0011" num="0011"><table frame="all"><title>Table 2a. Percent Sodium Oxybate Released in 0.1N HCl for IR microparticles of sodium oxybate prepared according to Example 1</title><tgroup cols="2"><colspec colnum="1" colname="col1" colwidth="82mm" align="center" /><colspec colnum="2" colname="col2" colwidth="82mm" align="center" /><thead><row><entry valign="middle">Time (min)</entry><entry valign="top">% released</entry></row></thead><tbody valign="middle"><row><entry>0</entry><entry>0</entry></row><row><entry>5</entry><entry>94</entry></row><row><entry>10</entry><entry>97</entry></row><row><entry>15</entry><entry>97</entry></row><row><entry>30</entry><entry>98</entry></row><row><entry>60</entry><entry>98</entry></row></tbody></tgroup></table></tables>

<u>Dissolution testing of IR Microparticles from example</u> 1bis

0254The dissolution profile of 3096 mg of IR microparticles of Example 1bis, corresponding to 2250 mg of sodium oxybate per vessel, was determined in 0.1N HCl dissolution medium using a USP apparatus 2. Dissolution medium temperature was maintained at 37.0 ± 0.5 °C, and the rotating paddle speed was set at 100 rpm. The release profile of the IR microparticles is shown in <figref idref="f0001">Figure 2</figref> and Table 2b. All the sodium oxybate was released at 1hour. <tables id="tabl0012" num="0012"><table frame="all"><title>Table 2b. Percent Sodium Oxybate Released in 0.1N HCl for IR microparticles of sodium oxybate prepared according Example 1bis</title><tgroup cols="2"><colspec colnum="1" colname="col1" colwidth="81mm" align="center" /><colspec colnum="2" colname="col2" colwidth="83mm" align="center" /><thead valign="top"><row><entry>Time (min)</entry><entry>% Released</entry></row></thead><tbody><row><entry>0</entry><entry>0</entry></row><row><entry>5</entry><entry>91</entry></row><row><entry>10</entry><entry>99</entry></row><row><entry>15</entry><entry>100</entry></row><row><entry>30</entry><entry>101</entry></row><row><entry>60</entry><entry>100</entry></row></tbody></tgroup></table></tables>

<i>Dissolution testing of MR Microparticles from Example 1 - protocol (2h 0.1N HCl</i> / <i>phosphate buffer pH 6.8)</i>

025549.1g of MR microparticles from Example 1 were mixed with 0.5g of magnesium stearate (from Peter Graven) and 0.25g of colloidal silicon dioxide (Aerosil^™ 200 from Evonik). The dissolution profile of 4040 mg of the mixture which corresponds to 2250 mg of sodium oxybate per vessel was determined using the USP apparatus 2. Dissolution medium temperature was maintained at 37.0 ± 0.5 °C, and the rotating paddle speed was set at 75 rpm.

0256After 2 hours in 750 mL of 0.1N HCl medium, 6.5g of monobasic potassium phosphate was added to the dissolution vessel. pH and volume were then respectively adjusted to 6.8 and 950 mL, as needed by the addition of NaOH and water. The potassium phosphate concentration was equal to 0.05 M in the dissolution medium after pH and volume adjustment.

0257The release profile of the MR microparticles is shown in <figref idref="f0002">Figure 3</figref> and Table 2c. The sodium oxybate was not released in the 0.1N HCl dissolution medium during two hours. After the switch to pH 6.8 dissolution medium, all the sodium oxybate was released within 30 minutes. <tables id="tabl0013" num="0013"><table frame="all"><title>Table 2c. Percent Sodium Oxybate Released in two sequential dissolution media (0.1HCl for 2 hours, then phosphate buffer pH 6.8) for MR microparticles of sodium oxybate prepared according to Example 1</title><tgroup cols="2"><colspec colnum="1" colname="col1" colwidth="80mm" align="center" /><colspec colnum="2" colname="col2" colwidth="84mm" align="center" /><thead valign="top"><row><entry>Time (h)</entry><entry>% released</entry></row></thead><tbody><row><entry>0</entry><entry>0</entry></row><row><entry>1</entry><entry>1</entry></row><row><entry>2</entry><entry>2</entry></row><row><entry>2.25</entry><entry>33</entry></row><row><entry>2,5</entry><entry>97</entry></row><row><entry>3</entry><entry>103</entry></row><row><entry>4</entry><entry>104</entry></row><row><entry>6</entry><entry>103</entry></row></tbody></tgroup></table></tables>

0258<figref idref="f0002">Figure 4</figref> overlays the dissolution profile of the MR microparticles of Example 1 with the dissolution profile for MR microparticles reported in Supernus <patcit id="pcit0014" dnum="US8193211B"><text>USP 8,193,211</text></patcit>, <figref idref="f0002">figure 3</figref>. It shows that the dissolution profiles are different and that the MR microparticles according to the present invention release greater than 80% of their sodium oxybate at 3 hours, whereas the MR microparticles described in Supernus <patcit id="pcit0015" dnum="US8193211B"><text>USP 8,193,211</text></patcit>, <figref idref="f0002">figure 3</figref> do not and exhibit a much slower release profile.

<u>Dissolution testing of finished composition according to Example 1 in deionized water</u>

0259The dissolution profile of the quantity equivalent to 4.5g sodium oxybate of the finished composition according Example 1 was determined in 900 mL of deionized water using the USP apparatus 2. The dissolution medium was maintained at 37.0 ± 0.5 °C and the rotating paddle speed was fixed at 50 rpm. The release profile is shown in <figref idref="f0003">Figure 5</figref> and Table 2d. The IR fraction of sodium oxybate was solubilized in 15 minutes. The release of sodium oxybate from the modified-release fraction started after approximately 4 hours with 90% of the total dose released at 6 hours. <tables id="tabl0014" num="0014"><table frame="all"><title>Table 2d. Percent Sodium Oxybate Released in deionized water for finished composition of sodium oxybate prepared according to Example 1</title><tgroup cols="2"><colspec colnum="1" colname="col1" colwidth="80mm" align="center" /><colspec colnum="2" colname="col2" colwidth="84mm" align="center" /><thead valign="top"><row><entry>Time (h)</entry><entry>% released</entry></row></thead><tbody><row><entry>0</entry><entry>0</entry></row><row><entry>0,25</entry><entry>53</entry></row><row><entry>1</entry><entry>52</entry></row><row><entry>2</entry><entry>54</entry></row><row><entry>3</entry><entry>55</entry></row><row><entry>4</entry><entry>58</entry></row><row><entry>5</entry><entry>69</entry></row><row><entry>6</entry><entry>92</entry></row><row><entry>7</entry><entry>96</entry></row><row><entry>8</entry><entry>97</entry></row></tbody></tgroup></table></tables>

0260An overlay of the release profile of the finished formulation of Example 1 versus that reported in <patcit id="pcit0016" dnum="US20120076865A"><text>USP 2012/0076865</text></patcit><figref idref="f0001">Figure 2</figref> is shown in <figref idref="f0003">Figure 6</figref>. It shows that the dissolution profiles are different. The formulation described in <patcit id="pcit0017" dnum="US20120076865A"><text>USP 2012/0076865</text></patcit><figref idref="f0001">figure 2</figref> does not exhibit a lag phase after the dissolution of the immediate release part.

<u>Release Testing of Different Batches of MR Microparticles and Finished Dosage Forms</u>

0261In vitro release profiles obtained in 900 mL of 0.1N HCl dissolution medium for different batches of modified release (MR) microparticles prepared according to Example 1 are described below in Table 2e. The dissolution profile of 4040 mg of microparticles corresponding to 2250 mg of sodium oxybate per vessel is determined using the USP apparatus 2. Dissolution medium temperature was maintained at 37.0 ± 0.5 °C, and the rotating paddle speed was set at 100 rpm. <tables id="tabl0015" num="0015"><table frame="all"><title>Table 2e. Percent Sodium Oxybate Released in 0.1 N HCl Dissolution Medium from different manufacturing lots of MR Particles of Example 1</title><tgroup cols="9"><colspec colnum="1" colname="col1" colwidth="17mm" /><colspec colnum="2" colname="col2" colwidth="18mm" /><colspec colnum="3" colname="col3" colwidth="18mm" /><colspec colnum="4" colname="col4" colwidth="18mm" /><colspec colnum="5" colname="col5" colwidth="18mm" /><colspec colnum="6" colname="col6" colwidth="18mm" /><colspec colnum="7" colname="col7" colwidth="18mm" /><colspec colnum="8" colname="col8" colwidth="18mm" /><colspec colnum="9" colname="col9" colwidth="18mm" /><thead valign="top"><row><entry colsep="0">Time</entry><entry colsep="0">Lot 1</entry><entry colsep="0">Lot 2</entry><entry colsep="0">Lot 3</entry><entry colsep="0">Lot 4</entry><entry colsep="0">Lot 5</entry><entry colsep="0">Lot 6</entry><entry colsep="0">Lot 7</entry><entry>Lot 8</entry></row></thead><tbody><row><entry align="center">0,25</entry><entry align="center">2,22</entry><entry align="center">0,62</entry><entry align="center">0,42</entry><entry align="center">0,86</entry><entry align="center">0,56</entry><entry align="center">1,03</entry><entry align="center">0,69</entry><entry align="center">0,26</entry></row><row><entry align="center">1,0</entry><entry align="center">2,59</entry><entry align="center">1,14</entry><entry align="center">1,23</entry><entry align="center">1,48</entry><entry align="center">0,96</entry><entry align="center">2,15</entry><entry align="center">1,43</entry><entry align="center">0,97</entry></row><row><entry align="center">2,00</entry><entry align="center">3,07</entry><entry align="center">1,71</entry><entry align="center">2,09</entry><entry align="center">1,94</entry><entry align="center">1,36</entry><entry align="center">3,16</entry><entry align="center">2,17</entry><entry align="center">1,39</entry></row><row><entry align="center">3</entry><entry align="center">3,55</entry><entry align="center">2,31</entry><entry align="center">2,75</entry><entry align="center">2,29</entry><entry align="center">1,76</entry><entry align="center">4,08</entry><entry align="center">2,82</entry><entry align="center">1,80</entry></row><row><entry align="center">4,0</entry><entry align="center">4,23</entry><entry align="center">3,03</entry><entry align="center">3,53</entry><entry align="center">2,75</entry><entry align="center">2,18</entry><entry align="center">4,92</entry><entry align="center">3,50</entry><entry align="center">2,31</entry></row><row><entry align="center">6</entry><entry align="center">7,99</entry><entry align="center">7,68</entry><entry align="center">8,69</entry><entry align="center">5,33</entry><entry align="center">3,78</entry><entry align="center">7,52</entry><entry align="center">5,70</entry><entry align="center">8,10</entry></row><row><entry align="center">8,0</entry><entry align="center">37,44</entry><entry align="center">33,84</entry><entry align="center">33,84</entry><entry align="center">26,20</entry><entry align="center">17,00</entry><entry align="center">21,59</entry><entry align="center">21,02</entry><entry align="center">37,27</entry></row><row><entry align="center">10</entry><entry align="center">77,09</entry><entry align="center">69,85</entry><entry align="center">65,51</entry><entry align="center">61,77</entry><entry align="center">49,89</entry><entry align="center">50,98</entry><entry align="center">53,48</entry><entry align="center">67,64</entry></row><row><entry align="center">12</entry><entry align="center">91,26</entry><entry align="center">85,72</entry><entry align="center">84,25</entry><entry align="center">83,55</entry><entry align="center">77,65</entry><entry align="center">75,68</entry><entry align="center">78,00</entry><entry align="center">82,66</entry></row><row><entry align="center">16</entry><entry align="center">96,15</entry><entry align="center">90,48</entry><entry align="center">95,35</entry><entry align="center">97,34</entry><entry align="center">96,94</entry><entry align="center">95,19</entry><entry align="center">96,17</entry><entry align="center">90,35</entry></row></tbody></tgroup></table></tables>

0262In vitro release profiles obtained in 0.1N HCl for three batches of finished composition comprising IR (50% w/w sodium oxybate dose) and MR microparticles (50% w/w sodium oxybate dose), prepared as described in Example 1, are provided in Table 2f. The sodium oxybate dose per vessel was 4.5g, 6g and 7.5g respectively and dissolution was determined in 900 mL of 0.1N HCl dissolution medium using the USP apparatus 2. The dissolution medium was maintained at 37.0 ± 0.5°C and the rotating paddle speed was fixed at 100 rpm. Single dose units were poured in a container containing 50 mL of tap water. After 5 minutes, the suspension was poured in the dissolution vessel containing 840 mL of 0.1N HCl dissolution medium. 10 mL of water were used to rinse the container and were added to the dissolution vessel. <tables id="tabl0016" num="0016"><table frame="all"><title>Table 2f. Percent Sodium Oxybate Released in 0.1 N HCl Dissolution Medium for three batches of finished composition prepared according to Example 1</title><tgroup cols="4"><colspec colnum="1" colname="col1" colwidth="45mm" align="center" /><colspec colnum="2" colname="col2" colwidth="39mm" align="center" /><colspec colnum="3" colname="col3" colwidth="39mm" align="center" /><colspec colnum="4" colname="col4" colwidth="39mm" align="center" /><thead valign="top"><row><entry>Time (hour)</entry><entry>Batch 1</entry><entry>Batch 2</entry><entry>Batch 3</entry></row></thead><tbody><row><entry>0.5</entry><entry>50</entry><entry>49</entry><entry>50</entry></row><row><entry>1</entry><entry>50</entry><entry>50</entry><entry>50</entry></row><row><entry>3</entry><entry>50</entry><entry>50</entry><entry>50</entry></row><row><entry>6</entry><entry>52</entry><entry>52</entry><entry>53</entry></row><row><entry>8</entry><entry>61</entry><entry>64</entry><entry>63</entry></row><row><entry>12</entry><entry>90</entry><entry>93</entry><entry>97</entry></row><row><entry>16</entry><entry>96</entry><entry>94</entry><entry>95</entry></row></tbody></tgroup></table></tables>

0263<figref idref="f0004">Figure 7</figref> and Table 2g depict dissolution profiles determined using a USP apparatus 2 in a 900 mL in 0.1N HCl dissolution medium of four finished compositions, two prepared according to Example 1 and two prepared according to Example 1bis. The dissolution medium was maintained at 37.0 ± 0.5 °C and the rotating paddle speed was fixed at 100 rpm. It shows that the composition according to the invention releases from 10 to 65% of its sodium oxybate at 1 and 3 hours and releases greater than 60% at 10 hours. <tables id="tabl0017" num="0017"><table frame="all"><title>Table 2g. Percent Sodium Oxybate Released in 0.1 N HCl Dissolution Medium for four batches of finished compositions, two prepared according to Example 1 and two prepared according to Example 1bis</title><tgroup cols="5"><colspec colnum="1" colname="col1" colwidth="32mm" align="center" /><colspec colnum="2" colname="col2" colwidth="35mm" align="center" /><colspec colnum="3" colname="col3" colwidth="35mm" align="center" /><colspec colnum="4" colname="col4" colwidth="31mm" align="center" /><colspec colnum="5" colname="col5" colwidth="31mm" align="center" /><thead valign="top"><row><entry>Time (hour)</entry><entry>Example 1bis</entry><entry>Example 1bis</entry><entry>Example 1</entry><entry>Example 1</entry></row></thead><tbody><row><entry>0</entry><entry>0</entry><entry>0</entry><entry>0</entry><entry>0</entry></row><row><entry>0.25</entry><entry>Nd</entry><entry>Nd</entry><entry>52</entry><entry>50</entry></row><row><entry>0,5</entry><entry>51</entry><entry>50</entry><entry>Nd</entry><entry>Nd</entry></row><row><entry>1</entry><entry>51</entry><entry>50</entry><entry>54</entry><entry>51</entry></row><row><entry>3</entry><entry>51</entry><entry>50</entry><entry>54</entry><entry>52</entry></row><row><entry>6</entry><entry>55</entry><entry>52</entry><entry>55</entry><entry>53</entry></row><row><entry>8</entry><entry>72</entry><entry>61</entry><entry>60</entry><entry>57</entry></row><row><entry>10</entry><entry>Nd</entry><entry>Nd</entry><entry>73</entry><entry>70</entry></row><row><entry>12</entry><entry>86</entry><entry>90</entry><entry>85</entry><entry>83</entry></row><row><entry>16</entry><entry>88</entry><entry>96</entry><entry>96</entry><entry>94</entry></row><row><entry>20</entry><entry>Nd</entry><entry>Nd</entry><entry>99</entry><entry>98</entry></row></tbody></tgroup><tgroup cols="5" rowsep="0"><colspec colnum="1" colname="col1" colwidth="32mm" align="justify" /><colspec colnum="2" colname="col2" colwidth="35mm" /><colspec colnum="3" colname="col3" colwidth="35mm" /><colspec colnum="4" colname="col4" colwidth="31mm" /><colspec colnum="5" colname="col5" colwidth="31mm" /><tbody><row><entry namest="col1" nameend="col5">Nd: not determined</entry></row></tbody></tgroup></table></tables>

0264<figref idref="f0004">Figure 8</figref> and Table 2h depict dissolution profiles determined using a USP apparatus 2 in a 900 mL phosphate buffer pH 6.8 dissolution medium for four finished compositions prepared according to Example 1 or 1bis. The dissolution medium was maintained at 37.0 ± 0.5 °C and the rotating paddle speed was fixed at 100 rpm. It shows that the composition according to the invention releases more than 80% of its sodium oxybate at 3 hours. <tables id="tabl0018" num="0018"><table frame="all"><title>Table 2h. Percent Sodium Oxybate Released in phosphate buffer pH 6.8 Dissolution Medium for four batches of finished compositions, two prepared according to Example 1 and two prepared according to Example 1bis</title><tgroup cols="5"><colspec colnum="1" colname="col1" colwidth="32mm" align="center" /><colspec colnum="2" colname="col2" colwidth="35mm" align="center" /><colspec colnum="3" colname="col3" colwidth="35mm" align="center" /><colspec colnum="4" colname="col4" colwidth="31mm" align="center" /><colspec colnum="5" colname="col5" colwidth="31mm" align="center" /><thead valign="top"><row><entry>Time (hour)</entry><entry>Example 1bis</entry><entry>Example 1bis</entry><entry>Example 1</entry><entry>Example 1</entry></row></thead><tbody><row><entry>0</entry><entry>0</entry><entry>0</entry><entry>0</entry><entry>0</entry></row><row><entry>0,25</entry><entry>Nd</entry><entry>Nd</entry><entry>75</entry><entry>84</entry></row><row><entry>0,5</entry><entry>99</entry><entry>98</entry><entry>Nd</entry><entry>Nd</entry></row><row><entry>1</entry><entry>101</entry><entry>101</entry><entry>100</entry><entry>102</entry></row><row><entry>1,5</entry><entry>101</entry><entry>101</entry><entry>106</entry><entry>108</entry></row><row><entry>2</entry><entry>100</entry><entry>100</entry><entry>Nd</entry><entry>Nd</entry></row><row><entry>3</entry><entry>103</entry><entry>100</entry><entry>Nd</entry><entry>Nd</entry></row><row><entry>4</entry><entry>103</entry><entry>100</entry><entry>Nd</entry><entry>Nd</entry></row><row><entry>6</entry><entry>102</entry><entry>99</entry><entry>101</entry><entry>102</entry></row><row><entry>8</entry><entry>103</entry><entry>99</entry><entry>101</entry><entry>105</entry></row><row><entry>10</entry><entry>103</entry><entry>99</entry><entry>101</entry><entry>Nd</entry></row><row><entry>12</entry><entry>101</entry><entry>99</entry><entry>101</entry><entry>102</entry></row><row><entry>16</entry><entry>Nd</entry><entry>Nd</entry><entry>100</entry><entry>101</entry></row><row><entry>20</entry><entry>Nd</entry><entry>Nd</entry><entry>99</entry><entry>98</entry></row></tbody></tgroup><tgroup cols="5" rowsep="0"><colspec colnum="1" colname="col1" colwidth="32mm" align="justify" /><colspec colnum="2" colname="col2" colwidth="35mm" /><colspec colnum="3" colname="col3" colwidth="35mm" /><colspec colnum="4" colname="col4" colwidth="31mm" /><colspec colnum="5" colname="col5" colwidth="31mm" /><tbody><row><entry namest="col1" nameend="col5">Nd: not determined</entry></row></tbody></tgroup></table></tables>

<u>Release Testing of MR Microparticles and Finished Compositions - effect of paddle speed:</u>

0265<figref idref="f0005">Figure 9</figref> and Table 2i depict dissolution profiles in 0.1N HCl of a batch of MR microparticles prepared according to Example 1. The dissolution profile of 4040 mg of microparticles corresponding to 2250 mg of sodium oxybate per vessel was determined using the USP apparatus 2. The dissolution medium temperature was maintained at 37.0 ± 0.5 °C, and the rotating paddle speed was set at 75 or 100 rpm. <tables id="tabl0019" num="0019"><table frame="all"><title>Table 2i. Percent Sodium Oxybate Released in 0.1N HCl Dissolution Medium for MR microparticles prepared according to Example 1</title><tgroup cols="3"><colspec colnum="1" colname="col1" colwidth="59mm" align="center" /><colspec colnum="2" colname="col2" colwidth="51mm" align="center" /><colspec colnum="3" colname="col3" colwidth="53mm" align="center" /><thead valign="top"><row><entry>Time (hour)</entry><entry>75rpm</entry><entry>100rpm</entry></row></thead><tbody><row><entry>0</entry><entry>0</entry><entry>0</entry></row><row><entry>0,25</entry><entry>1</entry><entry>1</entry></row><row><entry>1</entry><entry>2</entry><entry>1</entry></row><row><entry>2</entry><entry>2</entry><entry>2</entry></row><row><entry>3</entry><entry>3</entry><entry>2</entry></row><row><entry>4</entry><entry>3</entry><entry>3</entry></row><row><entry>6</entry><entry>6</entry><entry>5</entry></row><row><entry>8</entry><entry>28</entry><entry>26</entry></row><row><entry>10</entry><entry>65</entry><entry>62</entry></row><row><entry>12</entry><entry>86</entry><entry>84</entry></row><row><entry>16</entry><entry>97</entry><entry>97</entry></row></tbody></tgroup></table></tables>

0266<figref idref="f0005">Figure 10</figref> and Table 2j depict dissolution profiles in 0.1N HCl of a finished composition prepared according to Example 1. The dose per vessel was 4.5g and dissolution was determined in 900 mL of dissolution medium using the USP apparatus 2. The dissolution medium temperature was maintained at 37.0 ± 0.5°C and the rotating paddle speed was set at 75 or 100 rpm.

0267Single dose units were poured in a container containing 50 mL of tap water. After 5 minutes, the suspension was poured in the dissolution vessel containing 840 mL of 0.1N HCl medium. 10 mL of water were used to rinse the container and were added to the dissolution vessel. <tables id="tabl0020" num="0020"><table frame="all"><title>Table 2j. Percent Sodium Oxybate Released in 0.1N HCl Dissolution Medium for finished composition prepared according to Example 1</title><tgroup cols="3"><colspec colnum="1" colname="col1" colwidth="59mm" align="center" /><colspec colnum="2" colname="col2" colwidth="51mm" align="center" /><colspec colnum="3" colname="col3" colwidth="53mm" align="center" /><thead valign="top"><row><entry>Time (hour)</entry><entry>75rpm</entry><entry>100rpm</entry></row></thead><tbody><row><entry>0</entry><entry>0</entry><entry>0</entry></row><row><entry>0,25</entry><entry>48</entry><entry>47</entry></row><row><entry>1</entry><entry>53</entry><entry>52</entry></row><row><entry>3</entry><entry>54</entry><entry>53</entry></row><row><entry>6</entry><entry>56</entry><entry>56</entry></row><row><entry>8</entry><entry>65</entry><entry>65</entry></row><row><entry>10</entry><entry>82</entry><entry>79</entry></row><row><entry>12</entry><entry>92</entry><entry>89</entry></row><row><entry>16</entry><entry>97</entry><entry>96</entry></row><row><entry>20</entry><entry>98</entry><entry>98</entry></row></tbody></tgroup></table></tables>

EXAMPLE 3. IN VIVO PHARMACOKINETIC STUDY OF FINISHED COMPOSITION ACCORDING TO EXAMPLE 1BIS

0268Pharmacokinetic testing was undertaken in vivo in healthy human volunteers according to the principles described in <nplcit id="ncit0006" npl-type="s"><text>FDA's March 2003 Guidance for Industry on BIOAVAILABILITY AND BIOEQUIVALENCE STUDIES FOR ORALLY ADMINISTERED DRUG PRODUCTS - GENERAL CONSIDERATIONS</text></nplcit>. All testing was performed in subjects two hours after eating a standardized dinner. Xyrem^® doses were administered in two equipotent doses four hours apart. All other tested doses were manufactured as described in Example 1bis. The standardized dinner consisted of 25.5% fat, 19.6% protein, and 54.9% carbohydrates.

0269The finished composition of Example 1bis given as a 4.5 g once-nightly dose rather than a standard Xyrem^® dosing twice (2 x 2.25 g) nightly 4 hours apart, produced a dramatically different pharmacokinetic profile than Xyrem^® as shown in <figref idref="f0006">Figure 11</figref>. As summarized below (Tables 3a and 3b), 4.5 g nighttime doses of finished composition of the invention equivalent to twice-nightly doses of Xyrem^® (2 x 2.25 g) provided somewhat less total exposure to sodium oxybate with a later median T_max than the initial Xyrem^® dose. The relative bioavailability was about 88%. Composition according to the invention avoids the high second-dose peak concentration of Xyrem^® and therefore does not exhibit the substantial between-dose fluctuations in concentration, while achieving a comparable mean C_8h. <tables id="tabl0021" num="0021"><table frame="all"><title>Table 3a. Pharmacokinetic Parameters of finished composition of Example 1bis vs. Xyrem^®</title><tgroup cols="4"><colspec colnum="1" colname="col1" colwidth="65mm" align="center" /><colspec colnum="2" colname="col2" colwidth="35mm" align="center" /><colspec colnum="3" colname="col3" colwidth="23mm" align="center" /><colspec colnum="4" colname="col4" colwidth="41mm" align="center" /><thead valign="top"><row><entry /><entry>Mean Cmax (µg/mL) (% CV)</entry><entry>Mean AUCinf (h*µg/mL)</entry><entry>Median Tmax (hour) (min-max)</entry></row></thead><tbody><row><entry>Finished composition of Example 1bis 4.5 g</entry><entry>44.35 (38)</entry><entry>188.88 (44)</entry><entry>1.5 (0.5-4)</entry></row><row rowsep="0"><entry>Xyrem^® 2 x 2.25 g</entry><entry>1st dose: 33.41 (41)</entry><entry>214.32 (48)</entry><entry>1st dose: 1.00 (0.5-2)</entry></row><row><entry /><entry>2nd dose: 65.91 (40)</entry><entry /><entry>2nd dose: 4.50 (4.33-6.5)</entry></row></tbody></tgroup></table></tables><tables id="tabl0022" num="0022"><table frame="all"><title>Table 3b. Mean plasma concentration of gamma-hydroxybutyrate (microgram/mL) versus time of finished composition of Example 1bis and Xyrem^®</title><tgroup cols="5"><colspec colnum="1" colname="col1" colwidth="18mm" align="center" /><colspec colnum="2" colname="col2" colwidth="41mm" align="center" /><colspec colnum="3" colname="col3" colwidth="41mm" align="center" /><colspec colnum="4" colname="col4" colwidth="36mm" align="center" /><colspec colnum="5" colname="col5" colwidth="27mm" align="center" /><thead valign="top"><row><entry>Time (hour)</entry><entry>Finished composition Example 1bis 4.5g (2 h after meal) pooled mean (N=26)</entry><entry>Finished composition Example 1bis 6.0g (2 h after meal) pooled mean (N=19)</entry><entry>Finished composition Example 1bis 7.5g (2 h after meal) (N=11)</entry><entry>Xyrem^® (2x2.25g) part I (N=15)</entry></row></thead><tbody><row><entry>0</entry><entry>0.00</entry><entry>0.00</entry><entry>0.00</entry><entry>0.00</entry></row><row><entry>0.5</entry><entry>29.31</entry><entry>36.44</entry><entry>43.19</entry><entry>27.44</entry></row><row><entry>1</entry><entry>34.93</entry><entry>49.97</entry><entry>63.32</entry><entry>28.97</entry></row><row><entry>1.5</entry><entry>36.63</entry><entry>54.66</entry><entry>73.40</entry><entry>26.12</entry></row><row><entry>2</entry><entry>36.78</entry><entry>54.82</entry><entry>67.96</entry><entry>21.11</entry></row><row><entry>2.5</entry><entry>33.35</entry><entry>53.05</entry><entry>66.59</entry><entry>NA</entry></row><row><entry>3</entry><entry>30.28</entry><entry>50.25</entry><entry>62.13</entry><entry>13.93</entry></row><row><entry>3.5</entry><entry>27.30</entry><entry>47.22</entry><entry>59.45</entry><entry>10.25</entry></row><row><entry>4</entry><entry>23.66</entry><entry>43.06</entry><entry>57.40</entry><entry>6.92</entry></row><row><entry>4.5</entry><entry>19.89</entry><entry>39.13</entry><entry>50.85</entry><entry>57.33</entry></row><row><entry>5</entry><entry>16.55</entry><entry>34.28</entry><entry>45.09</entry><entry>52.27</entry></row><row><entry>5.5</entry><entry>13.62</entry><entry>32.11</entry><entry>44.94</entry><entry>43.55</entry></row><row><entry>6</entry><entry>12.40</entry><entry>25.84</entry><entry>42.36</entry><entry>35.20</entry></row><row><entry>6.5</entry><entry>11.25</entry><entry>22.36</entry><entry>41.02</entry><entry>27.44</entry></row><row><entry>7</entry><entry>11.27</entry><entry>18.07</entry><entry>40.76</entry><entry>19.36</entry></row><row><entry>7.5</entry><entry>9.65</entry><entry>15.41</entry><entry>35.83</entry><entry>13.88</entry></row><row><entry>8</entry><entry>6.86</entry><entry>12.80</entry><entry>30.94</entry><entry>9.24</entry></row><row><entry>10</entry><entry>1.08</entry><entry>2.38</entry><entry>7.99</entry><entry>2.64</entry></row><row><entry>12</entry><entry>NC</entry><entry>0.52</entry><entry>1.47</entry><entry>NC</entry></row></tbody></tgroup><tgroup cols="5" rowsep="0"><colspec colnum="1" colname="col1" colwidth="18mm" align="justify" /><colspec colnum="2" colname="col2" colwidth="41mm" /><colspec colnum="3" colname="col3" colwidth="41mm" /><colspec colnum="4" colname="col4" colwidth="36mm" /><colspec colnum="5" colname="col5" colwidth="27mm" /><tbody><row><entry namest="col1" nameend="col5">NC: Not Calculated</entry></row></tbody></tgroup></table></tables>

0270The pharmacokinetic profile of a single 6 g dose of finished composition produced according to Example 1bis was also tested and found to have a similar pharmacokinetic profile as the 4.5 g dose. <figref idref="f0006">Figure 12</figref> provides a pharmacokinetic profile comparison of a single 4.5 g or 6 g dose of finished composition according to Example 1bis in the same 7 subjects. The pharmacokinetic profile for a 7.5 g dose of finished formulation produced according to Example 1bis was also obtained. <figref idref="f0007">Figure 13</figref> and Table 3c provide data on a single 4.5 g, 6 g and 7.5 g dose, showing effects on T_max, C_max, C_8h, AUC_8h and AUC_inf related to dose strength. The 7.5g dose achieved a mean C_8h equal to about 31 microgram/mL which represents approximately 128.5% of the C_8h obtained for Xyrem^® dosed 2 x 3.75g which was extrapolated to be approximately 24.07 microgram/mL from published data. The 7.5 g dose achieved a ratio of AUC_8h to AUC_inf of about 0.89, whereas the ratio was 0.83 and 0.93 for the 4.5g and 6g doses respectively. <tables id="tabl0023" num="0023"><table frame="all"><title>Table 3c. Pharmacokinetic Parameters of 4.5g, 6g, and 7.5g of finished composition produced according to Example 1bis</title><tgroup cols="6"><colspec colnum="1" colname="col1" colwidth="32mm" align="center" /><colspec colnum="2" colname="col2" colwidth="25mm" align="center" /><colspec colnum="3" colname="col3" colwidth="27mm" align="center" /><colspec colnum="4" colname="col4" colwidth="27mm" align="center" /><colspec colnum="5" colname="col5" colwidth="25mm" align="center" /><colspec colnum="6" colname="col6" colwidth="25mm" align="center" /><thead valign="top"><row><entry>Finished composition according to Example 1bis</entry><entry>Mean C_max (µg/mL) (% CV)</entry><entry>Mean AUC_inf (h*µg/mL) (% CV)</entry><entry>Mean AUC_8h (h*µg/mL) (% CV)</entry><entry>Median T_max (h) (min-max)</entry><entry>Mean C_8h (µg/mL) (% CV)</entry></row></thead><tbody><row><entry>4.5 g</entry><entry>44.35 (38)</entry><entry>188.88 (47)</entry><entry>174.68 (48)</entry><entry>1.5 (0.5-4)</entry><entry>6.86 (84)</entry></row><row><entry>6 g</entry><entry>65.46 (35)</entry><entry>307.34 (48)</entry><entry>290.97 (47)</entry><entry>3 (0.5-5.5)</entry><entry>12.8 (82)</entry></row><row><entry>7.5 g</entry><entry>88.21 (30)</entry><entry>454.99(34)</entry><entry>404.88 (31)</entry><entry>2 (0.5-6)</entry><entry>30.94 (34)</entry></row></tbody></tgroup></table></tables>

0271<figref idref="f0007">Figure 14</figref> and table 3d compare the pharmacokinetic parameters AUC_inf and C_8h obtained for 7.5 g of a finished composition according to Example 1bis to the same parameters calculated for 2 x 4.5 g, i.e. 9 g total dose of Xyrem^®. The data show that a 7.5g dose of a formulation according to the invention given once nightly exhibits a similar PK profile to 9g of Xyrem^® given in two separate equal doses. <tables id="tabl0024" num="0024"><table frame="all"><title>Table 3d. Pharmacokinetic Parameters of 7.5g of finished composition produced according to Example 1bis compared to 2 x 4.5g of Xyrem^®</title><tgroup cols="5"><colspec colnum="1" colname="col1" colwidth="72mm" align="center" /><colspec colnum="2" colname="col2" colwidth="18mm" align="center" /><colspec colnum="3" colname="col3" colwidth="21mm" align="center" /><colspec colnum="4" colname="col4" colwidth="26mm" align="center" /><colspec colnum="5" colname="col5" colwidth="25mm" align="center" /><thead><row><entry valign="middle" /><entry valign="top">Mean C_8h (µg/mL)</entry><entry valign="top">Mean AUC_int (µg/mL*h)</entry><entry valign="middle">Ratio (%) AUC_inf composition to AUC_inf Xyrem^®</entry><entry valign="middle">Ratio (%) C_8h composition to C_8h Xyrem^®</entry></row></thead><tbody><row><entry>Xyrem^® 2 x 4.5 g</entry><entry valign="middle">28.9</entry><entry valign="middle">518</entry><entry valign="middle">NA</entry><entry valign="middle">NA</entry></row><row rowsep="0" valign="middle"><entry>Finished composition according to Example 1bis</entry><entry morerows="1" rowsep="1">30.9</entry><entry morerows="1" rowsep="1">455</entry><entry morerows="1" rowsep="1">88%</entry><entry morerows="1" rowsep="1">107%</entry></row><row valign="middle"><entry>7.5 g</entry></row></tbody></tgroup></table></tables>

EXAMPLE 4. ALTERNATIVE FORMULATION

0272Tables 4a-4d provide the qualitative and quantitative compositions of IR microparticles, MR microparticles, and mixtures of IR and MR microparticles. The physical structure of the microparticles showing the qualitative and quantitative composition of the IR and MR microparticles is depicted in <figref idref="f0008">Figure 15</figref>.

0273Briefly, sodium oxybate immediate release (IR) microparticle were prepared as follows: 1615.0g of Sodium Oxybate and 85.0g of polyvinylpyrrolidone (Povidone K30-Plasdone^™ K29/32 from ISP) were solubilized in 1894.3g of absolute ethyl alcohol and 1262.9g of water. The solution was entirely sprayed onto 300g of microcrystalline cellulose spheres (Cellets^™ 127) in a fluid bed spray coater apparatus. IR microparticles with volume mean diameter of about 270 microns were obtained.

0274Sodium oxybate modified release (MR) microparticles were prepared as follows: 4.0g of Methacrylic acid copolymer Type C (Eudragit^™ L100-55), 49.3g of Methacrylic acid copolymer Type B (Eudragit^™ S100), 80g of Hydrogenated cottonseed oil (Lubritab^™), were dissolved in 1200.0g of isopropanol at 78°C. The solution was sprayed entirely on 400.0g of IR microparticles prepared above in a fluid bed spray coater apparatus with an inlet temperature 48°C, spraying rate around 11g per min and atomization pressure 1.3 bar. MR microparticles were dried for two hours with inlet temperature set to 56°C. MR microparticles with volume mean diameter of about 330 microns were obtained.

0275The finished composition, which contained a 50:50 mixture of MR and IR microparticles calculated on their sodium oxybate content, was prepared as follows: 27.86g of IR microparticles, 37.15g of MR microparticles, 1.13g of malic acid (D/L malic acid), 0.50g of xanthan gum (Xantural^™ 75 from Kelco), 0.75g of carrageenan gum (Viscarin^™ PH209 from FMC Biopolymer), 0.75g of hydroxyethylcellulose (Natrosol^™ 250M from Ashland) and 0.34g of magnesium stearate were mixed. Individual samples of 6.85g (corresponding to a 4.5g sodium oxybate dose with half of the dose as immediate-release fraction and half of the dose as modified release fraction) were weighed. <tables id="tabl0025" num="0025"><table frame="all"><title>Table 4a: Composition of IR Microparticles</title><tgroup cols="3"><colspec colnum="1" colname="col1" colwidth="54mm" /><colspec colnum="2" colname="col2" colwidth="62mm" /><colspec colnum="3" colname="col3" colwidth="47mm" /><thead valign="top"><row><entry align="center">Component</entry><entry align="center">Function</entry><entry align="center"><b>Quantity</b> per 2.25 g dose (g)</entry></row></thead><tbody><row><entry>Sodium oxybate</entry><entry>Drug substance</entry><entry>2.25</entry></row><row><entry>Microcrystalline cellulose spheres</entry><entry>Core</entry><entry>0.418</entry></row><row><entry>Povidone K30</entry><entry>Binder and excipient in diffusion coating</entry><entry>0.118</entry></row><row><entry>Ethyl alcohol</entry><entry>Solvent</entry><entry>Eliminated during processing</entry></row><row><entry>Purified water</entry><entry>Solvent</entry><entry>Eliminated during processing</entry></row><row><entry>Total</entry><entry /><entry>2.786</entry></row></tbody></tgroup></table></tables><tables id="tabl0026" num="0026"><table frame="all"><title>Table 4b: Composition of MR Microparticles</title><tgroup cols="3"><colspec colnum="1" colname="col1" colwidth="57mm" /><colspec colnum="2" colname="col2" colwidth="43mm" /><colspec colnum="3" colname="col3" colwidth="47mm" /><thead valign="top"><row><entry align="center">Component</entry><entry align="center">Function</entry><entry align="center">Quantity per 2.25 g dose (g)</entry></row></thead><tbody><row><entry>IR Microparticles</entry><entry>Core of MR Microparticles</entry><entry>2.786</entry></row><row><entry>Hydrogenated Vegetable Oil</entry><entry>Coating excipient</entry><entry>0.557</entry></row><row><entry>Methacrylic acid Copolymer Type C</entry><entry>Coating excipient</entry><entry>0.028</entry></row><row><entry>Methacrylic acid Copolymer Type B</entry><entry>Coating excipient</entry><entry>0.344</entry></row><row><entry>Isopropyl alcohol</entry><entry>Solvent</entry><entry>Eliminated during processing</entry></row><row><entry>Total</entry><entry /><entry>3.715</entry></row></tbody></tgroup></table></tables><tables id="tabl0027" num="0027"><table frame="all"><title>Table 4c: Qualitative Finished Composition</title><tgroup cols="3"><colspec colnum="1" colname="col1" colwidth="37mm" /><colspec colnum="2" colname="col2" colwidth="70mm" /><colspec colnum="3" colname="col3" colwidth="44mm" align="center" /><thead valign="middle"><row><entry align="center">Component</entry><entry align="center">Function</entry><entry>Quantity per 4.5 g dose (g)</entry></row></thead><tbody><row valign="middle"><entry>MR microparticles</entry><entry>Modified release fraction of sodium oxybate</entry><entry>3.715</entry></row><row><entry valign="middle">IR microparticles</entry><entry>Immediate release fraction of sodium oxybate</entry><entry valign="middle">2.786</entry></row><row valign="middle"><entry>Malic acid</entry><entry>Acidifying agent</entry><entry>0.113</entry></row><row valign="middle"><entry>Xanthan gum</entry><entry>Suspending agent</entry><entry>0.050</entry></row><row valign="middle"><entry>Hydroxyethylcellulose</entry><entry>Suspending agent</entry><entry>0.075</entry></row><row valign="middle"><entry>Carrageenan gum</entry><entry>Suspending agent</entry><entry>0.075</entry></row><row valign="middle"><entry>Magnesium stearate</entry><entry>Lubricant</entry><entry>0.034</entry></row><row valign="middle"><entry>Total</entry><entry /><entry>6.848</entry></row></tbody></tgroup></table></tables><tables id="tabl0028" num="0028"><table frame="all"><title>Table 4d: Quantitative finished composition</title><tgroup cols="3"><colspec colnum="1" colname="col1" colwidth="57mm" /><colspec colnum="2" colname="col2" colwidth="32mm" /><colspec colnum="3" colname="col3" colwidth="44mm" /><thead valign="top"><row><entry align="center">Component</entry><entry align="center">Function</entry><entry align="center">Quantity per 4.5 g dose (g)</entry></row></thead><tbody><row><entry>Sodium oxybate</entry><entry>Drug substance</entry><entry>4.5</entry></row><row><entry>Microcrystalline cellulose spheres</entry><entry>Core</entry><entry>0.836</entry></row><row><entry>Povidone K30</entry><entry>Binder</entry><entry>0.237</entry></row><row><entry>Hydrogenated Vegetable Oil</entry><entry>Coating excipient</entry><entry>0.557</entry></row><row><entry>Methacrylic acid Copolymer Type C</entry><entry>Coating excipient</entry><entry>0.028</entry></row><row><entry>Methacrylic acid Copolymer Type B</entry><entry>Coating excipient</entry><entry>0.344</entry></row><row><entry>Malic acid</entry><entry>Acidifying agent</entry><entry>0.113</entry></row><row><entry>Xanthan gum</entry><entry>Suspending agent</entry><entry>0.050</entry></row><row><entry>Hydroxyethylcellulose</entry><entry>Suspending agent</entry><entry>0.075</entry></row><row><entry>Carrageenan gum</entry><entry>Suspending agent</entry><entry>0.075</entry></row><row><entry>Magnesium stearate</entry><entry>Lubricant</entry><entry>0.034</entry></row><row><entry>Total</entry><entry /><entry>6.848</entry></row></tbody></tgroup></table></tables>

EXAMPLE 4BIS:

0276An alternative formulation to example 4 is described in example 4bis. Sodium oxybate immediate release (IR) microparticles were prepared by coating the IR microparticles described in example 4 with a top coat layer. IR Microparticles were prepared as follows: 170.0 of hydroxypropyl cellulose (Klucel^™ EF Pharm from Hercules) were solubilized in 4080.0g of acetone. The solution was entirely sprayed onto 1530.0g of the IR microparticles of Example 4 in a fluid bed spray coater apparatus. IR Microparticles with volume mean diameter of about 298 microns were obtained (see Table 4bis-a).

0277Sodium oxybate modified release (MR) microparticles were prepared as described in example 4 (see Table 4b).

0278The finished composition, which contains a 50:50 mixture of MR and IR microparticles calculated based on sodium oxybate content, was prepared as follows: 424.99g of the above IR microparticles, 509.98g of the above MR microparticles, 30.89g of malic acid (D/L malic acid), 4.93g of xanthan gum (Xantural^™ 75 from Kelco), 4.93g of colloidal silicon dioxide (Aerosil^™

0279200 from Degussa) and 9.86g of magnesium stearate were mixed. Individual samples of 7.18g (corresponding to a 4.5g dose of sodium oxybate with half of the dose as an immediate-release fraction and half of the dose as a modified release fraction) were weighed. (see Tables 4bis-b and 4bis-c). <tables id="tabl0029" num="0029"><table frame="all"><title>Table 4bis-a: Composition of IR Microparticles</title><tgroup cols="3"><colspec colnum="1" colname="col1" colwidth="54mm" /><colspec colnum="2" colname="col2" colwidth="62mm" /><colspec colnum="3" colname="col3" colwidth="47mm" /><thead valign="top"><row><entry align="center">Component</entry><entry align="center">Function</entry><entry align="center">Quantity per 2.25 g dose (g)</entry></row></thead><tbody><row><entry>Sodium oxybate</entry><entry>Drug substance</entry><entry>2.25</entry></row><row><entry>Microcrystalline cellulose spheres</entry><entry>Core</entry><entry>0.418</entry></row><row><entry>Povidone K30</entry><entry>Binder and excipient in diffusion coating</entry><entry>0.118</entry></row><row><entry>Hydroxypropyl cellulose</entry><entry>Top coat</entry><entry>0.310</entry></row><row><entry>Ethyl alcohol</entry><entry>Solvent</entry><entry>Eliminated during processing</entry></row><row><entry>Purified water</entry><entry>Solvent</entry><entry>Eliminated during processing</entry></row><row><entry>Acetone</entry><entry>Solvent</entry><entry>Eliminated during processing</entry></row><row><entry>Total</entry><entry /><entry>3.096</entry></row></tbody></tgroup></table></tables><tables id="tabl0030" num="0030"><table frame="all"><title>Table 4bis-b: Qualitative Finished Composition</title><tgroup cols="3"><colspec colnum="1" colname="col1" colwidth="39mm" /><colspec colnum="2" colname="col2" colwidth="70mm" /><colspec colnum="3" colname="col3" colwidth="45mm" /><thead valign="middle"><row><entry align="center">Component</entry><entry align="center">Function</entry><entry align="center">Quantity per 4.5 g dose (g)</entry></row></thead><tbody valign="middle"><row><entry>MR microparticles</entry><entry>Modified release fraction of sodium oxybate</entry><entry align="right">3.715</entry></row><row><entry>IR microparticles</entry><entry>Immediate release fraction of sodium oxybate</entry><entry align="right">3.096</entry></row><row><entry>Malic acid</entry><entry>Acidifying agent</entry><entry align="right">0.225</entry></row><row><entry>Xanthan gum</entry><entry>Suspending agent</entry><entry align="right">0.036</entry></row><row><entry>Colloidal silicon dioxide</entry><entry>Gliding agent</entry><entry align="right">0.036</entry></row><row><entry>Magnesium stearate</entry><entry>Lubricant</entry><entry align="right">0.072</entry></row><row><entry>Total</entry><entry /><entry align="right">7.180</entry></row></tbody></tgroup></table></tables><tables id="tabl0031" num="0031"><table frame="all"><title>Table 4bis-c: Quantitative finished composition</title><tgroup cols="3"><colspec colnum="1" colname="col1" colwidth="57mm" /><colspec colnum="2" colname="col2" colwidth="32mm" align="center" /><colspec colnum="3" colname="col3" colwidth="44mm" align="center" /><thead valign="middle"><row><entry align="center">Component</entry><entry>Function</entry><entry>Quantity per 4.5 g dose (g)</entry></row></thead><tbody valign="middle"><row><entry>Sodium oxybate</entry><entry>Drug substance</entry><entry>4.5</entry></row><row><entry>Microcrystalline cellulose spheres</entry><entry>Core</entry><entry>0.836</entry></row><row><entry>Povidone K30</entry><entry>Binder</entry><entry>0.237</entry></row><row><entry>Hydroxypropyl cellulose</entry><entry>Top coat</entry><entry>0.310</entry></row><row><entry>Hydrogenated Vegetable Oil</entry><entry>Coating excipient</entry><entry>0.557</entry></row><row><entry>Methacrylic acid Copolymer Type C</entry><entry>Coating excipient</entry><entry>0.028</entry></row><row><entry>Methacrylic acid Copolymer Type B</entry><entry>Coating excipient</entry><entry>0.344</entry></row><row><entry>Malic acid</entry><entry>Acidifying agent</entry><entry>0.225</entry></row><row><entry>Xanthan gum</entry><entry>Suspending agent</entry><entry>0.036</entry></row><row><entry>Colloidal silicon dioxide</entry><entry>Gliding agent</entry><entry>0.036</entry></row><row><entry>Magnesium stearate</entry><entry>Lubricant</entry><entry>0.072</entry></row><row><entry>Total</entry><entry /><entry>7.180</entry></row></tbody></tgroup></table></tables>

0280Compared to the finished composition described in example 4, this alternative composition has the following characteristics: same MR microparticles, same IR microparticles but with a top coat, increased amount of malic acid, only one suspending agent (xanthan gum) and presence ofa glidant.

EXAMPLE 5 IN VITRO RELEASE PROFILES OF IR, MR AND FINISHED COMPOSITIONS OF FORMULATION OF EXAMPLE 4 AND 4BIS

<i>Dissolution testing of MR Microparticles from Example 4 -protocol (2h 0.1N HCl</i> / <i>phosphate buffer pH 6.8)</i>

028149.1 g of MR microparticles from Example 4 were mixed with 0.5g of magnesium stearate (from Peter Greven) and 0.25g of colloidal silicon dioxide (Aerosil^™ 200 from Evonik).

0282The dissolution profile of 3770 mg of the mixture which correspond to 2250mg of sodium oxybate per vessel was determined using the USP apparatus 2. Dissolution medium temperature was maintained at 37.0 ± 0.5 °C, and the rotating paddle speed was set at 75 rpm.

0283After 2 hours in 750 mL of 0.1N HCl dissolution medium, 6.5 g of monobasic potassium phosphate was added in the dissolution vessel. pH and volume were then respectively adjusted to 6.8 and 950 mL. The potassium phosphate concentration was equal to 0.05 M in the dissolution medium after pH and volume adjustment. The release profile is shown in <figref idref="f0008">Figure 16</figref> and Table 5a. <tables id="tabl0032" num="0032"><table frame="all"><title>Table 5a. Percent Sodium Oxybate Released in two sequential dissolution media (0.1N HCl for two hours, then phosphate buffer pH 6.8) for MR microparticles of sodium oxybate prepared according to Example 4</title><tgroup cols="2"><colspec colnum="1" colname="col1" colwidth="68mm" align="center" /><colspec colnum="2" colname="col2" colwidth="96mm" align="center" /><thead><row><entry>Time (h)</entry><entry>% sodium oxybate dissolved</entry></row></thead><tbody valign="bottom"><row><entry>0</entry><entry>0</entry></row><row><entry>1</entry><entry>1</entry></row><row><entry>2</entry><entry>2</entry></row><row><entry>2,25</entry><entry>9</entry></row><row><entry>2,5</entry><entry>40</entry></row><row><entry>3</entry><entry>89</entry></row><row><entry>4</entry><entry>102</entry></row><row><entry>6</entry><entry>103</entry></row></tbody></tgroup></table></tables>

0284The sodium oxybate was not released in the 0.1N HCl medium during two hours. After the switch at pH 6.8, 40% of the API was released after 30 minutes and 90% of API after 1 hour. <figref idref="f0009">Figure 17</figref> overlays the dissolution profile of the MR microparticles of Example 4 with the dissolution profile for MR microparticles reported in Supernus <patcit id="pcit0018" dnum="US8193211B"><text>USP 8,193,211</text></patcit>, <figref idref="f0002">figure 3</figref>. It shows that the dissolution profiles are different and especially that the MR microparticles according to the invention release greater than 80% of its sodium oxybate at 3 hours, whereas the MR microparticles described in Supernus <patcit id="pcit0019" dnum="US8193211B"><text>USP 8,193,211</text></patcit>, <figref idref="f0002">figure 3</figref> do not and exhibit a much slower releasing profile.

<u>Dissolution testing of finished composition according to Example 4 in deionized water:</u>

0285The dissolution profile of the quantity equivalent to 4.5g of sodium oxybate of the finished composition of the Example 4 was determined in 900 mL of deionized water using the USP apparatus 2. The dissolution medium was maintained at 37.0 ± 0.5°C and the rotating paddle speed was set at 50 rpm. The release profile of is shown in <figref idref="f0009">Figure 18</figref> and Table 5b. <tables id="tabl0033" num="0033"><table frame="all"><title>Table 5b. Percent Sodium Oxybate Released in deionized water for finished composition of sodium oxybate prepared according to Example 4</title><tgroup cols="2"><colspec colnum="1" colname="col1" colwidth="83mm" align="center" /><colspec colnum="2" colname="col2" colwidth="81mm" align="center" /><thead valign="middle"><row><entry>Time (hour)</entry><entry>Example 4</entry></row></thead><tbody valign="middle"><row><entry>0</entry><entry>0</entry></row><row><entry>0,25</entry><entry>52</entry></row><row><entry>1</entry><entry>55</entry></row><row><entry>2</entry><entry>53</entry></row><row><entry>3</entry><entry>54</entry></row><row><entry>4</entry><entry>52</entry></row><row><entry>5</entry><entry>54</entry></row><row><entry>6</entry><entry>60</entry></row><row><entry>7</entry><entry>78</entry></row><row><entry>8</entry><entry>90</entry></row></tbody></tgroup></table></tables>

0286The IR fraction of sodium oxybate was solubilized in 15 minutes. The release of sodium oxybate from the modified release fraction started after 5 hours with 90% of the total dose released at 8 hours.

0287An overlay of the release profile of the finished composition of the Example 4 versus that reported in <patcit id="pcit0020" dnum="US20120076865A"><text>USP 2012/0076865</text></patcit><figref idref="f0001">Figure 2</figref> is shown in <figref idref="f0010">Figure 19</figref>. It shows that the dissolution profiles are different. The formulation described in <patcit id="pcit0021" dnum="US20120076865A"><text>USP 2012/0076865</text></patcit><figref idref="f0001">figure 2</figref> does not exhibit a lag phase after the dissolution of the immediate release part.

0288<figref idref="f0010">Figure 20</figref> and Table 5c depict dissolution profiles determined using a USP apparatus 2 in a 900 mL in 0.1N HCl dissolution medium of three finished compositions prepared according to Example 4bis. The dissolution medium was maintained at 37.0 ± 0.5 °C and the rotating paddle speed was fixed at 100 rpm. It shows that the composition according to the invention releases from 10 to 65% of its sodium oxybate at 1 and 3 hours and releases greater than 60% at 10 hours. <tables id="tabl0034" num="0034"><table frame="all"><title>Table 5c. Percent Sodium Oxybate Released in 0.1 N HCl Dissolution Medium for three batches of finished composition prepared according to Example 4bis</title><tgroup cols="4"><colspec colnum="1" colname="col1" colwidth="46mm" /><colspec colnum="2" colname="col2" colwidth="39mm" align="center" /><colspec colnum="3" colname="col3" colwidth="39mm" align="center" /><colspec colnum="4" colname="col4" colwidth="39mm" align="center" /><thead valign="middle"><row><entry>Time (Hour)</entry><entry>Batch 1</entry><entry>Batch 2</entry><entry>Batch 3</entry></row></thead><tbody valign="middle"><row><entry align="center">0</entry><entry>0</entry><entry>0</entry><entry>0</entry></row><row><entry align="center">0,25</entry><entry>50</entry><entry>Nd</entry><entry>Nd</entry></row><row><entry align="center">0,5</entry><entry>51</entry><entry>50</entry><entry>49</entry></row><row><entry align="center">0,75</entry><entry>51</entry><entry>Nd</entry><entry>Nd</entry></row><row><entry align="center">1</entry><entry>51</entry><entry>51</entry><entry>51</entry></row><row><entry align="center">1,5</entry><entry>51</entry><entry>Nd</entry><entry>Nd</entry></row><row><entry align="center">2</entry><entry>51</entry><entry>Nd</entry><entry>Nd</entry></row><row><entry align="center">3</entry><entry>51</entry><entry>52</entry><entry>53</entry></row><row><entry align="center">4</entry><entry>51</entry><entry>Nd</entry><entry>Nd</entry></row><row><entry align="center">6</entry><entry>55</entry><entry>57</entry><entry>57</entry></row><row><entry align="center">8</entry><entry>74</entry><entry>70</entry><entry>71</entry></row><row><entry align="center">10</entry><entry>89</entry><entry>Nd</entry><entry>Nd</entry></row><row><entry align="center">12</entry><entry>93</entry><entry>90</entry><entry>92</entry></row><row><entry align="center">16</entry><entry>94</entry><entry>95</entry><entry>97</entry></row></tbody></tgroup><tgroup cols="4" rowsep="0"><colspec colnum="1" colname="col1" colwidth="46mm" align="justify" /><colspec colnum="2" colname="col2" colwidth="39mm" /><colspec colnum="3" colname="col3" colwidth="39mm" /><colspec colnum="4" colname="col4" colwidth="39mm" /><tbody><row><entry namest="col1" nameend="col4">Nd = not determined</entry></row></tbody></tgroup></table></tables>

0289<figref idref="f0011">Figure 21</figref> and Table 5d depict dissolution profile determined using a USP apparatus 2 in a 900 mL phosphate buffer pH 6.8 dissolution medium for a finished composition prepared according to Example 4bis. The dissolution medium was maintained at 37.0 ± 0.5 °C and the rotating paddle speed was set at 100 rpm. It shows that the composition according to the invention releases more than 80% of its sodium oxybate at 3 hours. <tables id="tabl0035" num="0035"><table frame="all"><title>Table 5d. Percent Sodium Oxybate Released in phosphate buffer pH 6.8 Dissolution Medium for finished composition prepared according to Example 4bis</title><tgroup cols="2"><colspec colnum="1" colname="col1" colwidth="81mm" align="center" /><colspec colnum="2" colname="col2" colwidth="83mm" align="center" /><thead valign="middle"><row><entry>Time (Hour)</entry><entry>Example 4bis</entry></row></thead><tbody valign="middle"><row><entry>0</entry><entry>0</entry></row><row><entry>0,25</entry><entry>54</entry></row><row><entry>0,5</entry><entry>54</entry></row><row><entry>0,75</entry><entry>55</entry></row><row><entry>1,0</entry><entry>56</entry></row><row><entry>1,5</entry><entry>63</entry></row><row><entry>2</entry><entry>77</entry></row><row><entry>3</entry><entry>103</entry></row><row><entry>4</entry><entry>105</entry></row><row><entry>6</entry><entry>105</entry></row><row><entry>8</entry><entry>102</entry></row><row><entry>10</entry><entry>101</entry></row><row><entry>12</entry><entry>104</entry></row><row><entry>16</entry><entry>100</entry></row></tbody></tgroup></table></tables>

EXAMPLE 6. IN VIVO PHARMACOKINETIC STUDY OF FINISHED COMPOSITION ACCORDING TO EXAMPLE 4BIS

0290Pharmacokinetic testing was undertaken in vivo in healthy human volunteers according to the principles described in <nplcit id="ncit0007" npl-type="s"><text>FDA's March 2003 Guidance for Industry on BIOAVAILABILITY AND BIOEQUIVALENCE STUDIES FOR ORALLY ADMINISTERED DRUG PRODUCTS - GENERAL CONSIDERATIONS</text></nplcit>. All testing was performed in subjects two hours after eating a standardized dinner. Xyrem^® doses were administered in two equipotent doses four hours apart. All other tested doses were manufactured as described in Example 4bis. The standardized dinner consisted of 25.5% fat, 19.6% protein, and 54.9% carbohydrates.

0291The finished composition of Example 4bis given as a 4.5 g once-nightly dose rather than a standard Xyrem^® dosing twice (2 x 2.25 g) nightly 4 hours apart, produced a dramatically different pharmacokinetic profile than Xyrem^® as shown in <figref idref="f0011">Figure 22</figref>. As summarized below (Tables 6a and 6b), 4.5 g nighttime doses of finished composition of the invention equivalent to twice-nightly doses of Xyrem^® (2 x 2.25 g) provided somewhat less total exposure to sodium oxybate with a later median T_max than the initial Xyrem^® dose. The relative bioavailability was about 88%. Composition according to the invention avoids the high second-dose peak concentration of Xyrem^® and therefore does not exhibit the substantial between-dose fluctuations in concentration, while achieving a comparable mean C_8h. <tables id="tabl0036" num="0036"><table frame="all"><title>Table 6a. Pharmacokinetic Parameters of finished composition of Example 4bis vs. Xyrem^®</title><tgroup cols="6"><colspec colnum="1" colname="col1" colwidth="36mm" /><colspec colnum="2" colname="col2" colwidth="24mm" /><colspec colnum="3" colname="col3" colwidth="27mm" /><colspec colnum="4" colname="col4" colwidth="27mm" /><colspec colnum="5" colname="col5" colwidth="26mm" /><colspec colnum="6" colname="col6" colwidth="22mm" /><thead valign="top"><row><entry align="center" /><entry align="center">Mean C_max (µg/mL) (% CV)</entry><entry align="center">Mean AUC_inf (h*µg/mL) (% CV)</entry><entry align="center">Mean AUC_8h (h*µg/mL) (% CV)</entry><entry align="center">Median T_max (hour) (min-max)</entry><entry align="center">Mean C_8h (µg/mL) (% CV)</entry></row></thead><tbody valign="middle"><row><entry align="center">Finished composition of Example 4bis 4.5g</entry><entry>43.47 (49)</entry><entry>188.96 (57)</entry><entry>179.69 (57)</entry><entry>2 (0.5-7)</entry><entry align="center">6.85 (118)</entry></row><row rowsep="0"><entry>Xyrem^® 2 x 2.25 g</entry><entry align="center">1^st dose: 33.41 (41)</entry><entry morerows="1" rowsep="1" align="center">214.32 (48)</entry><entry morerows="1" rowsep="1" align="center">202.78 (46)</entry><entry align="center">1^st dose: 1.0 (0.5-2)</entry><entry morerows="1" rowsep="1" align="center">9.24 (127)</entry></row><row><entry /><entry>2^nd dose: 65.91 (40)</entry><entry align="center">2^nd dose: 4.5 (4.33-6.5)</entry></row></tbody></tgroup></table></tables><tables id="tabl0037" num="0037"><table frame="all"><title>Table 6b. Mean plasma concentration of gamma-hydroxybutyrate (microgram/mL) versus time of finished composition of Example 4bis and Xyrem^®</title><tgroup cols="3"><colspec colnum="1" colname="col1" colwidth="24mm" align="center" /><colspec colnum="2" colname="col2" colwidth="97mm" align="center" /><colspec colnum="3" colname="col3" colwidth="43mm" align="center" /><thead valign="top"><row><entry>Time (hour)</entry><entry>Finished composition Example 4bis 4.5g (2 h after meal) (N=15)</entry><entry>Xyrem^® (2x2.25g) (N=15)</entry></row></thead><tbody><row><entry>0</entry><entry>0.00</entry><entry>0.00</entry></row><row><entry>0.5</entry><entry>23.80</entry><entry>27.44</entry></row><row><entry>1</entry><entry>33.26</entry><entry>28.97</entry></row><row><entry>1.5</entry><entry>35.60</entry><entry>26.12</entry></row><row><entry>2</entry><entry>35.57</entry><entry>21.11</entry></row><row><entry>2.5</entry><entry>33.81</entry><entry>13.93</entry></row><row><entry>3</entry><entry>30.96</entry><entry>10.25</entry></row><row><entry>3.5</entry><entry>28.73</entry><entry>6.92</entry></row><row><entry>4</entry><entry>26.06</entry><entry>42.32</entry></row><row><entry>4.5</entry><entry>23.27</entry><entry>57.33</entry></row><row><entry>5</entry><entry>18.68</entry><entry>52.27</entry></row><row><entry>5.5</entry><entry>16.67</entry><entry>43.55</entry></row><row><entry>6</entry><entry>15.55</entry><entry>35.20</entry></row><row><entry>6.5</entry><entry>13.07</entry><entry>27.44</entry></row><row><entry>7</entry><entry>11.75</entry><entry>19.36</entry></row><row><entry>7.5</entry><entry>9.20</entry><entry>13.88</entry></row><row><entry>8</entry><entry>6.85</entry><entry>9.24</entry></row><row><entry>10</entry><entry>1.94</entry><entry>2.64</entry></row><row><entry>12</entry><entry>NC</entry><entry>NC</entry></row></tbody></tgroup><tgroup cols="3" rowsep="0"><colspec colnum="1" colname="col1" colwidth="24mm" align="justify" /><colspec colnum="2" colname="col2" colwidth="97mm" /><colspec colnum="3" colname="col3" colwidth="43mm" /><tbody><row><entry namest="col1" nameend="col3">NC: Not Calculated</entry></row></tbody></tgroup></table></tables>

0292The 4.5g dose achieved a mean C_8h equal to about 6.85 microgram/mL which represents approximately 74.1% of the C_8h obtained for Xyrem^® dosed 2 x 2.25g. The ratio of AUC_8h to AUC_inf was about 0.89.

EXAMPLE 7. IN VITRO AND IN VIVO PHARMACOKINETIC STUDY OF A COMPARATIVE FORMULATION

0293A formulation having an in vitro dissolution profile comparable to the formulation reported in <figref idref="f0002">Figure 3</figref> of <patcit id="pcit0022" dnum="US8193211B"><text>US 8,193,211</text></patcit> was prepared to confirm the in vitro / in vivo correlations reported herein. Tables 7a-7c provide the qualitative and quantitative compositions of the MR microparticles, and mixtures of IR and MR microparticles. The physical structure of the microparticles showing the qualitative and quantitative composition of the IR and MR microparticles is depicted in <figref idref="f0012">Figure 23</figref>.

0294Briefly, sodium oxybate immediate release (IR) microparticles were prepared according to Example 1bis. Sodium oxybate modified release (MR) microparticles were prepared in two steps: <ul id="ul0006" list-style="none" compact="compact"><li>Step 1: 106.7g of water insoluble polymer Ethylcellulose (Ethocel^™ 20 Premium), 10.7g of polyvinylpyrrolidone (Plasdone^™ K30 from ISP), 10.7g of castor oil (from Olvea) and 5.3g of Polyoxyl 40 Hydrogenated Castor Oil (Kolliphor RH40 from BASF), were dissolved in a mixture of 828.0g of acetone, 552.0g of isopropanol and 153.3g of water. The solution was sprayed entirely on 400.0g of immediate release microparticles of sodium oxybate prepared above in a fluid bed spray coater apparatus Glatt G.P.C.G.1.1 with inlet temperature 57°C, spraying rate around 14.5 g per min and atomization pressure 2.5 bar. Microparticles with volume mean diameter of about 310 microns were obtained.</li><li>Step 2: 15.0g of Methacrylic acid copolymer Type C (Eudragit^™ L100-55 from Evonik), 30.0g of Methacrylic acid copolymer Type B (Eudragit^™ S100 from Evonik), 67.5g of Hydrogenated cottonseed oil (Lubritab^™), were dissolved in 1012.5g of isopropanol at 78°C. The solution was sprayed entirely on 450.0g of the above prepared microparticles in a fluid bed spray coater apparatus with an inlet temperature 47°C, spraying rate around 10.5g per min and atomization pressure 1.3 bar. MR microparticles were dried for two hours with inlet temperature set to 56°C. MR Microparticles with volume mean diameter of 335 microns were obtained.</li></ul>

0295The finished composition, which contains a 60:40 mixture of MR and IR microparticles calculated based on their sodium oxybate content, was prepared as follows: 326.69g of the above IR microparticles, 735.04g of the above MR microparticles, 23.74g of malic acid (D/L malic acid), 5.54g of xanthan gum (Xantural^™ 75 from Kelco), 5.54g of colloidal silicon dioxide (Aerosil^™ 200 from Degussa) and 11.08g of magnesium stearate were mixed. Individual samples of 8.40g (corresponding to a 4.5g dose of sodium oxybate with 40% of the dose as immediate-release fraction and 60% of the dose as modified release fraction) were weighed. <tables id="tabl0038" num="0038"><table frame="all"><title>Table 7a: Composition of MR Microparticles</title><tgroup cols="3"><colspec colnum="1" colname="col1" colwidth="59mm" /><colspec colnum="2" colname="col2" colwidth="43mm" /><colspec colnum="3" colname="col3" colwidth="47mm" /><thead valign="top"><row><entry align="center">Component</entry><entry align="center">Function</entry><entry align="center"><b>Quantity</b> per 2.25 g dose (g)</entry></row></thead><tbody><row><entry>IR Microparticles</entry><entry>Core of MR Microparticles</entry><entry>2.786</entry></row><row><entry>Ethylcellulose 20</entry><entry>Coating excipient</entry><entry>0.743</entry></row><row><entry>Povidone K30</entry><entry>Coating excipient</entry><entry>0.074</entry></row><row><entry>Polyoxyl 40 Hydrogenated Castor Oil</entry><entry>Coating excipient</entry><entry>0.037</entry></row><row><entry>Castor oil</entry><entry>Coating excipient</entry><entry>0.074</entry></row><row><entry>Hydrogenated Vegetable Oil</entry><entry>Coating excipient</entry><entry>0.557</entry></row><row><entry>Methacrylic acid Copolymer Type C</entry><entry>Coating excipient</entry><entry>0.124</entry></row><row><entry>Methacrylic acid Copolymer Type B</entry><entry>Coating excipient</entry><entry>0.248</entry></row><row><entry>Ethyl alcohol</entry><entry>Solvent</entry><entry>Eliminated during processing</entry></row><row><entry>Acetone</entry><entry>Solvent</entry><entry>Eliminated during processing</entry></row><row><entry>Water</entry><entry>Solvent</entry><entry>Eliminated during processing</entry></row><row><entry>Isopropyl alcohol</entry><entry>Solvent</entry><entry>Eliminated during processing</entry></row><row><entry>Total</entry><entry /><entry>4.644</entry></row></tbody></tgroup></table></tables><tables id="tabl0039" num="0039"><table frame="all"><title>Table 7b: Qualitative Composition of Finished Composition</title><tgroup cols="3"><colspec colnum="1" colname="col1" colwidth="39mm" /><colspec colnum="2" colname="col2" colwidth="70mm" /><colspec colnum="3" colname="col3" colwidth="44mm" align="center" /><thead valign="middle"><row><entry align="center">Component</entry><entry align="center">Function</entry><entry>Quantity per 4.5 g dose (g)</entry></row></thead><tbody><row valign="middle"><entry>MR microparticles</entry><entry>Modified release fraction of sodium oxybate</entry><entry>5.573</entry></row><row><entry valign="middle">IR microparticles</entry><entry>Immediate release fraction of sodium oxybate</entry><entry valign="middle">2.477</entry></row><row valign="middle"><entry>Malic acid</entry><entry>Acidifying agent</entry><entry>0.180</entry></row><row valign="middle"><entry>Xanthan gum</entry><entry>Suspending agent</entry><entry>0.042</entry></row><row valign="middle"><entry>Colloidal silicon dioxide</entry><entry>Gliding agent</entry><entry>0.042</entry></row><row valign="middle"><entry>Magnesium stearate</entry><entry>Lubricant</entry><entry>0.084</entry></row><row valign="middle"><entry>Total</entry><entry /><entry>8.398</entry></row></tbody></tgroup></table></tables><tables id="tabl0040" num="0040"><table frame="all"><title>Table 7c: Quantitative Composition of Finished Composition</title><tgroup cols="3"><colspec colnum="1" colname="col1" colwidth="59mm" align="center" /><colspec colnum="2" colname="col2" colwidth="42mm" align="center" /><colspec colnum="3" colname="col3" colwidth="44mm" align="center" /><thead valign="top"><row><entry>Component</entry><entry>Function</entry><entry>Quantity per 4.5 g dose (g)</entry></row></thead><tbody><row><entry>Sodium oxybate</entry><entry>Drug substance</entry><entry>4.5</entry></row><row><entry>Microcrystalline cellulose spheres</entry><entry>Core</entry><entry>0.836</entry></row><row><entry>Povidone K30</entry><entry>der and coating excipient</entry><entry>0.326</entry></row><row><entry>Hydroxypropyl cellulose</entry><entry>Top coat</entry><entry>0.248</entry></row><row><entry>Ethylcellulose 20</entry><entry>Coating excipient</entry><entry>0.892</entry></row><row><entry>Polyoxyl 40 Hydrogenated Castor Oil</entry><entry>Coating excipient</entry><entry>0.045</entry></row><row><entry>Castor oil</entry><entry>Coating excipient</entry><entry>0.089</entry></row><row><entry>Hydrogenated Vegetable Oil</entry><entry>Coating excipient</entry><entry>0.669</entry></row><row><entry>Methacrylic acid Copolymer Type C</entry><entry>Coating excipient</entry><entry>0.149</entry></row><row><entry>Methacrylic acid Copolymer Type B</entry><entry>Coating excipient</entry><entry>0.297</entry></row><row><entry>Malic acid</entry><entry>Acidifying agent</entry><entry>0.180</entry></row><row><entry>Xanthan gum</entry><entry>Suspending agent</entry><entry>0.042</entry></row><row><entry>Colloidal silicon dioxide</entry><entry>Gliding agent</entry><entry>0.042</entry></row><row><entry>Magnesium stearate</entry><entry>Lubricant</entry><entry>0.084</entry></row><row><entry>Total</entry><entry /><entry>8.398</entry></row></tbody></tgroup></table></tables>

0296The dissolution profile obtained for the MR microparticles in two sequential dissolution media (0.1N HCl for 2 hours then phosphate buffer pH 6.8) is shown in <figref idref="f0012">Figure 24</figref> and Table 7d. These data show that the dissolution profile of the MR microparticles produced according the comparative Example 7 was quite similar to the dissolution profile of <figref idref="f0002">Figure 3</figref> from <patcit id="pcit0023" dnum="US8193211B"><text>US 8,193,211</text></patcit>. In particular, the MR microparticles according to the comparative Example 7 do not release more than 80% of its sodium oxybate at 3 hours. <tables id="tabl0041" num="0041"><table frame="all"><title>Table 7d: Dissolution profile obtained for the MR microparticles of Example 7 in two sequential dissolution media (0.1N HCl for 2 hours then phosphate buffer pH 6.8)</title><tgroup cols="2"><colspec colnum="1" colname="col1" colwidth="83mm" align="center" /><colspec colnum="2" colname="col2" colwidth="81mm" align="center" /><thead valign="middle"><row><entry>Time (hour)</entry><entry>Example 7</entry></row></thead><tbody valign="middle"><row><entry>0</entry><entry>0</entry></row><row><entry>1</entry><entry>0</entry></row><row><entry>2</entry><entry>1</entry></row><row><entry>2.25</entry><entry>5</entry></row><row><entry>2.5</entry><entry>44</entry></row><row><entry>3</entry><entry>74</entry></row><row><entry>64</entry><entry>89</entry></row><row><entry>6</entry><entry>96</entry></row></tbody></tgroup></table></tables>

0297The finished composition of Comparative Example 7 was tested in the same pharmacokinetic study than the finished composition of Example 1 and 4. As summarized below (Tables 7e), 4.5 g nighttime dose of finished composition of the comparative Example 7 compared to twice-nightly doses of Xyrem^® (2 x 2.25 g) provided much less total exposure to sodium oxybate with a relative bioavailability of 67%. <tables id="tabl0042" num="0042"><table frame="all"><title>Table 7e. Pharmacokinetic Parameters of finished composition of Comparative Example 7 vs. Xyrem^®</title><tgroup cols="5"><colspec colnum="1" colname="col1" colwidth="51mm" align="center" /><colspec colnum="2" colname="col2" colwidth="27mm" align="center" /><colspec colnum="3" colname="col3" colwidth="30mm" align="center" /><colspec colnum="4" colname="col4" colwidth="29mm" align="center" /><colspec colnum="5" colname="col5" colwidth="26mm" align="center" /><thead valign="top"><row><entry /><entry>Mean C_max (µg/mL) (% CV)</entry><entry>Mean AUC_inf (h*µg/mL) (% CV)</entry><entry>Median T_max (hour) (min-max)</entry><entry>Mean C_8h (µg/mL) (% CV)</entry></row></thead><tbody><row><entry>Finished composition of Comparative Example 7 4.5g</entry><entry valign="middle">28.99 (45)</entry><entry valign="middle">143.90 (53)</entry><entry valign="middle">1.5 (0.5-8)</entry><entry valign="middle">7.79 (82)</entry></row><row rowsep="0" valign="middle"><entry>Xyrem^® 2 x</entry><entry>1st dose: 33.41 (41)</entry><entry>214.32 (48)</entry><entry>1st dose: 1.0 (0.5-2)</entry><entry>9.24 (127)</entry></row><row><entry>2.25 g</entry><entry>2nd dose: 65.91 (40)</entry><entry /><entry>2nd dose: 4.5 (4.33-6.5)</entry><entry /></row></tbody></tgroup></table></tables><tables id="tabl0043" num="0043"><table frame="all"><title>Table 7f. Mean plasma concentration (microgram/mL) of gamma-hydroxybutyrate versus time of finished composition of Comparative Example 7 and Xyrem^®</title><tgroup cols="5"><colspec colnum="1" colname="col1" colwidth="19mm" align="center" /><colspec colnum="2" colname="col2" colwidth="39mm" align="center" /><colspec colnum="3" colname="col3" colwidth="40mm" align="center" /><colspec colnum="4" colname="col4" colwidth="36mm" align="center" /><colspec colnum="5" colname="col5" colwidth="29mm" align="center" /><thead valign="top"><row><entry>Time (hour)</entry><entry>Comparative Example 7 @ 4.5g (2h after meal) pooled mean (N=27)</entry><entry>Comparative Example 7 @ 6.0g (2 h after meal) pooled mean (N=18)</entry><entry>Comparative Example 7 @ 7.5g (2 h after meal) (N=12)</entry><entry>@ Xyrem^® (2x2.25g) part I (N=15)</entry></row></thead><tbody><row><entry>0</entry><entry>0.00</entry><entry>0.00</entry><entry>0.00</entry><entry>0.00</entry></row><row><entry>0.5</entry><entry>18.84</entry><entry>25.54</entry><entry>31.40</entry><entry>27.44</entry></row><row><entry>1</entry><entry>23.93</entry><entry>35.80</entry><entry>46.78</entry><entry>28.97</entry></row><row><entry>1.5</entry><entry>24.31</entry><entry>38.59</entry><entry>58.29</entry><entry>26.12</entry></row><row><entry>2</entry><entry>24.32</entry><entry>40.78</entry><entry>57.47</entry><entry>21.11</entry></row><row><entry>2.5</entry><entry>23.10</entry><entry>38.03</entry><entry>52.25</entry><entry>13.93</entry></row><row><entry>3</entry><entry>20.05</entry><entry>35.76</entry><entry>49.00</entry><entry>10.25</entry></row><row><entry>3.5</entry><entry>17.47</entry><entry>33.99</entry><entry>45.66</entry><entry>6.92</entry></row><row><entry>4</entry><entry>16.48</entry><entry>30.47</entry><entry>40.52</entry><entry>0.00</entry></row><row><entry>4.5</entry><entry>15.44</entry><entry>26.87</entry><entry>37.70</entry><entry>57.33</entry></row><row><entry>5</entry><entry>14.10</entry><entry>25.59</entry><entry>36.82</entry><entry>52.27</entry></row><row><entry>5.5</entry><entry>12.60</entry><entry>24.63</entry><entry>35.93</entry><entry>43.55</entry></row><row><entry>6</entry><entry>11.68</entry><entry>23.90</entry><entry>34.47</entry><entry>35.20</entry></row><row><entry>6.5</entry><entry>11.45</entry><entry>23.98</entry><entry>31.60</entry><entry>27.44</entry></row><row><entry>7</entry><entry>10.64</entry><entry>20.94</entry><entry>31.89</entry><entry>19.36</entry></row><row><entry>7.5</entry><entry>9.35</entry><entry>17.93</entry><entry>29.69</entry><entry>13.88</entry></row><row><entry>8</entry><entry>7.79</entry><entry>14.36</entry><entry>25.80</entry><entry>9.24</entry></row><row><entry>10</entry><entry>1.98</entry><entry>3.71</entry><entry>11.00</entry><entry>2.64</entry></row><row><entry>12</entry><entry>0.59</entry><entry>0.78</entry><entry>3.63</entry><entry>NC</entry></row></tbody></tgroup><tgroup cols="5" rowsep="0"><colspec colnum="1" colname="col1" colwidth="19mm" align="justify" /><colspec colnum="2" colname="col2" colwidth="39mm" /><colspec colnum="3" colname="col3" colwidth="40mm" /><colspec colnum="4" colname="col4" colwidth="36mm" /><colspec colnum="5" colname="col5" colwidth="29mm" /><tbody><row><entry namest="col1" nameend="col5">NC: not calculated</entry></row></tbody></tgroup></table></tables>

0298The pharmacokinetic profiles of single 6 g and 7.5 g doses of the finished composition produced according to comparative Example 7 were also generated. Table 7g provides data on a single 4.5 g, 6 g and 7.5 g dose, showing effects on C_max, C_8h, AUC_8h and AUC_inf related to dose strength. <tables id="tabl0044" num="0044"><table frame="all"><title>Table 7g. Pharmacokinetic Parameters of 4.5g, 6g, and 7.5g of finished composition produced according Comparative Example 7</title><tgroup cols="6"><colspec colnum="1" colname="col1" colwidth="32mm" align="center" /><colspec colnum="2" colname="col2" colwidth="25mm" align="center" /><colspec colnum="3" colname="col3" colwidth="27mm" align="center" /><colspec colnum="4" colname="col4" colwidth="27mm" align="center" /><colspec colnum="5" colname="col5" colwidth="27mm" align="center" /><colspec colnum="6" colname="col6" colwidth="24mm" align="center" /><thead valign="top"><row><entry>Finished composition Comparative of Example 7</entry><entry>Mean C_max (µg/mL) (% CV)</entry><entry>Mean AUCinf (h*µg/mL) (% CV)</entry><entry>Mean AUC_8h (h*/µg/mL) (% CV)</entry><entry>Median T_max (min-max) (h) (% CV)</entry><entry>Mean C_8h (µg/mL) (% CV)</entry></row></thead><tbody><row><entry>4.5 g</entry><entry>28.98 (45)</entry><entry>143.90 (53)</entry><entry>128.83 (55)</entry><entry>1.5 (0.5-8)</entry><entry>7.79 (82)</entry></row><row><entry>6 g</entry><entry>45.64 (35)</entry><entry>248.24 (47)</entry><entry>225.00 (47)</entry><entry>2 (0.5-6.5)</entry><entry>14.36 (77)</entry></row><row><entry>7.5 g</entry><entry>63.31 (33)</entry><entry>379.83 (54)</entry><entry>316.18 (48)</entry><entry>1.75 (1-4.5)</entry><entry>25.80 (74)</entry></row></tbody></tgroup></table></tables>

EXAMPLE 8. ALTERNATIVE FORMULATIONS

0299Example 8.1: Modified release formulation of gamma-hydroxybutyrate comprising immediate release microparticles of potassium salt of gamma-hydroxybutyric acid and modified release microparticles of sodium salt of gamma-hydroxybutyric acid (sodium oxybate).

0300Immediate release (IR) microparticles of potassium salt of gamma-hydroxybutyric acid can be prepared as follows: 1615.0 g of potassium salt of gamma-hydroxybutyric acid and 85.0 g of polyvinylpyrrolidone (Povidone K30- Plasdone^™ K29/32 from ISP) are solubilized in 1894.3 g of absolute ethyl alcohol and 1262.9 g of water. The solution is entirely sprayed onto 300 g of microcrystalline cellulose spheres (Cellets^™ 127) in a fluid bed spray coater apparatus.

0301Immediate release (IR) microparticles of sodium salt of gamma-hydroxybutyric acid were prepared as follows: 1615.0g of sodium salt of gamma-hydroxybutyric acid and 85.0g of polyvinylpyrrolidone (Povidone K30 - Plasdone K29/32 from ISP) were solubilized in 1894.3g of absolute ethyl alcohol and 1262.9g of water. The solution was entirely sprayed onto 300g of microcrystalline cellulose spheres (Cellets^™ 127 from Pharmatrans Sanaq) in a fluid bed spray coater apparatus.

0302Sodium oxybate modified release (MR) microparticles are prepared as follows: 22.8 g of methacrylic acid copolymer Type C (Eudragit^™ L100-55), 45.8 g of methacrylic acid copolymer Type B (Eudragit^™ S100), 102.9 g of hydrogenated cottonseed oil (Lubritab^™), are dissolved in 1542.9 g of isopropanol at 78°C. The solution is sprayed entirely onto 400.0 g of the sodium oxybate IR microparticles described above in a fluid bed spray coater apparatus with an inlet temperature of 48° C, spraying rate around 11 g per min and atomization pressure of 1.3 bar. MR microparticles are dried for two hours with inlet temperature set to 56°C. MR microparticles with mean volume diameter of about 320 microns were obtained.

0303The finished formulation, which contains a 50:50 mixture of MR and IR microparticles calculated on their gamma-hydroxybutyrate content, can be prepared as follows: 398.51 g of the above IR microparticles, 504.80 g of the above MR microparticles, 16.09 g of D/L malic acid, 6.34 g of xanthan gum (Xantural^™ 75 from Kelco), 9.51 g of carrageenan gum (Viscarin^™ PH209 from FMC Biopolymer), 9.51 g of hydroxyethylcellulose (Natrosol^™ 250M from Ashland) and 4.75 g of magnesium stearate were mixed. Individual samples of 7.49 g of the mixture (amount equivalent to a 4.5g dose of sodium oxybate with half of the dose as immediate-release fraction and half of the dose as modified release fraction) were weighed. <tables id="tabl0045" num="0045"><table frame="all"><title>Table 8a: Composition of IR Microparticles of gamma-hydroxybutyrate of example 8.1</title><tgroup cols="3"><colspec colnum="1" colname="col1" colwidth="57mm" /><colspec colnum="2" colname="col2" colwidth="61mm" /><colspec colnum="3" colname="col3" colwidth="46mm" /><thead valign="top"><row><entry align="center">Component</entry><entry align="center">Function</entry><entry align="center">Quantity per 2.25 g dose (g)</entry></row></thead><tbody><row><entry>Potassium salt of hydroxybutyric acid</entry><entry>Drug substance</entry><entry>2.537</entry></row><row><entry>Microcrystalline cellulose spheres</entry><entry>Core</entry><entry>0.471</entry></row><row><entry>Povidone K30</entry><entry>Binder and excipient in diffusion coating</entry><entry>0.134</entry></row><row><entry>Ethyl alcohol</entry><entry>Solvent</entry><entry>Eliminated during processing</entry></row><row><entry>Purified water</entry><entry>Solvent</entry><entry>Eliminated during processing</entry></row><row><entry>Total</entry><entry /><entry>3.142</entry></row></tbody></tgroup></table></tables><tables id="tabl0046" num="0046"><table frame="all"><title>Table 8b: Composition of MR Microparticles of gamma-hydroxybutyrate of example 8.1</title><tgroup cols="3"><colspec colnum="1" colname="col1" colwidth="57mm" /><colspec colnum="2" colname="col2" colwidth="31mm" /><colspec colnum="3" colname="col3" colwidth="47mm" /><thead valign="top"><row><entry align="center">Component</entry><entry align="center">Function</entry><entry align="center">Quantity per 2.25 g dose (g)</entry></row></thead><tbody><row><entry>Sodium oxybate</entry><entry>Drug substance</entry><entry>2.25</entry></row><row><entry>Povidone K30</entry><entry>Binder</entry><entry>0.118</entry></row><row><entry>Microcrystalline cellulose spheres</entry><entry>Core</entry><entry>0.419</entry></row><row><entry>Hydrogenated Vegetable Oil</entry><entry>Coating excipient</entry><entry>0.717</entry></row><row><entry>Methacrylic acid Copolymer Type C</entry><entry>Coating excipient</entry><entry>0.159</entry></row><row><entry>Methacrylic acid Copolymer Type B</entry><entry>Coating excipient</entry><entry>0.318</entry></row><row><entry>Ethyl alcohol</entry><entry>Solvent</entry><entry>Eliminated during processing</entry></row><row><entry>Acetone</entry><entry>Solvent</entry><entry>Eliminated during processing</entry></row><row><entry>Water</entry><entry>Solvent</entry><entry>Eliminated during processing</entry></row><row><entry>Isopropyl alcohol</entry><entry>Solvent</entry><entry>Eliminated during processing</entry></row><row><entry>Total</entry><entry /><entry>3.981</entry></row></tbody></tgroup></table></tables><tables id="tabl0047" num="0047"><table frame="all"><title>Table 8c: Qualitative Composition of Finished Formulation of Example 8.1</title><tgroup cols="3"><colspec colnum="1" colname="col1" colwidth="36mm" /><colspec colnum="2" colname="col2" colwidth="109mm" /><colspec colnum="3" colname="col3" colwidth="19mm" align="center" /><thead valign="middle"><row><entry align="center">Component</entry><entry align="center">Function</entry><entry>Quantity per 4.5 g dose (g)</entry></row></thead><tbody><row valign="middle"><entry>MR microparticles</entry><entry>Modified release fraction of sodium oxybate</entry><entry>3.981</entry></row><row><entry valign="middle">IR microparticles</entry><entry>Immediate release fraction of potassium salt of gamma-hydroxybutyric acid</entry><entry valign="middle">3.142</entry></row><row valign="middle"><entry>Malic acid</entry><entry>Acidifying agent</entry><entry>0.127</entry></row><row valign="middle"><entry>Xanthan gum</entry><entry>Suspending agent</entry><entry>0.050</entry></row><row valign="middle"><entry>Hydroxyethylcellulose</entry><entry>Suspending agent</entry><entry>0.075</entry></row><row valign="middle"><entry>Carrageenan gum</entry><entry>Suspending agent</entry><entry>0.075</entry></row><row valign="middle"><entry>Magnesium stearate</entry><entry>Lubricant</entry><entry>0.037</entry></row><row valign="middle"><entry>Total</entry><entry /><entry>7.487</entry></row></tbody></tgroup></table></tables><tables id="tabl0048" num="0048"><table frame="all"><title>Table 8d: Quantitative Composition of Finished Formulation of Example 8.1</title><tgroup cols="3"><colspec colnum="1" colname="col1" colwidth="70mm" /><colspec colnum="2" colname="col2" colwidth="32mm" align="center" /><colspec colnum="3" colname="col3" colwidth="44mm" align="center" /><thead valign="middle"><row><entry align="center">Component</entry><entry>Function</entry><entry>Quantity per 4.5 g dose (g)</entry></row></thead><tbody><row valign="middle"><entry>Sodium oxybate</entry><entry>Drug substance</entry><entry>2.25</entry></row><row valign="middle"><entry>Potassium salt of gamma-hydroxybutyric acid</entry><entry>Drug substance</entry><entry>2.537</entry></row><row valign="middle"><entry>Microcrystalline cellulose spheres</entry><entry>Core</entry><entry>0.890</entry></row><row valign="middle"><entry>Povidone K30</entry><entry>Binder</entry><entry>0.252</entry></row><row valign="middle"><entry>Hydrogenated Vegetable Oil</entry><entry>Coating excipient</entry><entry>0.717</entry></row><row><entry valign="middle">Methacrylic acid Copolymer Type C</entry><entry>Coating excipient</entry><entry valign="middle">0.159</entry></row><row><entry valign="middle">Methacrylic acid Copolymer Type B</entry><entry>Coating excipient</entry><entry valign="middle">0.318</entry></row><row valign="middle"><entry>Malic acid</entry><entry>Acidifying agent</entry><entry>0.127</entry></row><row valign="middle"><entry>Xanthan gum</entry><entry>Suspending agent</entry><entry>0.050</entry></row><row valign="middle"><entry>Hydroxyethylcellulose</entry><entry>Suspending agent</entry><entry>0.075</entry></row><row valign="middle"><entry>Carrageenan gum</entry><entry>Suspending agent</entry><entry>0.075</entry></row><row valign="middle"><entry>Magnesium stearate</entry><entry>Lubricant</entry><entry>0.037</entry></row><row valign="middle"><entry align="center">Total</entry><entry /><entry>7.487</entry></row></tbody></tgroup></table></tables>

0304Example 8.2: Modified release formulation of gamma-hydroxybutyrate comprising immediate release microparticles of potassium salt of gamma-hydroxybutyric acid, immediate release microparticles of magnesium salt of gamma-hydroxybutyric acid, immediate release microparticles of calcium salt of gamma-hydroxybutyric acid and modified release microparticles of sodium salt of gamma-hydroxybutyric acid (sodium oxybate).

0305Immediate release (IR) microparticles of potassium salt of gamma-hydroxybutyric acid are prepared according to example 8.1.

0306Immediate release (IR) microparticles of magnesium salt of gamma-hydroxybutyric acid or calcium salt of gamma-hydroxybutyric acid can be prepared using the same manufacturing process by replacing the potassium salt of gamma-hydroxybutyric acid by the same weight of respectively magnesium salt of gamma-hydroxybutyric acid or calcium salt of gamma-hydroxybutyric acid.

0307Sodium oxybate modified release (MR) microparticles are prepared according to example 8.1.

0308The finished formulation, which contains a 50:50 mixture of MR and IR microparticles calculated on their gamma-hydroxybutyrate content, can be prepared as follows: 132.84 g of the IR microparticles of potassium salt of gamma-hydroxybutyric acid, 215.32 g of the IR microparticles of magnesium salt of gamma-hydroxybutyric acid, 230.05 g of the IR microparticles of calcium salt of gamma-hydroxybutyric acid, 504.80 g of the MR microparticles of sodium oxybate, 23.35 g of D/L malic acid, 6.34 g of xanthan gum (Xantural^™ 75 from Kelco), 9.51 g of carrageenan gum (Viscarin^™ PH209 from FMC Biopolymer), 9.51 g of hydroxyethylcellulose (Natrosol^™ 250M from Ashland) and 5.69 g of magnesium stearate were mixed. Individual samples of 8.96 g of the mixture (amount equivalent to a 4.5g dose of sodium oxybate with half of the dose as immediate-release fraction and half of the dose as modified release fraction) were weighed. <tables id="tabl0049" num="0049"><table frame="all"><title>Table 8e: Qualitative Composition of Finished Formulation of Example 8.2</title><tgroup cols="3"><colspec colnum="1" colname="col1" colwidth="36mm" /><colspec colnum="2" colname="col2" colwidth="111mm" /><colspec colnum="3" colname="col3" colwidth="17mm" align="center" /><thead valign="middle"><row><entry align="center">Component</entry><entry align="center">Function</entry><entry>Quantity per 4.5 g dose (g)</entry></row></thead><tbody><row><entry valign="middle">MR microparticles</entry><entry>Modified release fraction of sodium oxybate</entry><entry valign="middle">3.981</entry></row><row><entry valign="middle">IR microparticles</entry><entry>Immediate release fraction of potassium salt of gamma-hydroxybutyric acid + immediate release fraction of magnesium salt of gamma-hydroxybutyric acid + immediate release fraction of calcium salt of gamma-hydroxybutyric acid</entry><entry valign="middle">4.559</entry></row><row valign="middle"><entry>Malic acid</entry><entry>Acidifying agent</entry><entry>0.184</entry></row><row valign="middle"><entry>Xanthan gum</entry><entry>Suspending agent</entry><entry>0.050</entry></row><row valign="middle"><entry>Hydroxyethylcellulose</entry><entry>Suspending agent</entry><entry>0.075</entry></row><row valign="middle"><entry>Carrageenan gum</entry><entry>Suspending agent</entry><entry>0.075</entry></row><row valign="middle"><entry>Magnesium stearate</entry><entry>Lubricant</entry><entry>0.045</entry></row><row valign="middle"><entry>Total</entry><entry /><entry>8.97</entry></row></tbody></tgroup></table></tables><tables id="tabl0050" num="0050"><table frame="all"><title>Table 8f: Quantitative Composition of Finished Formulation of Example 8.2</title><tgroup cols="3"><colspec colnum="1" colname="col1" colwidth="72mm" /><colspec colnum="2" colname="col2" colwidth="32mm" align="center" /><colspec colnum="3" colname="col3" colwidth="44mm" align="center" /><thead valign="middle"><row><entry align="center">Component</entry><entry>Function</entry><entry>Quantity per 4.5 g dose (g)</entry></row></thead><tbody valign="middle"><row><entry>Sodium oxybate</entry><entry>Drug substance</entry><entry>2.25</entry></row><row><entry>Potassium salt of gamma-hydroxybutyric acid</entry><entry>Drug substance</entry><entry>0.84</entry></row><row><entry>Magnesium salt of gamma-hydroxybutyric acid</entry><entry>Drug substance</entry><entry>1.37</entry></row><row><entry>Calcium salt of gamma-hydroxybutyric acid</entry><entry>Drug substance</entry><entry>1.46</entry></row><row><entry>Microcrystalline cellulose spheres</entry><entry>Core</entry><entry>1.102</entry></row><row><entry>Povidone K30</entry><entry>Binder</entry><entry>0.312</entry></row><row><entry>Hydrogenated Vegetable Oil</entry><entry>Coating excipient</entry><entry>0.717</entry></row><row><entry>Methacrylic acid Copolymer Type C</entry><entry>Coating excipient</entry><entry>0.159</entry></row><row><entry>Methacrylic acid Copolymer Type B</entry><entry>Coating excipient</entry><entry>0.318</entry></row><row><entry>Malic acid</entry><entry>Acidifying agent</entry><entry>0.184</entry></row><row><entry>Xanthan gum</entry><entry>Suspending agent</entry><entry>0.050</entry></row><row><entry>Hydroxyethylcellulose</entry><entry>Suspending agent</entry><entry>0.075</entry></row><row><entry>Carrageenan gum</entry><entry>Suspending agent</entry><entry>0.075</entry></row><row><entry>Magnesium stearate</entry><entry>Lubricant</entry><entry>0.045</entry></row><row><entry align="center">Total</entry><entry /><entry>8.96</entry></row></tbody></tgroup></table></tables>

EXAMPLE 8.3: MODIFIED RELEASE FORMULATION OF GAMMA-HYDROXYBUTYRATE COMPRISING IMMEDIATE RELEASE MICROPARTICLES OF POTASSIUM SALT OF GAMMA-HYDROXYBUTYRIC ACID AND MODIFIED RELEASE MICROPARTICLES OF CALCIUM SALT OF GAMMA-HYDROXYBUTYRIC ACID.

0309Immediate release (IR) microparticles of potassium salt of gamma-hydroxybutyric acid are prepared according to example 8.1.

0310Immediate release (IR) microparticles of calcium salt of gamma-hydroxybutyric acid can be prepared using the manufacturing process described in example 8.1 for immediate release (IR) microparticles of potassium salt of gamma-hydroxybutyric acid by replacing the potassium salt of gamma-hydroxybutyric acid by the same weight of calcium salt of gamma-hydroxybutyric acid. These Immediate release (IR) microparticles of calcium salt of gamma-hydroxybutyric acid are used to manufacture modified release (MR) microparticles of calcium salt of gamma-hydroxybutyric acid as follows: 22.8 g of methacrylic acid copolymer Type C (Eudragit^™ L100-55), 45.8 g of methacrylic acid copolymer Type B (Eudragit^™ S100), 102.9 g of hydrogenated cottonseed oil (Lubritab^™), are dissolved in 1542.9 g of isopropanol at 78°C. The solution is sprayed entirely onto 400.0 g of the immediate release microparticles of calcium salt of gamma-hydroxybutyric acid described above in a fluid bed spray coater apparatus with an inlet temperature of 48° C, spraying rate around 11 g per min and atomization pressure of 1.3 bar. MR microparticles are dried for two hours with inlet temperature set to 56°C.

0311The finished formulation, which contains a 50:50 mixture of MR and IR microparticles calculated on their gamma-hydroxybutyrate content, can be prepared as follows: 398.53 g of the IR microparticles of potassium salt of gamma-hydroxybutyric acid, 492.87 g of the MR microparticles of sodium oxybate, 16.10 g of D/L malic acid, 6.34 g of xanthan gum (Xantural^™ 75 from Kelco), 9.51 g of carrageenan gum (Viscarin^™ PH209 from FMC Biopolymer), 9.51 g of hydroxyethylcellulose (Natrosol^™ 250M from Ashland) and 4.69 g of magnesium stearate were mixed. Individual samples of 7.39 g of the mixture (amount equivalent to a 4.5g dose of sodium oxybate with half of the dose as immediate-release fraction and half of the dose as modified release fraction) were weighed. <tables id="tabl0051" num="0051"><table frame="all"><title>Table 8g: Qualitative Composition of Finished Formulation of Example 8.3</title><tgroup cols="3"><colspec colnum="1" colname="col1" colwidth="36mm" /><colspec colnum="2" colname="col2" colwidth="109mm" /><colspec colnum="3" colname="col3" colwidth="19mm" align="center" /><thead valign="middle"><row><entry align="center">Component</entry><entry align="center">Function</entry><entry>Quantity per 4.5 g dose (g)</entry></row></thead><tbody valign="middle"><row><entry>MR microparticles</entry><entry>Modified release fraction of calcium salt of gamma-hydroxybutyric acid</entry><entry>3.887</entry></row><row><entry>IR microparticles</entry><entry>Immediate release fraction of potassium salt of gamma-hydroxybutyric acid</entry><entry>3.143</entry></row><row><entry>Malic acid</entry><entry>Acidifying agent</entry><entry>0.127</entry></row><row><entry>Xanthan gum</entry><entry>Suspending agent</entry><entry>0.050</entry></row><row><entry>Hydroxyethylcellulose</entry><entry>Suspending agent</entry><entry>0.075</entry></row><row><entry>Carrageenan gum</entry><entry>Suspending agent</entry><entry>0.075</entry></row><row><entry>Magnesium stearate</entry><entry>Lubricant</entry><entry>0.037</entry></row><row><entry>Total</entry><entry /><entry>7.39</entry></row></tbody></tgroup></table></tables><tables id="tabl0052" num="0052"><table frame="all"><title>Table 8h: Quantitative Composition of Finished Formulation of Example 8.3</title><tgroup cols="3"><colspec colnum="1" colname="col1" colwidth="70mm" /><colspec colnum="2" colname="col2" colwidth="32mm" align="center" /><colspec colnum="3" colname="col3" colwidth="44mm" align="center" /><thead valign="middle"><row><entry align="center">Component</entry><entry>Function</entry><entry>Quantity per 4.5 g dose (g)</entry></row></thead><tbody valign="middle"><row><entry>Potassium salt of gamma-hydroxybutyric acid</entry><entry>Drug substance</entry><entry>2.54</entry></row><row><entry>Calcium salt of gamma-hydroxybutyric acid</entry><entry>Drug substance</entry><entry>2.19</entry></row><row><entry>Microcrystalline cellulose spheres</entry><entry>Core</entry><entry>0.880</entry></row><row><entry>Povidone K30</entry><entry>Binder</entry><entry>0.249</entry></row><row><entry>Hydrogenated Vegetable Oil</entry><entry>Coating excipient</entry><entry>0.700</entry></row><row><entry>Methacrylic acid Copolymer Type C</entry><entry>Coating excipient</entry><entry>0.155</entry></row><row><entry>Methacrylic acid Copolymer Type B</entry><entry>Coating excipient</entry><entry>0.311</entry></row><row><entry>Malic acid</entry><entry>Acidifying agent</entry><entry>0.127</entry></row><row><entry>Xanthan gum</entry><entry>Suspending agent</entry><entry>0.050</entry></row><row><entry>Hydroxyethylcellulose</entry><entry>Suspending agent</entry><entry>0.075</entry></row><row><entry>Carrageenan gum</entry><entry>Suspending agent</entry><entry>0.075</entry></row><row><entry>Magnesium stearate</entry><entry>Lubricant</entry><entry>0.037</entry></row><row><entry>Total</entry><entry /><entry>7.39</entry></row></tbody></tgroup></table></tables>

EXAMPLE 9. ALTERNATIVE FORMULATIONS WITH DIFFERING CONCENTRATIONS OF ACIDIC AGENTS

0312Different prototypes were developed to evaluate the effect of acidic agent on the dissolution stability of the formulation dispersed in water. Experimental data with 0.8%, 1.6% and 15% malic acid are detailed below.

Example 9.1 -- 1.6% malic acid

0313IR particles were prepared as follows: 1615.0g of Sodium Oxybate and 85.0g of water soluble polymer polyvinylpyrrolidone (Povidone - Plasdone^™ K30 from ISP) were solubilized in 1894.3g of absolute ethyl alcohol and 1262.9g of water. The solution was entirely sprayed onto 300g of microcrystalline cellulose spheres (Cellets^™ 127 from Pharmatrans) in a fluid bed spray coater apparatus GPCG1.1. Sodium oxybate IR particles with mean diameter of 268 microns were obtained.

0314MR coated particles were prepared as follows: 39.9g of Methacrylic acid copolymer Type C (Eudragit^™ L100-55 from Evonik), 80.1g of Methacrylic acid copolymer Type B (Eudragit^™ S100 from Evonik), 180.0g of Hydrogenated cottonseed oil (Lubritab^™ from JRS), were dissolved in 2700.0g of isopropanol at 78°C. The solution was sprayed entirely on 700.0g of IR particles in a fluid bed spray coater apparatus Glatt^™ G.P.C.G.1.1 with inlet temperature 49°C, spraying rate around 11.6g per min and atomization pressure 1.6 bar. MR microparticles were dried for 2 hours with inlet temperature set to 56°C. Sodium oxybate MR coated particles with mean diameter of 324 microns were obtained.

0315The finished composition, which contains a 50:50 mixture of MR and IR particles calculated on their sodium oxybate content, was prepared as follows: 655.1g of the above IR particles, 936.4g of the above MR particles, 26.5g of Malic acid (D/L malic acid regular from Bartek), 11.7g of xanthan gum (Xantural^™ 75 from CP Kelco), 17.6g of carragenan gum (Viscarin^™ PH209 from FMC Biopolymer), 17.6g of hydroxyethylcellulose (Natrosol^™ 250M from Ashland ) and 8.2g of magnesium stearate (from Peter Greven) were mixed in a Roue-Roehn mixer. Individual doses of 7.11g (corresponding to a 4.5g dose with half of the dose as immediate-release fraction and half of the dose as modified release fraction) were weighed.

0316<figref idref="f0015">Figure 29</figref> and Table 9a below depict dissolution profiles determined in 0.1N HCl using a USP apparatus 2. The dissolution medium was maintained at 37.0 ± 0.5°C and the rotating paddle speed was fixed at 75 rpm. Single dose units were poured in a container containing 50 mL of tap water. After 5 and 15 minutes, the suspension was poured in the dissolution vessel containing 840 mL of 0.1N HCl dissolution medium. 10 mL of water were used to rinse the container and were added to the dissolution vessel. <tables id="tabl0053" num="0053"><table frame="all"><title>Table 9a</title><tgroup cols="3"><colspec colnum="1" colname="col1" colwidth="18mm" align="center" /><colspec colnum="2" colname="col2" colwidth="59mm" align="center" /><colspec colnum="3" colname="col3" colwidth="60mm" align="center" /><thead valign="middle"><row><entry>Time (h)</entry><entry>% dissolved 5 min reconstitution time</entry><entry>% dissolved 15 min reconstitution time</entry></row></thead><tbody valign="middle"><row><entry>0</entry><entry>0</entry><entry>0</entry></row><row><entry>0,25</entry><entry>47</entry><entry>48</entry></row><row><entry>1</entry><entry>53</entry><entry>52</entry></row><row><entry>3</entry><entry>53</entry><entry>53</entry></row><row><entry>6</entry><entry>55</entry><entry>54</entry></row><row><entry>8</entry><entry>59</entry><entry>60</entry></row><row><entry>10</entry><entry>74</entry><entry>77</entry></row><row><entry>12</entry><entry>87</entry><entry>88</entry></row><row><entry>16</entry><entry>96</entry><entry>97</entry></row><row><entry>20</entry><entry>97</entry><entry>98</entry></row></tbody></tgroup></table></tables>

Example 9.2 -- 0.8% malic acid

0317IR particles were prepared as follows: 1615.0g of Sodium Oxybate and 85.0g of water soluble polymer polyvinylpyrrolidone (Povidone - Plasdone^™ K30 from ISP) were solubilized in 1894.3g of absolute ethyl alcohol and 1262.9g of water. The solution was entirely sprayed onto 300g of microcrystalline cellulose spheres (Cellets^™ 127 from Pharmatrans) in a fluid bed spray coater apparatus GPCG1.1. Sodium oxybate IR particles with mean diameter of 273 microns were obtained.

0318MR coated particles were prepared as follows: 39.9g of Methacrylic acid copolymer Type C (Eudragit^™ L100-55 from Evonik), 80.1g of Methacrylic acid copolymer Type B (Eudragit^™ S100 from Evonik), 180.0g of Hydrogenated cottonseed oil (Lubritab^™ from JRS), were dissolved in 2700.0g of isopropanol at 78°C. The solution was sprayed entirely on 700.0g of IR particles in a fluid bed spray coater apparatus Glatt^™ G.P.C.G.1.1 with inlet temperature 47°C, spraying rate around 10.7g per min and atomization pressure 1.6 bar. MR microparticles were dried for 2 hours with inlet temperature set to 60°C. Sodium oxybate MR coated particles with mean diameter of 309 microns were obtained.

0319The finished composition, which contains a 50:50 mixture of MR and IR particles calculated on their sodium oxybate content, was prepared as follows: 100.0g of the above IR particles, 142.9g of the above MR particles, 2.0g of Malic acid (D/L malic acid regular from Bartek), 1.2g of xanthan gum (Xantural^™ 75 from CP Kelco), 1.2g of hydrophilic fumed silica (Aerosil^™ 200 from Degussa) and 2.5g of magnesium stearate (from Peter Greven) were mixed in a Roue-Roehn mixer. Individual doses of 6.93g (corresponding to a 4.5g dose with half of the dose as immediate-release fraction and half of the dose as modified release fraction) were weighed.

0320<figref idref="f0015">Figure 30</figref> and Table 9b below depict dissolution profiles determined in 0.1N HCl using a USP apparatus 2. The dissolution medium was maintained at 37.0 ± 0.5°C and the rotating paddle speed was fixed at 75 rpm. Single dose units were poured in a container containing 50 mL of tap water. After 5 and 15 minutes, the suspension was poured in the dissolution vessel containing 840 mL of 0.1N HCl dissolution medium. 10 mL of water were used to rinse the container and were added to the dissolution vessel. <tables id="tabl0054" num="0054"><table frame="all"><title>Table 9b</title><tgroup cols="3"><colspec colnum="1" colname="col1" colwidth="18mm" align="center" /><colspec colnum="2" colname="col2" colwidth="59mm" align="center" /><colspec colnum="3" colname="col3" colwidth="60mm" align="center" /><thead valign="middle"><row><entry>Time (h)</entry><entry>% dissolved 5 min reconstitution time</entry><entry>% dissolved 15 min reconstitution time</entry></row></thead><tbody valign="middle"><row><entry>0</entry><entry>0</entry><entry>0</entry></row><row><entry>0,25</entry><entry>51</entry><entry>51</entry></row><row><entry>1</entry><entry>51</entry><entry>52</entry></row><row><entry>3</entry><entry>51</entry><entry>53</entry></row><row><entry>6</entry><entry>52</entry><entry>62</entry></row><row><entry>8</entry><entry>60</entry><entry>86</entry></row><row><entry>10</entry><entry>77</entry><entry>96</entry></row><row><entry>12</entry><entry>90</entry><entry>98</entry></row><row><entry>16</entry><entry>98</entry><entry>98</entry></row></tbody></tgroup></table></tables>

Example 9.3 -- 15% malic acid

0321IR particles were prepared as follows: 1615.0g of Sodium Oxybate and 85.0g of water soluble polymer polyvinylpyrrolidone (Povidone - Plasdone^™ K30 from ISP) were solubilized in 1894.3g of absolute ethyl alcohol and 1262.9g of water. The solution was entirely sprayed onto 300g of microcrystalline cellulose spheres (Cellets^™ 127 from Pharmatrans) in a fluid bed spray coater apparatus GPCG1.1. Sodium oxybate IR particles with mean diameter of 255 microns were obtained.

0322MR coated particles were prepared as follows: 22.8g of Methacrylic acid copolymer Type C (Eudragit^™ L100-55 from Evonik), 45.8g of Methacrylic acid copolymer Type B (Eudragit^™ S100 from Evonik), 102.9g of Hydrogenated cottonseed oil (Lubritab^™ from JRS), were dissolved in 1544.8g of isopropanol at 78°C. The solution was sprayed entirely on 400.0g of IR particles in a fluid bed spray coater apparatus Glatt^™ G.P.C.G.1.1 with inlet temperature 49°C, spraying rate around 12.0g per min and atomization pressure 1.3 bar. MR microparticles were dried for 2 hours with inlet temperature set to 56°C. Sodium oxybate MR coated particles with mean diameter of 298 microns were obtained.

0323The finished composition, which contains a 50:50 mixture of MR and IR particles calculated on their sodium oxybate content, was prepared as follows: 36.2g of the above IR particles, 51.8g of the above MR particles, 16.1g of Malic acid (D/L malic acid regular from Bartek), 0.7g of xanthan gum (Xantural^™ 75 from CP Kelco), 1.0g of carragenan gum (Viscarin^™ PH209 from FMC Biopolymer), 1.0g of hydroxyethylcellulose (Natrosol^™ 250M from Ashland ) and 0.6g of magnesium stearate (from Peter Greven) were mixed in a Roue-Roehn mixer. Individual doses of 8.25g (corresponding to a 4.5g dose with half of the dose as immediate-release fraction and half of the dose as modified release fraction) were weighed.

0324<figref idref="f0016">Figure 31</figref> and Table 9c below depict dissolution profiles determined in 0.1N HCl using a USP apparatus 2. The dissolution medium was maintained at 37.0 ± 0.5°C and the rotating paddle speed was fixed at 75 rpm. Single dose units were poured in a container containing 50 mL of tap water. After 5 and 15 minutes, the suspension was poured in the dissolution vessel containing 840 mL of 0.1N HCl dissolution medium. 10 mL of water were used to rinse the container and were added to the dissolution vessel. <tables id="tabl0055" num="0055"><table frame="all"><title>Table 9c</title><tgroup cols="3"><colspec colnum="1" colname="col1" colwidth="18mm" align="center" /><colspec colnum="2" colname="col2" colwidth="59mm" align="center" /><colspec colnum="3" colname="col3" colwidth="60mm" align="center" /><thead valign="middle"><row><entry>Time (h)</entry><entry>% dissolved 5 min reconstitution time</entry><entry>% dissolved 15 min reconstitution time</entry></row></thead><tbody valign="middle"><row><entry>0</entry><entry>0</entry><entry>0</entry></row><row><entry>0,25</entry><entry>48</entry><entry>49</entry></row><row><entry>1</entry><entry>51</entry><entry>51</entry></row><row><entry>3</entry><entry>51</entry><entry>51</entry></row><row><entry>4</entry><entry>51</entry><entry>51</entry></row><row><entry>6</entry><entry>52</entry><entry>51</entry></row><row><entry>8</entry><entry>56</entry><entry>56</entry></row><row><entry>10</entry><entry>71</entry><entry>71</entry></row><row><entry>12</entry><entry>86</entry><entry>85</entry></row><row><entry>16</entry><entry>97</entry><entry>96</entry></row><row><entry>20</entry><entry>99</entry><entry>98</entry></row></tbody></tgroup></table></tables>

EXAMPLE 10. ALTERNATIVE FORMULATIONS

0325Suspending agents are present in the formulation to limit microparticles settling after reconstitution. Without suspending agents, microparticles starts settling as soon as shaking stops. In presence of the suspending agents, full microparticles settling does not occur in less than 1 minute. The following data illustrates the good pourability of the suspension assessed by the high recovery of sodium oxybate content in the dissolution test: IR particles were prepared as follows: 1615.0g of sodium oxybate and 85.0g of water soluble polymer polyvinylpyrrolidone (Povidone - Plasdone^™ K30 from ISP) were solubilized in 1894.3g of absolute ethyl alcohol and 1262.9g of water. The solution was entirely sprayed onto 300g of microcrystalline cellulose spheres (Cellets^™ 127 from Pharmatrans) in a fluid bed spray coater apparatus GPCG1.1. Sodium oxybate IR particles with mean diameter of 271 microns were obtained.

0326MR coated particles were prepared as follows: 39.9g of methacrylic acid copolymer type C (Eudragit^™ L100-55 from Evonik), 80.1g of methacrylic acid copolymer type B (Eudragit^™ S100 from Evonik), 180.0g of hydrogenated cottonseed oil (Lubritab^™ from JRS), were dissolved in 2700.0g of isopropanol at 78°C. The solution was sprayed entirely on 700.0g of sodium oxybate IR particles in a fluid bed spray coater apparatus Glatt^™ G.P.C.G.1.1 with inlet temperature 48°C, spraying rate around 11.5g per min and atomization pressure 1.6 bar. MR coated particles were dried for 2 hours with inlet temperature set to 56°C. MR particles of sodium oxybate with mean diameter of 321 microns were obtained.

0327The finished composition, which contains a 50:50 mixture of MR and IR sodium oxybate particles calculated on their sodium oxybate content, was prepared as follows: 634.0g of the above IR particles, 907.6g of the above MR particles, 25.7g of malic acid (D/L malic acid regular from Bartek), 11.4g of xanthan gum (Xantural^™ 75 from CP Kelco), 17.1g of carragenan gum (Viscarin^™ PH209 from FMC Biopolymer), 17.1g of hydroxyethylcellulose (Natrosol^™ 250M from Ashland ) and 8.1g of magnesium stearate (from Peter Greven) were mixed in a Roue-Roehn mixer. Individual doses of 14.20g (corresponding to a 9g dose with half of the dose as immediate-release fraction and half of the dose as modified release fraction) were weighed.

0328<figref idref="f0016">Figure 32</figref> and Table 10a below depict dissolution profiles of 9g doses determined using a USP apparatus 2 in 0.1N HCl. The dissolution medium was maintained at 37.0 ± 0.5°C and the rotating paddle speed was fixed at 75 rpm. Single dose units were poured in a container containing 50 mL of tap water. After 5 minutes, the suspension was poured in the dissolution vessel containing 840 mL of 0.1N HCl dissolution medium. 10 mL of water were used to rinse the container and were added to the dissolution vessel. Dissolution profile was determined with and without rinsing step. <tables id="tabl0056" num="0056"><table frame="all"><title>Table 10a</title><tgroup cols="3"><colspec colnum="1" colname="col1" colwidth="18mm" align="center" /><colspec colnum="2" colname="col2" colwidth="22mm" align="center" /><colspec colnum="3" colname="col3" colwidth="27mm" align="center" /><thead valign="middle"><row><entry>Time (h)</entry><entry>with rinsing</entry><entry>without rinsing</entry></row></thead><tbody valign="middle"><row><entry>0</entry><entry>0</entry><entry>0</entry></row><row><entry>0,25</entry><entry>47</entry><entry>46</entry></row><row><entry>1</entry><entry>51</entry><entry>51</entry></row><row><entry>3</entry><entry>53</entry><entry>52</entry></row><row><entry>6,0</entry><entry>54</entry><entry>53</entry></row><row><entry>8</entry><entry>61</entry><entry>60</entry></row><row><entry>10</entry><entry>77</entry><entry>74</entry></row><row><entry>12</entry><entry>91</entry><entry>88</entry></row><row><entry>16</entry><entry>98</entry><entry>95</entry></row><row><entry>20</entry><entry>98</entry><entry>96</entry></row></tbody></tgroup></table></tables>

EXAMPLE 11. ALTERNATIVE FORMULATIONS WITH A DIFFERENT RATIO OF IR AND MR FRACTIONS

0329Different prototypes were prepared and evaluated to determine the effect of IR/MR ratio.

Example 11a -- 15% IR / 85% IR with MR pH*6.5 microparticles

0330IR particles were prepared as follows: 1615.0g of Sodium Oxybate and 85.0g of water soluble polymer polyvinylpyrrolidone (Povidone - Plasdone^™ K30 from ISP) were solubilized in 1896.2g of absolute ethyl alcohol and 1264.4g of water. The solution was entirely sprayed onto 300g of microcrystalline cellulose spheres (Cellets^™ 127 from Pharmatrans) in a fluid bed spray coater apparatus GPCG1.1. Sodium oxybate IR particles with mean diameter of 275 microns were obtained.

0331MR coated particles were prepared as follows: 22.8g of Methacrylic acid copolymer Type C (Eudragit^™ L100-55 from Evonik), 45.8g of Methacrylic acid copolymer Type B (Eudragit^™ S100 from Evonik), 102.9g of Hydrogenated cottonseed oil (Lubritab^™ from JRS), were dissolved in 1543.1g of isopropanol at 78°C. The solution was sprayed entirely on 400.0g of IR particles in a fluid bed spray coater apparatus Glatt^™ G.P.C.G.1.1 with inlet temperature 47°C, spraying rate around 10.8g per min and atomization pressure 1.3 bar. MR microparticles were dried for 2 hours with inlet temperature set to 56°C. Sodium oxybate MR coated particles with mean diameter of 330 microns were obtained.

033217.1 g of MR microparticles were mixed with 0.09g of magnesium stearate (from Peter Greven). The dissolution profile of 4000mg of the mixture which correspond to 2250mg of sodium oxybate per vessel was determined in 900ml of 0.1N HCl and pH 6.8 phosphate buffer (0.05M monobasic potassium phosphate solution - pH adjusted to 6.8 with 5N NaOH) using the USP apparatus 2. Dissolution medium temperature was maintained at 37.0 ± 0.5 °C, and the rotating paddle speed was set at 75 rpm. The release profiles are shown in <figref idref="f0017">Figure 33</figref>, Table 11a, and Table 11b. <tables id="tabl0057" num="0057"><table frame="all"><title>Table 11a.Dissolution data - 0.1N HCl</title><tgroup cols="2"><colspec colnum="1" colname="col1" colwidth="26mm" align="center" /><colspec colnum="2" colname="col2" colwidth="27mm" align="center" /><thead valign="middle"><row><entry>Time (hour)</entry><entry>% dissolved</entry></row></thead><tbody valign="middle"><row><entry>0</entry><entry>0,0</entry></row><row><entry>0,25</entry><entry>1</entry></row><row><entry>1</entry><entry>1</entry></row><row><entry>3</entry><entry>2</entry></row><row><entry>4</entry><entry>3</entry></row><row><entry>6</entry><entry>6</entry></row><row><entry>8</entry><entry>24</entry></row><row><entry>10</entry><entry>59</entry></row><row><entry>12</entry><entry>83</entry></row><row><entry>16</entry><entry>95</entry></row><row><entry>20</entry><entry>97</entry></row></tbody></tgroup></table></tables><tables id="tabl0058" num="0058"><table frame="all"><title>Table 11b. Dissolution data - 50mM phosphate buffer pH 6.8</title><tgroup cols="2"><colspec colnum="1" colname="col1" colwidth="42mm" align="center" /><colspec colnum="2" colname="col2" colwidth="43mm" align="center" /><thead valign="middle"><row><entry>Time (hour)</entry><entry>% dissolved</entry></row></thead><tbody valign="middle"><row><entry>0</entry><entry>0</entry></row><row><entry>0,25</entry><entry>18</entry></row><row><entry>0,5</entry><entry>80</entry></row><row><entry>0,75</entry><entry>97</entry></row><row><entry>1</entry><entry>97</entry></row><row><entry>2</entry><entry>97</entry></row></tbody></tgroup></table></tables>

0333The qualitative composition of 4.5g dose units comprising 15% of the dose as IR fraction and 85% of the dose as MR fraction is described in Table 11c. <tables id="tabl0059" num="0059"><table frame="all"><title>Table 11c</title><tgroup cols="3"><colspec colnum="1" colname="col1" colwidth="37mm" /><colspec colnum="2" colname="col2" colwidth="70mm" /><colspec colnum="3" colname="col3" colwidth="44mm" align="center" /><thead valign="middle"><row><entry align="center">Component</entry><entry align="center">Function</entry><entry>Quantity per 4.5 g dose (g)</entry></row></thead><tbody><row><entry>MR microparticles</entry><entry>Modified release fraction of sodium oxybate</entry><entry>6.767</entry></row><row valign="middle"><entry>IR microparticles</entry><entry>Immediate release fraction of sodium oxybate</entry><entry>0.836</entry></row><row valign="middle"><entry>Malic acid</entry><entry>Acidifying agent</entry><entry>0.034</entry></row><row valign="middle"><entry>Xanthan gum</entry><entry>Suspending agent</entry><entry>0.050</entry></row><row valign="middle"><entry>Hydroxyethylcellulose</entry><entry>Suspending agent</entry><entry>0.075</entry></row><row valign="middle"><entry>Carrageenan gum</entry><entry>Suspending agent</entry><entry>0.075</entry></row><row><entry valign="bottom">Magnesium stearate</entry><entry>Lubricant</entry><entry>0.039</entry></row><row valign="middle"><entry>Total</entry><entry /><entry>7.876</entry></row></tbody></tgroup></table></tables>

0334The finished composition, which contains a 85:15 mixture of MR and IR particles calculated on their sodium oxybate content, can be prepared as follows: 100.0g of the above IR particles, 809.5g of the above MR particles, 4.0g of malic acid (D/L malic acid regular from Bartek), 6.0g of xanthan gum (Xantural^™ 75 from CP Kelco), 9.0g of carragenan gum (Viscarin^™ PH209 from FMC Biopolymer), 9.0g of hydroxyethylcellulose (Natrosol^™ 250M from Ashland ) and 4.7g of magnesium stearate (from Peter Greven) were mixed in a Roue-Roehn mixer. Individual doses of 7.88g (corresponding to a 4.5g dose with 15% of the dose as immediate-release fraction and 85% of the dose as modified release fraction) were weighed.

0335After reconstitution with 50 ml of tap water and a rinsing volume of 10 ml of tap water, the finished composition will display the dissolution profiles in <figref idref="f0017">Figures 34</figref> and <figref idref="f0018">35</figref> and Tables 11d and 11e in 840 ml of 0.1N HCl and in pH6.8 phosphate buffer (0.05M monobasic potassium phosphate solution - pH adjusted to 6.8 with 5N NaOH) using a USP apparatus 2, at 37.0 ± 0.5°C and the rotating paddle speed at 75 rpm. <tables id="tabl0060" num="0060"><table frame="all"><title>Table 11d</title><tgroup cols="2"><colspec colnum="1" colname="col1" colwidth="23mm" align="center" /><colspec colnum="2" colname="col2" colwidth="23mm" align="center" /><thead valign="middle"><row><entry>Time (hour)</entry><entry>% dissolved</entry></row></thead><tbody valign="middle"><row><entry>0</entry><entry>0,0</entry></row><row><entry>0,25</entry><entry>16</entry></row><row><entry>1</entry><entry>16</entry></row><row><entry>3</entry><entry>17</entry></row><row><entry>4</entry><entry>17</entry></row><row><entry>6</entry><entry>20</entry></row><row><entry>8</entry><entry>35</entry></row><row><entry>10</entry><entry>65</entry></row><row><entry>12</entry><entry>85</entry></row><row><entry>16</entry><entry>96</entry></row></tbody></tgroup></table></tables><tables id="tabl0061" num="0061"><table frame="all"><title>Table 11e</title><tgroup cols="2"><colspec colnum="1" colname="col1" colwidth="22mm" /><colspec colnum="2" colname="col2" colwidth="23mm" /><thead valign="top"><row><entry>Time (hour)</entry><entry>% dissolved</entry></row></thead><tbody><row><entry>0</entry><entry>0</entry></row><row><entry>0,25</entry><entry>30</entry></row><row><entry>0,5</entry><entry>83</entry></row><row><entry>0,75</entry><entry>97</entry></row><row><entry>1</entry><entry>98</entry></row><row><entry>2</entry><entry>98</entry></row></tbody></tgroup></table></tables>

Example 11b -- 30% IR /70% MR with MR pH*6.2 microparticles

0336IR particles were prepared as follows: 1615.1g of sodium oxybate and 85.0g of water soluble polymer polyvinylpyrrolidone (Povidone - Plasdone^™ K30 from ISP) were solubilized in 1903.2g of absolute ethyl alcohol and 1267.1g of water. The solution was entirely sprayed onto 300g of microcrystalline cellulose spheres (Cellets^™ 127 from Pharmatrans) in a fluid bed spray coater apparatus GPCG1.1. Sodium oxybate IR particles with mean diameter of 268 microns were obtained.

0337MR coated particles were prepared as follows: 36.6g of Methacrylic acid copolymer Type C (Eudragit^™ L100-55 from Evonik), 32.1g of methacrylic acid copolymer type B (Eudragit^™ S100 from Evonik), 103.0g of hydrogenated cottonseed oil (Lubritab^™ from JRS), were dissolved in 1543.5g of isopropanol at 78°C. The solution was sprayed entirely on 400.0g of IR particles in a fluid bed spray coater apparatus Glatt^™ G.P.C.G.1.1 with inlet temperature 48°C, spraying rate around 12.0g per min and atomization pressure 1.3 bar. MR particles were dried for 2 hours with inlet temperature set to 56°C. Sodium oxybate MR coated particles with mean diameter of 323 microns were obtained.

033817.0 g of sodium oxybate MR particles were mixed with 0.09g of magnesium stearate (from Peter Greven). The dissolution profile of 4050mg of the mixture which correspond to 2280mg of sodium oxybate per vessel was determined in 900ml of 0.1N HCl dissolution medium using the USP apparatus 2. Dissolution medium temperature was maintained at 37.0 ± 0.5 °C, and the rotating paddle speed was set at 75 rpm. The release profile in 0.1N HCl is shown in <figref idref="f0018">Figure 36</figref> and Table 11f. <tables id="tabl0062" num="0062"><table frame="all"><title>Table 11f</title><tgroup cols="2"><colspec colnum="1" colname="col1" colwidth="23mm" align="center" /><colspec colnum="2" colname="col2" colwidth="23mm" align="center" /><thead valign="middle"><row><entry>Time (hour)</entry><entry>% dissolved</entry></row></thead><tbody valign="middle"><row><entry>0,0</entry><entry>0</entry></row><row><entry>0,3</entry><entry>1</entry></row><row><entry>1,0</entry><entry>3</entry></row><row><entry>3,0</entry><entry>4</entry></row><row><entry>4,0</entry><entry>4</entry></row><row><entry>6,0</entry><entry>8</entry></row><row><entry>8,0</entry><entry>40</entry></row><row><entry>10,0</entry><entry>81</entry></row><row><entry>12,0</entry><entry>95</entry></row><row><entry>16,0</entry><entry>100</entry></row><row><entry>20,0</entry><entry>99</entry></row></tbody></tgroup></table></tables>

0339The finished composition, which contains a 70:30 mixture of MR and IR sodium oxybate particles calculated on their sodium oxybate content, was prepared as follows: 92.1g of the above IR particles, 306.5g of the above MR particles, 7.5g of malic acid (D/L malic acid regular from Bartek), 2.8g of xanthan gum (Xantural^™ 75 from CP Kelco), 4.1g of carragenan gum (Viscarin^™ PH209 from FMC Biopolymer), 4.1g of hydroxyethylcellulose (Natrosol^™ 250M from Ashland ) and 2.0g of magnesium stearate (from Peter Greven) were mixed in a Roue-Roehn mixer. Individual doses of 7.62g (corresponding to a 4.5g dose with 30% of the dose as immediate-release fraction and 70% of the dose as modified release fraction) were weighed.

0340<figref idref="f0019">Figures 37 and 38</figref> and Tables 11g and 11h below depict dissolution profiles determined using a USP apparatus 2 in 0.1N HCl and pH 6.8 phosphate buffer (0.05M monobasic potassium phosphate solution - pH adjusted to 6.8 with 5N NaOH). The dissolution medium was maintained at 37.0 ± 0.5°C and the rotating paddle speed was fixed at 75 rpm. Single dose units were poured in a container containing 50 mL of tap water. After 5 minutes, the suspension was poured in the dissolution vessel containing 840 mL of dissolution medium. 10 mL of water were used to rinse the container and were added to the dissolution vessel. <tables id="tabl0063" num="0063"><table frame="all"><title>Table 11g</title><tgroup cols="2"><colspec colnum="1" colname="col1" colwidth="23mm" align="center" /><colspec colnum="2" colname="col2" colwidth="41mm" align="center" /><thead valign="middle"><row><entry>Time (hour)</entry><entry>% dissolved in 0.1N HCl</entry></row></thead><tbody valign="middle"><row><entry>0,0</entry><entry>0,0</entry></row><row><entry>0,3</entry><entry>29</entry></row><row><entry>1,0</entry><entry>31</entry></row><row><entry>3,0</entry><entry>32</entry></row><row><entry>4,0</entry><entry>32</entry></row><row><entry>6,0</entry><entry>35</entry></row><row><entry>8,0</entry><entry>70</entry></row><row><entry>10,0</entry><entry>94</entry></row><row><entry>12,0</entry><entry>99</entry></row><row><entry>16,0</entry><entry>99</entry></row></tbody></tgroup></table></tables><tables id="tabl0064" num="0064"><table frame="all"><title>Table 11h</title><tgroup cols="2"><colspec colnum="1" colname="col1" colwidth="18mm" align="center" /><colspec colnum="2" colname="col2" colwidth="62mm" align="center" /><thead valign="middle"><row><entry>Time (h)</entry><entry>% dissolved in pH 6.8 phosphate buffer</entry></row></thead><tbody valign="middle"><row><entry>0</entry><entry>0</entry></row><row><entry>0,25</entry><entry>64</entry></row><row><entry>0,5</entry><entry>87</entry></row><row><entry>1</entry><entry>100</entry></row><row><entry>2</entry><entry>100</entry></row><row><entry>3</entry><entry>102</entry></row></tbody></tgroup></table></tables>

Example 11c -- 65% IR /35% MR with MR pH*6.5 microparticles

0341IR particles were prepared as follows: 1615.0g of sodium oxybate and 85.0g of water soluble polymer polyvinylpyrrolidone (Povidone - Plasdone^™ K30 from ISP) were solubilized in 1894.3g of absolute ethyl alcohol and 1262.9g of water. The solution was entirely sprayed onto 300g of microcrystalline cellulose spheres (Cellets^™ 127 from Pharmatrans) in a fluid bed spray coater apparatus GPCG1.1. Sodium oxybate IR particles with mean diameter of 270 microns were obtained.

0342MR coated particles were prepared as follows: 22.8g of methacrylic acid copolymer type C (Eudragit^™ L100-55 from Evonik), 45.8g of methacrylic acid copolymer type B (Eudragit^™ S100 from Evonik), 102.9g of hydrogenated cottonseed oil (Lubritab^™ from JRS), were dissolved in 1543.1g of isopropanol at 78°C. The solution was sprayed entirely on 400.0g of IR particles in a fluid bed spray coater apparatus Glatt^™ G.P.C.G.1.1 with inlet temperature 47°C, spraying rate around 10.8g per min and atomization pressure 1.3 bar. MR coated particles were dried for 2 hours with inlet temperature set to 56°C. Sodium oxybate MR coated particles with mean diameter of 330 microns were obtained.

0343Refer to the Example 11a for the dissolution profile of the MR microparticles. The qualitative composition of 4.5g dose units comprising 65% of the dose as IR fraction and 35% of the dose as MR fraction is described in Table 11i. <tables id="tabl0065" num="0065"><table frame="all"><title>Table 11i</title><tgroup cols="3"><colspec colnum="1" colname="col1" colwidth="37mm" /><colspec colnum="2" colname="col2" colwidth="70mm" /><colspec colnum="3" colname="col3" colwidth="44mm" align="center" /><thead valign="top"><row><entry align="center">Component</entry><entry align="center">Function</entry><entry>Quantity per 4.5 g dose (g)</entry></row></thead><tbody><row valign="middle"><entry>MR microparticles</entry><entry>Modified release fraction of sodium oxybate</entry><entry>2.786</entry></row><row valign="middle"><entry>IR microparticles</entry><entry>Immediate release fraction of sodium oxybate</entry><entry>3.622</entry></row><row valign="middle"><entry>Malic acid</entry><entry>Acidifying agent</entry><entry>0.110</entry></row><row valign="middle"><entry>Xanthan gum</entry><entry>Suspending agent</entry><entry>0.050</entry></row><row valign="middle"><entry>Hydroxyethylcellulose</entry><entry>Suspending agent</entry><entry>0.075</entry></row><row valign="middle"><entry>Carrageenan gum</entry><entry>Suspending agent</entry><entry>0.075</entry></row><row><entry valign="bottom">Magnesium stearate</entry><entry>Lubricant</entry><entry>0.034</entry></row><row valign="middle"><entry>Total</entry><entry /><entry>6.752</entry></row></tbody></tgroup></table></tables>

0344The finished composition, which contains a 85:15 mixture of sodium oxybate MR and IR particles calculated on their sodium oxybate content, can be prepared as follows: 100.0g of the above IR particles, 76.9g of the above MR coated particles, 3.0g of Malic acid (D/L malic acid regular from Bartek), 1.4g of xanthan gum (Xantural^™ 75 from CP Kelco), 2.1g of carragenan gum (Viscarin^™ PH209 from FMC Biopolymer), 2.1g of hydroxyethylcellulose (Natrosol^™ 250M from Ashland ) and 0.9g of magnesium stearate (from Peter Greven) were mixed in a Roue-Roehn mixer. Individual doses of 6.75g (corresponding to a 4.5g dose with 65% of the dose as immediate-release fraction and 35% of the dose as modified release fraction) were weighed.

0345Dissolution profile: After reconstitution with 50 ml tap water and rinsing with 10 ml of tap water, the finished composition will display the dissolution profiles in <figref idref="f0020">Figures 39 and 40</figref> and Tables 11j and 11k in 840ml of 0.1N HCl and in pH 6.8 phosphate buffer (0.05M monobasic potassium phosphate solution - pH adjusted to 6.8 with 5N NaOH) using a USP apparatus 2, at 37.0 ± 0.5°C and the rotating paddle speed at 75 rpm. <tables id="tabl0066" num="0066"><table frame="all"><title>Table 11j</title><tgroup cols="2"><colspec colnum="1" colname="col1" colwidth="23mm" align="center" /><colspec colnum="2" colname="col2" colwidth="41mm" align="center" /><thead valign="top"><row><entry>Time (hour)</entry><entry>% dissolved in 0.1N HCl</entry></row></thead><tbody><row><entry>0</entry><entry>0,0</entry></row><row><entry>0,25</entry><entry>65</entry></row><row><entry>1</entry><entry>65</entry></row><row><entry>3</entry><entry>66</entry></row><row><entry>4</entry><entry>66</entry></row><row><entry>6</entry><entry>67</entry></row><row><entry>8</entry><entry>73</entry></row><row><entry>10</entry><entry>86</entry></row><row><entry>12</entry><entry>94</entry></row><row><entry>16</entry><entry>98</entry></row><row><entry>20</entry><entry>99</entry></row></tbody></tgroup></table></tables><tables id="tabl0067" num="0067"><table frame="all"><title>Table 11k</title><tgroup cols="2"><colspec colnum="1" colname="col1" colwidth="23mm" align="center" /><colspec colnum="2" colname="col2" colwidth="62mm" align="center" /><thead valign="top"><row><entry>Time (hour)</entry><entry>% dissolved in pH 6.8 phosphate buffer</entry></row></thead><tbody><row><entry>0</entry><entry>0</entry></row><row><entry>0,25</entry><entry>71</entry></row><row><entry>0,5</entry><entry>93</entry></row><row><entry>0,75</entry><entry>99</entry></row><row><entry>1</entry><entry>99</entry></row><row><entry>2</entry><entry>99</entry></row></tbody></tgroup></table></tables>

EXAMPLE 12. ALTERNATIVE FORMULATIONS WITH IR FRACTION OBTAINED USING DIFFERENT MANUFACTURING PROCESSES.

0346Prototype formulations were developed to test the impact of different manufacturing processes on the dissolution of the formulations.

Example 12a - IR portion = raw sodium oxybate

0347IR particles to serve as cores of the MR coated microparticles were prepared as follows: 1615.0g of sodium oxybate and 85.0g of water soluble polymer polyvinylpyrrolidone (Povidone - Plasdone^™ K30 from ISP) were solubilized in 1894.3g of absolute ethyl alcohol and 1262.9g of water. The solution was entirely sprayed onto 300g of microcrystalline cellulose spheres (Cellets^™ 127 from Pharmatrans) in a fluid bed spray coater apparatus GPCG1.1. Sodium oxybate IR particles with mean diameter of 256 microns were obtained.

0348MR coated particles were prepared as follows: 22.8g of methacrylic acid copolymer type C (Eudragit^™ L100-55 from Evonik), 45.8g of methacrylic acid copolymer type B (Eudragit^™ S100 from Evonik), 102.9g of hydrogenated cottonseed oil (Lubritab^™ from JRS), were dissolved in 1542.9g of isopropanol at 78°C. The solution was sprayed entirely on 400.0g of IR particles in a fluid bed spray coater apparatus Glatt^™ G.P.C.G.1.1 with inlet temperature 48°C, spraying rate around 10g per min and atomization pressure 1.3 bar. MR particles were dried for 2 hours with inlet temperature set to 56°C. Sodium oxybate MR coated particles with mean diameter of 308 microns were obtained.

034925.2 g of MR microparticles were mixed with 0.26g of magnesium stearate (from Peter Greven) and 0.13g of colloidal silicon dioxide (Aerosil^™ 200 from Evonik). The dissolution profile of 4000mg of the mixture which correspond to 2250mg of sodium oxybate per vessel was determined in 900ml of 0.1N HCl dissolution medium using the USP apparatus 2. Dissolution medium temperature was maintained at 37.0 ± 0.5 °C, and the rotating paddle speed was set at 75 rpm. The release profile in 0.1N HCl is shown in <figref idref="f0021">Figure 41</figref> and Table 12a. <tables id="tabl0068" num="0068"><table frame="all"><title>Table 12a</title><tgroup cols="2"><colspec colnum="1" colname="col1" colwidth="23mm" align="center" /><colspec colnum="2" colname="col2" colwidth="23mm" align="center" /><thead valign="top"><row><entry>Time (hour)</entry><entry>% dissolved</entry></row></thead><tbody><row><entry>0</entry><entry>0</entry></row><row><entry>0,25</entry><entry>1</entry></row><row><entry>1</entry><entry>1</entry></row><row><entry>3</entry><entry>2</entry></row><row><entry>4</entry><entry>3</entry></row><row><entry>6</entry><entry>14</entry></row><row><entry>8</entry><entry>40</entry></row><row><entry>10</entry><entry>65</entry></row><row><entry>12</entry><entry>78</entry></row><row><entry>16</entry><entry>89</entry></row></tbody></tgroup></table></tables>

0350The finished composition, which contains a 50:50 mixture of sodium oxybate MR coated particles and raw sodium oxybate as IR fraction calculated on their sodium oxybate content, was prepared as follows: 36g of raw sodium oxybate, 63.7g of the above MR coated particles, 1.8g of malic acid (D/L malic acid regular from Bartek), 1.6g of xanthan gum (Xantural^™ 75 from CP Kelco), 2.4g of carragenan gum (Viscarin^™ PH209 from FMC Biopolymer), 0.047g of an apple aroma and 0.3g of hydrophilic fumed silica (Aerosil 200 from Degussa) were mixed in a Roue-Roehn mixer. Individual doses of 6.66g (corresponding to a 4.5g dose with half of the dose as raw sodium oxybate as IR fraction and half of the dose as modified release fraction) were weighed.

0351<figref idref="f0021">Figure 42</figref> and Table 12b below depict dissolution profiles determined using a USP apparatus 2 in 0.1N HCl. The dissolution medium was maintained at 37.0 ± 0.5°C and the rotating paddle speed was fixed at 75 rpm. Single dose units were poured in a container containing 50 mL of tap water. After 5 minutes, the suspension was poured in the dissolution vessel containing 840 mL of 0.1N HCl dissolution medium. 10 mL of water were used to rinse the container and were added to the dissolution vessel. <tables id="tabl0069" num="0069"><table frame="all"><title>Table 12b</title><tgroup cols="2"><colspec colnum="1" colname="col1" colwidth="23mm" align="center" /><colspec colnum="2" colname="col2" colwidth="23mm" align="center" /><thead valign="top"><row><entry>Time (hour)</entry><entry>% dissolved</entry></row></thead><tbody><row><entry>0</entry><entry>0</entry></row><row><entry>0,25</entry><entry>50</entry></row><row><entry>1</entry><entry>52</entry></row><row><entry>4</entry><entry>55</entry></row><row><entry>6</entry><entry>57</entry></row><row><entry>8</entry><entry>70</entry></row><row><entry>10</entry><entry>82</entry></row><row><entry>12</entry><entry>87</entry></row><row><entry>16</entry><entry>93</entry></row></tbody></tgroup></table></tables>

0352Considering that the 0.1N HCl dissolution profile of the MR coated particles is similar to the MR microparticles from examples 1 and 1bis, the dissolution profile in pH 6.8 phosphate buffer of the finished composition is expected to be similar to the profile depicted in <figref idref="f0004">Figure 8</figref>, insofar as the MR particles are similar and only the nature of the immediate-release fraction was changed.

Example 12b -- IR = microparticles obtained by Extrusion-spheronization

0353IR particles were prepared as follows: 97g of sodium oxybate and 3g of water soluble polymer polyvinylpyrrolidone (Povidone - Plasdone^™ K30 from ISP) were mixed with 7.5g of water. The mixture was extruded through a 400 micron mesh and spheronized at 1500rpm for 1.5min in an extruder-spheronizer Fuji-Paudal MG-55. After drying for 4 hours at 45°C in a ventilated oven, microparticles were sieved between 150 microns and 500 microns.

0354MR coated particles were prepared as described in Example 14.

0355The finished composition, which contains a 50:50 mixture of MR and IR sodium oxybate particles calculated on their sodium oxybate content, was prepared as follows: 67.4g of the above IR particles obtained by extrusion-spheronization, 115.6g of the above MR coated particles, 3.3g of malic acid (D/L malic acid regular from Bartek), 0.9g of xanthan gum (Xantural^™ 75 from CP Kelco), 0.9g of hydrophilic fumed silica (Aerosil 200 from Degussa) and 1.9g of magnesium stearate (from Peter Greven) were mixed in a Roue-Roehn mixer. Individual doses of 6.54g (corresponding to a 4.5g dose with half of the dose as immediate-release fraction and half of the dose as modified release fraction) were weighed.

0356<figref idref="f0022">Figure 43</figref> and Table 12c below depict dissolution profiles determined using a USP apparatus 2 in 0.1N HCl. The dissolution medium was maintained at 37.0 ± 0.5°C and the rotating paddle speed was fixed at 75 rpm. Single dose units were poured in a container containing 50 mL of tap water. After 5 minutes, the suspension was poured in the dissolution vessel containing 840 mL of 0.1N HCl dissolution medium. 10 mL of water were used to rinse the container and were added to the dissolution vessel. <tables id="tabl0070" num="0070"><table frame="all"><title>Table 12c</title><tgroup cols="2"><colspec colnum="1" colname="col1" colwidth="22mm" /><colspec colnum="2" colname="col2" colwidth="40mm" /><thead valign="top"><row><entry>Time (hour)</entry><entry>% dissolved in 0.1N HCl</entry></row></thead><tbody><row><entry>0</entry><entry>0</entry></row><row><entry>0,25</entry><entry>51</entry></row><row><entry>1</entry><entry>53</entry></row><row><entry>4</entry><entry>54</entry></row><row><entry>6</entry><entry>54</entry></row><row><entry>8</entry><entry>56</entry></row><row><entry>10</entry><entry>65</entry></row><row><entry>12</entry><entry>79</entry></row><row><entry>16</entry><entry>92</entry></row></tbody></tgroup></table></tables>

0357Based on the dissolution profile of the MR coated particles in pH 6.8 phosphate buffer, finished compositions are expected to have the dissolution profile in pH 6.8 phosphate buffer given in Table 12d and <figref idref="f0022">Figure 44</figref>. <tables id="tabl0071" num="0071"><table frame="all"><title>Table 12d</title><tgroup cols="2"><colspec colnum="1" colname="col1" colwidth="18mm" align="center" /><colspec colnum="2" colname="col2" colwidth="62mm" align="center" /><thead valign="top"><row><entry>Time (h)</entry><entry>% dissolved in pH 6.8 phosphate buffer</entry></row></thead><tbody><row><entry>0</entry><entry>0</entry></row><row><entry>0,25</entry><entry>55</entry></row><row><entry>0,50</entry><entry>97</entry></row><row><entry>1</entry><entry>101</entry></row><row><entry>1,5</entry><entry>102</entry></row><row><entry>2</entry><entry>101</entry></row><row><entry>3</entry><entry>101</entry></row></tbody></tgroup></table></tables>

EXAMPLE 13. ALTERNATIVE FORMULATION WITHOUT BINDER.

0358IR particles were prepared as follows: 1700.0g of Sodium Oxybate are solubilized in 1899.4g of absolute ethyl alcohol and 1261.3g of water. The solution is entirely sprayed onto 300g of microcrystalline cellulose spheres (Cellets 127 from Pharmatrans) in a fluid bed spray coater apparatus GPCG1.1. Sodium oxybate IR particles with mean diameter of 244 microns are obtained.

0359MR coated particles were prepared as follows: 17.1g of methacrylic acid copolymer type C (Eudragit L100-55 from Evonik), 34.3g of methacrylic acid copolymer type B (Eudragit S100 from Evonik), 77.1g of hydrogenated cottonseed oil (Lubritab from JRS), are dissolved in 1157.9g of isopropanol at 78°C. The solution is sprayed entirely on 300.0g of IR particles prepared above in a fluid bed spray coater apparatus Glatt G.P.C.G.1.1 with inlet temperature 48°C, spraying rate around 10.7g per min and atomization pressure 1.3 bar. MR microparticles were dried for 2 hours with inlet temperature set to 56°C. Sodium oxybate MR coated particles with mean diameter of 289 microns are obtained.

036025.3 g of MR coated microparticles were mixed with 0.12g of magnesium stearate (from Peter Greven). The dissolution profile of 4000mg of the mixture which correspond to 2368mg of sodium oxybate per vessel was determined in 900ml of 0.1N HCl and pH 6.8 phosphate buffer (0.05M monobasic potassium phosphate solution with pH adjusted to 6.8 with 5N NaOH) using the USP apparatus 2. Dissolution medium temperature was maintained at 37.0 ± 0.5 °C, and the rotating paddle speed was set at 75 rpm. The release profiles are shown below in <figref idref="f0023">Figure 45</figref> and Tables 13a and 13b. <tables id="tabl0072" num="0072"><table frame="all"><title>Table 13a.Dissolution data - 0.1N HCl</title><tgroup cols="2"><colspec colnum="1" colname="col1" colwidth="24mm" align="center" /><colspec colnum="2" colname="col2" colwidth="29mm" align="center" /><thead valign="top"><row><entry>Time (h)</entry><entry>% dissolved</entry></row></thead><tbody><row><entry>0</entry><entry>0</entry></row><row><entry>0,25</entry><entry>0</entry></row><row><entry>1</entry><entry>0</entry></row><row><entry>3</entry><entry>1</entry></row><row><entry>4</entry><entry>3</entry></row><row><entry>6</entry><entry>29</entry></row><row><entry>8</entry><entry>50</entry></row><row><entry>10</entry><entry>69</entry></row><row><entry>12</entry><entry>82</entry></row><row><entry>16</entry><entry>97</entry></row><row><entry>20</entry><entry>102</entry></row></tbody></tgroup></table></tables><tables id="tabl0073" num="0073"><table frame="all"><title>Table 13b. Dissolution data - 50mM pH 6.8 phosphate buffer</title><tgroup cols="2"><colspec colnum="1" colname="col1" colwidth="40mm" align="center" /><colspec colnum="2" colname="col2" colwidth="45mm" align="center" /><thead valign="top"><row><entry>Time (h)</entry><entry>% dissolved</entry></row></thead><tbody><row><entry>0</entry><entry>0</entry></row><row><entry>0,25</entry><entry>5</entry></row><row><entry>1</entry><entry>102</entry></row><row><entry>3</entry><entry>106</entry></row></tbody></tgroup></table></tables>

0361The qualitative composition of 4.5g dose units comprising 50% of the dose as IR fraction and 50% of the dose as MR fraction is described in Table 13c. <tables id="tabl0074" num="0074"><table frame="all"><title>Table 13c</title><tgroup cols="3"><colspec colnum="1" colname="col1" colwidth="37mm" /><colspec colnum="2" colname="col2" colwidth="70mm" /><colspec colnum="3" colname="col3" colwidth="44mm" align="center" /><thead valign="top"><row><entry align="center">Component</entry><entry align="center">Function</entry><entry>Quantity per 4.5 g dose (g)</entry></row></thead><tbody><row valign="middle"><entry>MR microparticles</entry><entry>Modified release fraction of sodium oxybate</entry><entry>3.841</entry></row><row valign="middle"><entry>IR microparticles</entry><entry>Immediate release fraction of sodium oxybate</entry><entry>2.647</entry></row><row valign="middle"><entry>Malic acid</entry><entry>Acidifying agent</entry><entry>0.113</entry></row><row valign="middle"><entry>Xanthan gum</entry><entry>Suspending agent</entry><entry>0.050</entry></row><row valign="middle"><entry>Hydroxyethylcellulose</entry><entry>Suspending agent</entry><entry>0.075</entry></row><row valign="middle"><entry>Carrageenan gum</entry><entry>Suspending agent</entry><entry>0.075</entry></row><row><entry valign="bottom">Magnesium stearate</entry><entry>Lubricant</entry><entry>0.034</entry></row><row valign="middle"><entry>Total</entry><entry /><entry>6.835</entry></row></tbody></tgroup></table></tables>

0362After reconstitution with 50ml of tap water and rinsing with 10ml of tap water, the finished composition is expected to provide the following dissolution profiles in <figref idref="f0023">Figures 46</figref> and <figref idref="f0024">47</figref> and Tables 13d and 13e in 840ml of 0.1N HCl and pH6.8 phosphate buffer (0.05M monobasic potassium phosphate solution with pH adjusted to 6.8 with 5N NaOH) using a USP apparatus 2, at 37.0 ± 0.5°C and the rotating paddle speed at 75 rpm. <tables id="tabl0075" num="0075"><table frame="all"><title>Table 13d</title><tgroup cols="2"><colspec colnum="1" colname="col1" colwidth="18mm" align="center" /><colspec colnum="2" colname="col2" colwidth="41mm" align="center" /><thead valign="top"><row><entry>Time (h)</entry><entry>% dissolved in 0.1N HCl</entry></row></thead><tbody><row><entry>0,0</entry><entry>0</entry></row><row><entry>0,3</entry><entry>50</entry></row><row><entry>1,0</entry><entry>50</entry></row><row><entry>3,0</entry><entry>50</entry></row><row><entry>4,0</entry><entry>52</entry></row><row><entry>6,0</entry><entry>64</entry></row><row><entry>8,0</entry><entry>75</entry></row><row><entry>10,0</entry><entry>84</entry></row><row><entry>12,0</entry><entry>91</entry></row><row><entry>16,0</entry><entry>98</entry></row><row><entry>20,0</entry><entry>101</entry></row></tbody></tgroup></table></tables><tables id="tabl0076" num="0076"><table frame="all"><title>Table 13e</title><tgroup cols="2"><colspec colnum="1" colname="col1" colwidth="18mm" align="center" /><colspec colnum="2" colname="col2" colwidth="46mm" align="center" /><thead valign="top"><row><entry>Time (h)</entry><entry>% dissolved in pH 6.8 buffer</entry></row></thead><tbody><row><entry>0</entry><entry>0</entry></row><row><entry>0,25</entry><entry>53</entry></row><row><entry>1,0</entry><entry>101</entry></row><row><entry>3</entry><entry>103</entry></row></tbody></tgroup></table></tables>

EXAMPLE 14. MR PARTICLES WITH LARGER CORE SIZE (160 MICRONS).

0363Different prototypes were also developed to evaluate the impact of the core size on the dissolution of the formulation.

0364IR particles were prepared as follows: 1615.0g of sodium oxybate and 85.0g of water soluble polymer polyvinylpyrrolidone (Povidone - Plasdone^™ K30 from ISP) were solubilized in 1894.3g of absolute ethyl alcohol and 1262.9g of water. The solution was entirely sprayed onto 300g of microcrystalline cellulose spheres (Cellets^™ 100 from Pharmatrans) (D[4,3]=160 microns) in a fluid bed spray coater apparatus GPCG1.1. Sodium oxybate IR particles with mean diameter of 310 microns were obtained.

0365MR coated particles were prepared as follows: 25.7g of methacrylic acid copolymer type C (Eudragit^™ L100-55 from Evonik), 51.5g of methacrylic acid copolymer type B (Eudragit^™ S100 from Evonik), 115.7g of hydrogenated cottonseed oil (Lubritab^™ from JRS), were dissolved in 1735.7g of isopropanol at 78°C. The solution was sprayed entirely on 450.0g of IR particles in a fluid bed spray coater apparatus Glatt^™ G.P.C.G.1.1 with inlet temperature 47°C, spraying rate around 9.6g per min and atomization pressure 1.6 bar. MR particles were dried for 2 hours with inlet temperature set to 56°C. Sodium oxybate MR coated particles with mean diameter of 370 microns were obtained.

036649.3 g of sodium oxybate MR particles were mixed with 0.52g of magnesium stearate (from Peter Greven) and 0.26g of colloidal silicon dioxide (Aerosil^™ 200 from Evonik). The dissolution profile of 4000mg of the mixture which correspond to 2250mg of sodium oxybate per vessel was determined using the USP apparatus 2 in 900ml of 0.1N HCl medium and pH 6.8 phosphate buffer (0.05M monobasic potassium phosphate solution - pH adjusted to 6.8 with 5N NaOH). Dissolution medium temperature was maintained at 37.0 ± 0.5 °C, and the rotating paddle speed was set at 100 rpm. The release profile in 0.1N HCl and pH 6.8 phosphate buffer is shown below in <figref idref="f0024">Figure 48</figref> and Tables 14a and 14b. <tables id="tabl0077" num="0077"><table frame="all"><title>Table 14a.Dissolution data - 0.1N HCl</title><tgroup cols="2"><colspec colnum="1" colname="col1" colwidth="24mm" align="center" /><colspec colnum="2" colname="col2" colwidth="29mm" align="center" /><thead valign="top"><row><entry>Time (h)</entry><entry>% dissolved</entry></row></thead><tbody><row><entry>0</entry><entry>0</entry></row><row><entry>0,25</entry><entry>0</entry></row><row><entry>1</entry><entry>1</entry></row><row><entry>3</entry><entry>2</entry></row><row><entry>6</entry><entry>3</entry></row><row><entry>8</entry><entry>7</entry></row><row><entry>10</entry><entry>18</entry></row><row><entry>12</entry><entry>37</entry></row><row><entry>16</entry><entry>75</entry></row></tbody></tgroup></table></tables><tables id="tabl0078" num="0078"><table frame="all"><title>Table 14b. Dissolution data - 50mM pH 6.8 phosphate buffer</title><tgroup cols="2"><colspec colnum="1" colname="col1" colwidth="40mm" align="center" /><colspec colnum="2" colname="col2" colwidth="45mm" align="center" /><thead valign="top"><row><entry>Time (h)</entry><entry>% dissolved</entry></row></thead><tbody><row><entry>0</entry><entry>0</entry></row><row><entry>0,25</entry><entry>9</entry></row><row><entry>0,5</entry><entry>95</entry></row><row><entry>1</entry><entry>101</entry></row><row><entry>3</entry><entry>101</entry></row></tbody></tgroup></table></tables>

0367The qualitative composition of 4.5g dose units comprising 50% of the dose as IR fraction and 50% of the dose as MR fraction is described in Table 14c. <tables id="tabl0079" num="0079"><table frame="all"><title>Table 14c</title><tgroup cols="3"><colspec colnum="1" colname="col1" colwidth="37mm" /><colspec colnum="2" colname="col2" colwidth="70mm" /><colspec colnum="3" colname="col3" colwidth="44mm" align="center" /><thead valign="top"><row><entry align="center">Component</entry><entry align="center">Function</entry><entry>Quantity per 4.5 g dose (g)</entry></row></thead><tbody><row><entry>MR microparticles</entry><entry>Modified release fraction of sodium oxybate</entry><entry>2.786</entry></row><row valign="middle"><entry>IR microparticles</entry><entry>Immediate release fraction of sodium oxybate</entry><entry>3.981</entry></row><row valign="middle"><entry>Malic acid</entry><entry>Acidifying agent</entry><entry>0.113</entry></row><row valign="middle"><entry>Xanthan gum</entry><entry>Suspending agent</entry><entry>0.050</entry></row><row valign="middle"><entry>Hydroxyethylcellulose</entry><entry>Suspending agent</entry><entry>0.075</entry></row><row valign="middle"><entry>Carrageenan gum</entry><entry>Suspending agent</entry><entry>0.075</entry></row><row><entry valign="bottom">Magnesium stearate</entry><entry>Lubricant</entry><entry>0.037</entry></row><row valign="middle"><entry>Total</entry><entry /><entry>7.115</entry></row></tbody></tgroup></table></tables>

0368After reconstitution with 50ml of tap water and rinsing with 10ml of tap water, the finished composition is expected to provide the dissolution profiles in <figref idref="f0025">Figures 49 and 50</figref> and Table 14d and 14e in 840ml of 0.1N HCl and in pH6.8 phosphate buffer (0.05M monobasic potassium phosphate solution with pH adjusted to 6.8 with 5N NaOH) using a USP apparatus 2, at 37.0 ± 0.5°C and the rotating paddle speed at 75 rpm. <tables id="tabl0080" num="0080"><table frame="all"><title>Table 14d</title><tgroup cols="2"><colspec colnum="1" colname="col1" colwidth="23mm" align="center" /><colspec colnum="2" colname="col2" colwidth="41mm" align="center" /><thead valign="top"><row><entry>Time (hour)</entry><entry>% dissolved in 0.1N HCl</entry></row></thead><tbody><row><entry>0</entry><entry>0</entry></row><row><entry>0.25</entry><entry>50</entry></row><row><entry>1</entry><entry>51</entry></row><row><entry>4</entry><entry>51</entry></row><row><entry>6</entry><entry>52</entry></row><row><entry>8</entry><entry>53</entry></row><row><entry>10</entry><entry>59</entry></row><row><entry>12</entry><entry>69</entry></row><row><entry>16</entry><entry>87</entry></row></tbody></tgroup></table></tables><tables id="tabl0081" num="0081"><table frame="all"><title>Table 14e</title><tgroup cols="2"><colspec colnum="1" colname="col1" colwidth="23mm" align="center" /><colspec colnum="2" colname="col2" colwidth="46mm" align="center" /><thead valign="top"><row><entry>Time (hour)</entry><entry>% dissolved in pH 6.8 buffer</entry></row></thead><tbody><row><entry>0</entry><entry>0</entry></row><row><entry>0,25</entry><entry>55</entry></row><row><entry>1</entry><entry>101</entry></row><row><entry>3</entry><entry>101</entry></row></tbody></tgroup></table></tables>

EXAMPLE 15. MR MICROPARTICLES WITH DIFFERENT RATIOS OF LUBRITAB^™ AND EUDRAGIT^™

0369Different prototypes were developed to evaluate the effect of the ratio between Lubritab^™ and Eudragit^™ on the formulation.

Example 15a -- 30% Lubritab

™

; Cellets

™

127; Coating level = 35%

0370IR particles were prepared as follows: 1615.0g of Sodium Oxybate and 85.0g of water soluble polymer polyvinylpyrrolidone (Povidone - Plasdone^™ K30 from ISP) were solubilized in 1894.3g of absolute ethyl alcohol and 1262.9g of water. The solution was entirely sprayed onto 300g of microcrystalline cellulose spheres (Cellets^™ 100 from Pharmatrans) in a fluid bed spray coater apparatus GPCG1.1. Sodium oxybate IR particles with mean diameter of 272 microns were obtained.

0371MR coated particles were prepared as follows: 50.2g of Methacrylic acid copolymer Type C (Eudragit^™ L100-55 from Evonik), 100.6g of Methacrylic acid copolymer Type B (Eudragit^™ S100 from Evonik), 64.6g of Hydrogenated cottonseed oil (Lubritab^™ from JRS), were dissolved in 1943.5g of isopropanol at 78°C. The solution was sprayed entirely on 400.0g of IR particles in a fluid bed spray coater apparatus Glatt^™ G.P.C.G.1.1 with inlet temperature 48°C, spraying rate around 11.0g per min and atomization pressure 1.3 bar. MR microparticles were dried for 2 hours with inlet temperature set to 56°C. Sodium oxybate MR coated particles with mean diameter of 403 microns were obtained.

037217.9 g of sodium oxybate MR microparticles were mixed with 0.1g of magnesium stearate (from Peter Greven). The dissolution profile of 4308mg of the mixture which corresponds to 2250mg of sodium oxybate per vessel was determined using the USP apparatus 2 in 900ml of 0.1N HCl medium. Dissolution medium temperature was maintained at 37.0 ± 0.5 °C, and the rotating paddle speed was set at 75 rpm. The release profile is shown in <figref idref="f0026">Figure 51</figref> and Table 15a. <tables id="tabl0082" num="0082"><table frame="all"><title>Table 15a</title><tgroup cols="2"><colspec colnum="1" colname="col1" colwidth="18mm" align="center" /><colspec colnum="2" colname="col2" colwidth="41mm" align="center" /><thead valign="top"><row><entry>Time (h)</entry><entry>% dissolved in 0.1N HCl</entry></row></thead><tbody><row><entry>0</entry><entry>0</entry></row><row><entry>0,25</entry><entry>3</entry></row><row><entry>1</entry><entry>5</entry></row><row><entry>3</entry><entry>69</entry></row><row><entry>4</entry><entry>96</entry></row><row><entry>6</entry><entry>101</entry></row><row><entry>8</entry><entry>102</entry></row><row><entry>10</entry><entry>102</entry></row></tbody></tgroup></table></tables>

0373Alternative MR coated particles of sodium oxybate were prepared according to the above manufacturing protocol with the coating level adjusted to 50% instead of 35%. The dissolution profile of the alternative sodium oxybate MR particles was determined using the same protocol as above. The 0.1N HCl dissolution profile is shown in <figref idref="f0026">Figure 52</figref> and Table 15b. <tables id="tabl0083" num="0083"><table frame="all"><title>Table 15b</title><tgroup cols="2"><colspec colnum="1" colname="col1" colwidth="19mm" align="center" /><colspec colnum="2" colname="col2" colwidth="24mm" align="center" /><thead valign="top"><row><entry>Time (h)</entry><entry>% dissolved</entry></row></thead><tbody><row><entry>0</entry><entry>0</entry></row><row><entry>0,25</entry><entry>1</entry></row><row><entry>1</entry><entry>1</entry></row><row><entry>3</entry><entry>36</entry></row><row><entry>4</entry><entry>67</entry></row><row><entry>6</entry><entry>95</entry></row><row><entry>8</entry><entry>98</entry></row><row><entry>10</entry><entry>98</entry></row></tbody></tgroup></table></tables>

0374The finished composition, which contains a 50:50 mixture of MR and IR sodium oxybate particles calculated on their sodium oxybate content, was prepared as follows: 153.3g of the above IR microparticles, 235.8g of the above sodium oxybate MR microparticles with a coating level of 30%, 6.2g of malic acid (D/L malic acid regular from Bartek), 2.7g of xanthan gum (Xantural^™ 75 from CP Kelco), 4.1g of carragenan gum (Viscarin^™ PH109 from FMC Biopolymer), 4.1g of hydroxyethylcellulose (Natrosol^™ 250M from Ashland ) and 2.0g of magnesium stearate (from Peter Greven) were mixed in a Roue-Roehn mixer. Individual doses of 7.42g (corresponding to a 4.5g dose with half of the dose as immediate-release fraction and half of the dose as modified release fraction) were weighed.

0375<figref idref="f0027">Figure 53</figref> and Table 15c below depict dissolution profiles determined using a USP apparatus 2 in 0.1N HCl. The dissolution medium was maintained at 37.0 ± 0.5°C and the rotating paddle speed was fixed at 75 rpm. Single dose units were poured in a container containing 50 mL of tap water. After 5 minutes, the suspension was poured in the dissolution vessel containing 840 mL of 0.1N HCl dissolution medium. 10 mL of water were used to rinse the container and were added to the dissolution vessel. <tables id="tabl0084" num="0084"><table frame="all"><title>Table 15c</title><tgroup cols="2"><colspec colnum="1" colname="col1" colwidth="23mm" align="center" /><colspec colnum="2" colname="col2" colwidth="23mm" align="center" /><thead valign="top"><row><entry>Time (hour)</entry><entry>% dissolved</entry></row></thead><tbody><row><entry>0</entry><entry>0</entry></row><row><entry>0,25</entry><entry>45</entry></row><row><entry>1</entry><entry>52</entry></row><row><entry>2</entry><entry>92</entry></row><row><entry>3</entry><entry>94</entry></row><row><entry>4</entry><entry>97</entry></row><row><entry>6</entry><entry>97</entry></row><row><entry>8</entry><entry>97</entry></row><row><entry>10</entry><entry>96</entry></row></tbody></tgroup></table></tables>

Example 15b -- Celphere

™

CP203 as neutral cores and coating level = 35%

0376IR particles were prepared as follows: 665.0g of Sodium Oxybate and 35.0g of water soluble polymer polyvinylpyrrolidone (Povidone - Plasdone^™ K30 from ISP) were solubilized in 781.2g of absolute ethyl alcohol and 521.6g of water. The solution was entirely sprayed onto 300g of microcrystalline cellulose spheres (Celphere^™ CP203 from Asahi Kasei - mean diameter D[4,3]=250 microns) in a fluid bed spray coater apparatus GPCG1.1. Sodium oxybate IR particles with mean diameter of 398 microns were obtained.

0377MR coated particles were prepared as follows: 37.6g of Methacrylic acid copolymer Type C (Eudragit^™ L100-55 from Evonik), 75.4g of Methacrylic acid copolymer Type B (Eudragit^™ S100 from Evonik), 48.5g of Hydrogenated cottonseed oil (Lubritab^™ from JRS), were dissolved in 1458.0g of isopropanol at 78°C. The solution was sprayed entirely on 300.0g of IR particles in a fluid bed spray coater apparatus Glatt^™ G.P.C.G.1.1 with inlet temperature 48°C, spraying rate around 11.7g per min and atomization pressure 1.6 bar. MR microparticles were dried for 2 hours with inlet temperature set to 56°C. Sodium oxybate MR coated particles with mean diameter of 491 microns were obtained.

037817.0 g of MR microparticles were mixed with 0.08g of magnesium stearate (from Peter Greven). The dissolution profile of 5210mg of the mixture which corresponds to 2250mg of sodium oxybate per vessel was determined using the USP apparatus 2 in 900ml of 0.1N HCl medium and in pH 6.8 phosphate buffer (0.05M monobasic potassium phosphate solution - pH adjusted to 6.8 with 5N NaOH). Dissolution medium temperature was maintained at 37.0 ± 0.5 °C, and the rotating paddle speed was set at 75 rpm. The release profile is shown in <figref idref="f0027">Figure 54</figref> and Tables 15d and 15e. <tables id="tabl0085" num="0085"><table frame="all"><title>Table 15d. Dissolution data - 0.1N HCl</title><tgroup cols="2"><colspec colnum="1" colname="col1" colwidth="27mm" align="center" /><colspec colnum="2" colname="col2" colwidth="27mm" align="center" /><thead valign="top"><row><entry>Time (hour)</entry><entry>% dissolved</entry></row></thead><tbody><row><entry>0</entry><entry>0</entry></row><row><entry>0,25</entry><entry>3</entry></row><row><entry>1</entry><entry>3</entry></row><row><entry>3</entry><entry>45</entry></row><row><entry>4</entry><entry>77</entry></row><row><entry>6</entry><entry>96</entry></row><row><entry>8</entry><entry>98</entry></row><row><entry>10</entry><entry>98</entry></row></tbody></tgroup></table></tables><tables id="tabl0086" num="0086"><table frame="all"><title>Table 15e.Dissolution data - 50mM pH 6.8 phosphate buffer</title><tgroup cols="2"><colspec colnum="1" colname="col1" colwidth="39mm" align="center" /><colspec colnum="2" colname="col2" colwidth="44mm" align="center" /><thead valign="top"><row><entry>Time (h)</entry><entry>% dissolved</entry></row></thead><tbody><row><entry>0</entry><entry>0</entry></row><row><entry>0,25</entry><entry>1</entry></row><row><entry>0,5</entry><entry>22</entry></row><row><entry>0,75</entry><entry>87</entry></row><row><entry>1</entry><entry>98</entry></row><row><entry>2</entry><entry>97</entry></row></tbody></tgroup></table></tables>

0379The qualitative composition of 4.5g dose units comprising 50% of the dose as IR fraction and 50% of the dose as MR fraction is described in Table 15f. <tables id="tabl0087" num="0087"><table frame="all"><title>Table 15f</title><tgroup cols="3"><colspec colnum="1" colname="col1" colwidth="35mm" /><colspec colnum="2" colname="col2" colwidth="70mm" /><colspec colnum="3" colname="col3" colwidth="44mm" align="center" /><thead valign="top"><row><entry align="center">Component</entry><entry>Function</entry><entry>Quantity per 4.5 g dose (g)</entry></row></thead><tbody><row><entry>MR microparticles</entry><entry>Modified release fraction of sodium oxybate</entry><entry>5.205</entry></row><row><entry>IR microparticles</entry><entry>Immediate release fraction of sodium oxybate</entry><entry>3.383</entry></row><row><entry>Malic acid</entry><entry>Acidifying agent</entry><entry>0.113</entry></row><row><entry>Xanthan gum</entry><entry>Suspending agent</entry><entry>0.050</entry></row><row><entry>Hydroxyethylcellulo</entry><entry>Suspending agent</entry><entry>0.075</entry></row><row><entry>Carrageenan gum</entry><entry>Suspending agent</entry><entry>0.075</entry></row><row><entry>Magnesium stearate</entry><entry>Lubricant</entry><entry>0.045</entry></row><row><entry>Total</entry><entry /><entry>8.946</entry></row></tbody></tgroup></table></tables>

0380After reconstitution, the finished composition is expected to exhibit the dissolution profiles in <figref idref="f0028">Figures 55 and 56</figref> and Tables 15g and 15h in 0.1N HCl and in pH6.8 phosphate buffer (0.05M monobasic potassium phosphate solution with pH adjusted to 6.8 with 5N NaOH) using a USP apparatus 2, at 37.0 ± 0.5°C and the rotating paddle speed at 75 rpm. <tables id="tabl0088" num="0088"><table frame="all"><title>Table 15g</title><tgroup cols="2"><colspec colnum="1" colname="col1" colwidth="18mm" align="center" /><colspec colnum="2" colname="col2" colwidth="41mm" align="center" /><thead valign="middle"><row><entry>Time (h)</entry><entry>% dissolved in 0.1N HCl</entry></row></thead><tbody valign="middle"><row><entry>0</entry><entry>0</entry></row><row><entry>0,25</entry><entry>51</entry></row><row><entry>1</entry><entry>51</entry></row><row><entry>3</entry><entry>73</entry></row><row><entry>4</entry><entry>88</entry></row><row><entry>6</entry><entry>98</entry></row><row><entry>8</entry><entry>99</entry></row><row><entry>10</entry><entry>99</entry></row></tbody></tgroup></table></tables><tables id="tabl0089" num="0089"><table frame="all"><title>Table 15h</title><tgroup cols="2"><colspec colnum="1" colname="col1" colwidth="18mm" align="center" /><colspec colnum="2" colname="col2" colwidth="46mm" align="center" /><thead valign="middle"><row><entry>Time (h)</entry><entry>% dissolved in pH 6.8 buffer</entry></row></thead><tbody valign="middle"><row><entry>0</entry><entry>0</entry></row><row><entry>0,25</entry><entry>50</entry></row><row><entry>0,5</entry><entry>61</entry></row><row><entry>0,75</entry><entry>93</entry></row><row><entry>1</entry><entry>99</entry></row><row><entry>2</entry><entry>99</entry></row></tbody></tgroup></table></tables>

Example 15c -- 40% Lubritab

™

(Coating level=40%)

0381IR pellets were prepared as follows: 1615.0g of Sodium Oxybate and 85.0g of water soluble polymer polyvinylpyrrolidone (Povidone - Plasdone^™ K30 from ISP) were solubilized in 1903.2g of absolute ethyl alcohol and 1267.1g of water. The solution was entirely sprayed onto 300g of microcrystalline cellulose spheres (Cellets^™ 127 from Pharmatrans) in a fluid bed spray coater apparatus GPCG1.1. Sodium oxybate IR particles with mean diameter of 268 microns were obtained.

0382MR coated particles were prepared as follows: 40.6g of Methacrylic acid copolymer Type C (Eudragit^™ L100-55 from Evonik), 80.1g of Methacrylic acid copolymer Type B (Eudragit^™ S100 from Evonik), 80.5g of Hydrogenated cottonseed oil (Lubritab^™ from JRS), were dissolved in 1799.4g of isopropanol at 78°C. The solution was sprayed entirely on 300.0g of IR particles in a fluid bed spray coater apparatus Glatt^™ G.P.C.G.1.1 with inlet temperature 48°C, spraying rate around 10.5g per min and atomization pressure 1.3 bar. MR microparticles were dried for 2 hours with inlet temperature set to 56°C. Sodium oxybate MR coated particles with mean diameter of 348 microns were obtained.

038320.0 g of MR coated particles were mixed with 0.1g of magnesium stearate (from Peter Greven). The dissolution profile of 4700mg of the mixture which corresponds to 2250mg of sodium oxybate per vessel was determined using the USP apparatus 2 in 900ml of 0.1N HCl medium. Dissolution medium temperature was maintained at 37.0 ± 0.5 °C, and the rotating paddle speed was set at 75 rpm. The release profile is shown in <figref idref="f0029">Figure 57</figref> and Table 15i. <tables id="tabl0090" num="0090"><table frame="all"><title>Table 15i</title><tgroup cols="2"><colspec colnum="1" colname="col1" colwidth="18mm" align="center" /><colspec colnum="2" colname="col2" colwidth="41mm" align="center" /><thead valign="middle"><row><entry>Time (h)</entry><entry>% dissolved in 0.1N HCl</entry></row></thead><tbody valign="middle"><row><entry>0</entry><entry>0</entry></row><row><entry>0,25</entry><entry>0</entry></row><row><entry>1</entry><entry>0</entry></row><row><entry>3</entry><entry>1</entry></row><row><entry>4</entry><entry>8</entry></row><row><entry>6</entry><entry>52</entry></row><row><entry>8</entry><entry>84</entry></row><row><entry>10</entry><entry>95</entry></row><row><entry>12</entry><entry>97</entry></row><row><entry>16</entry><entry>98</entry></row></tbody></tgroup></table></tables>

0384The finished composition, which contains a 50:50 mixture of MR and IR particles calculated on their sodium oxybate content, was prepared as follows: 156.0g of the above IR particles, 260.0g of the above MR coated particles, 6.3g of malic acid (D/L malic acid regular from Bartek), 2.8g of xanthan gum (Xantural^™ 75 from CP Kelco), 4.2g of carragenan gum (Viscarin^™ PH209 from FMC Biopolymer), 4.2g of hydroxyethylcellulose (Natrosol^™ 250M from Ashland ) and 2.2g of magnesium stearate (from Peter Greven) were mixed in a Roue-Roehn mixer. Individual doses of 7.78g (corresponding to a 4.5g dose with half of the dose as immediate-release fraction and half of the dose as modified release fraction) were weighed.

0385<figref idref="f0029">Figures 58</figref> and <figref idref="f0030">59</figref> and Tables 15j and 15k below depict dissolution profiles determined in 0.1N HCl and pH 6.8 buffer (0.05M monobasic potassium phosphate solution with pH adjusted to 6.8 with 5N NaOH) using a USP apparatus 2. The dissolution medium was maintained at 37.0 ± 0.5°C and the rotating paddle speed was fixed at 75 rpm. Single dose units were poured in a container containing 50 mL of tap water. After 5 minutes, the suspension was poured in the dissolution vessel containing 840 mL of 0.1N HCl dissolution medium. 10 mL of water were used to rinse the container and were added to the dissolution vessel. <tables id="tabl0091" num="0091"><table frame="all"><title>Table 15j</title><tgroup cols="2"><colspec colnum="1" colname="col1" colwidth="18mm" align="center" /><colspec colnum="2" colname="col2" colwidth="41mm" align="center" /><thead valign="middle"><row><entry>Time (h)</entry><entry>% dissolved in 0.1N HCl</entry></row></thead><tbody valign="middle"><row><entry>0</entry><entry>0</entry></row><row><entry>0,25</entry><entry>48</entry></row><row><entry>1</entry><entry>52</entry></row><row><entry>3</entry><entry>52</entry></row><row><entry>4</entry><entry>62</entry></row><row><entry>6</entry><entry>89</entry></row><row><entry>8</entry><entry>96</entry></row><row><entry>10</entry><entry>97</entry></row><row><entry>12</entry><entry>98</entry></row><row><entry>16</entry><entry>98</entry></row><row><entry>20</entry><entry>97</entry></row></tbody></tgroup></table></tables><tables id="tabl0092" num="0092"><table frame="all"><title>Table 15k</title><tgroup cols="2"><colspec colnum="1" colname="col1" colwidth="18mm" align="center" /><colspec colnum="2" colname="col2" colwidth="46mm" align="center" /><thead valign="middle"><row><entry>Time (h)</entry><entry>% dissolved in pH 6.8 buffer</entry></row></thead><tbody valign="middle"><row><entry>0</entry><entry>0</entry></row><row><entry>0,25</entry><entry>49</entry></row><row><entry>0,5</entry><entry>85</entry></row><row><entry>1</entry><entry>91</entry></row><row><entry>2</entry><entry>96</entry></row><row><entry>3</entry><entry>104</entry></row></tbody></tgroup></table></tables>

Example 15d -- 70% Lubritab

™

(coating level 25%)

0386IR particles were prepared as follows: 1615.1g of Sodium Oxybate and 85.0g of water soluble polymer polyvinylpyrrolidone (Povidone - Plasdone^™ K30 from ISP) were solubilized in 1894.4g of absolute ethyl alcohol and 1262.9g of water. The solution was entirely sprayed onto 300g of microcrystalline cellulose spheres (Cellets^™ 127 from Pharmatrans) in a fluid bed spray coater apparatus GPCG1.1. Sodium oxybate IR particles with mean diameter of 272 microns were obtained.

0387MR coated particles were prepared as follows: 13.3g of Methacrylic acid copolymer Type C (Eudragit^™ L100-55 from Evonik), 26.8g of Methacrylic acid copolymer Type B (Eudragit^™ S100 from Evonik), 93.3g of Hydrogenated cottonseed oil (Lubritab^™ from JRS), were dissolved in 1200.3g of isopropanol at 78°C. The solution was sprayed entirely on 400.0g of IR particles in a fluid bed spray coater apparatus Glatt^™ G.P.C.G.1.1 with inlet temperature 48°C, spraying rate around 10.6g per min and atomization pressure 1.3 bar. MR microparticles were dried for 2 hours with inlet temperature set to 56°C. Sodium oxybate MR coated particles with mean diameter of 313 microns were obtained.

038817.0 g of MR coated particles were mixed with 0.06g of magnesium stearate (from Peter Greven). The dissolution profile of 3750mg of the mixture which corresponds to 2250mg of sodium oxybate per vessel was determined using the USP apparatus 2 in 900ml of 0.1N HCl medium and pH6.8 phosphate buffer (0.05M monobasic potassium phosphate solution - pH adjusted to 6.8 with 5N NaOH). Dissolution medium temperature was maintained at 37.0 ± 0.5 °C, and the rotating paddle speed was set at 75 rpm. The release profile is shown in <figref idref="f0030">Figure 60</figref> and Tables 151 and 15m. <tables id="tabl0093" num="0093"><table frame="all"><title>Table 151. Dissolution profile in 0.1N HCl</title><tgroup cols="2"><colspec colnum="1" colname="col1" colwidth="26mm" align="center" /><colspec colnum="2" colname="col2" colwidth="31mm" align="center" /><thead valign="middle"><row><entry>Time (h)</entry><entry>% dissolved</entry></row></thead><tbody valign="middle"><row><entry>0</entry><entry>0,0</entry></row><row><entry>0,25</entry><entry>5</entry></row><row><entry>1</entry><entry>4</entry></row><row><entry>3</entry><entry>5</entry></row><row><entry>4</entry><entry>5</entry></row><row><entry>6</entry><entry>8</entry></row><row><entry>8</entry><entry>33</entry></row><row><entry>10</entry><entry>78</entry></row><row><entry>12</entry><entry>98</entry></row><row><entry>16</entry><entry>103</entry></row></tbody></tgroup></table></tables><tables id="tabl0094" num="0094"><table frame="all"><title>Table 15m. Dissolution profile in 50mM pH 6.8 phosphate buffer</title><tgroup cols="2"><colspec colnum="1" colname="col1" colwidth="42mm" align="center" /><colspec colnum="2" colname="col2" colwidth="47mm" align="center" /><thead valign="middle"><row><entry>Time (h)</entry><entry>% dissolved</entry></row></thead><tbody valign="middle"><row><entry>0</entry><entry>0,0</entry></row><row><entry>0,25</entry><entry>1</entry></row><row><entry>0,5</entry><entry>45</entry></row><row><entry>1</entry><entry>97</entry></row><row><entry>2</entry><entry>108</entry></row><row><entry>3</entry><entry>114</entry></row></tbody></tgroup></table></tables>

0389The finished composition, which contains a 50:50 mixture of MR and IR particles calculated on their sodium oxybate content, was prepared as follows: 153.3g of the above IR particles, 204.3g of the above MR coated particles, 6.2g of Malic acid (D/L malic acid regular from Bartek), 2.7g of xanthan gum (Xantural^™ 75 from CP Kelco), 4.1g of carragenan gum (Viscarin^™ PH209 from FMC Biopolymer), 4.1g of hydroxyethylcellulose (Natrosol^™ 250M from Ashland ) and 1.9g of magnesium stearate (from Peter Greven) were mixed in a Roue-Roehn mixer. Individual doses of 6.85g (corresponding to a 4.5g dose with half of the dose as immediate-release fraction and half of the dose as modified release fraction) were weighed.

0390<figref idref="f0031">Figures 61</figref> and Table 15n depict the dissolution profiles determined in 0.1N HCl using a USP apparatus 2. The dissolution medium was maintained at 37.0 ± 0.5°C and the rotating paddle speed was fixed at 75 rpm. Single dose units were poured in a container containing 50 mL of tap water. After 5 minutes, the suspension was poured in the dissolution vessel containing 840 mL of 0.1N HCl dissolution medium. 10 mL of water were used to rinse the container and were added to the dissolution vessel. <tables id="tabl0095" num="0095"><table frame="all"><title>Table 15n</title><tgroup cols="2"><colspec colnum="1" colname="col1" colwidth="19mm" align="center" /><colspec colnum="2" colname="col2" colwidth="24mm" align="center" /><thead valign="middle"><row><entry>Time (h)</entry><entry>% dissolved</entry></row></thead><tbody valign="middle"><row><entry>0</entry><entry>0</entry></row><row><entry>0,25</entry><entry>48</entry></row><row><entry>1</entry><entry>52</entry></row><row><entry>3</entry><entry>52</entry></row><row><entry>4</entry><entry>52</entry></row><row><entry>6</entry><entry>55</entry></row><row><entry>8</entry><entry>76</entry></row><row><entry>10</entry><entry>95</entry></row><row><entry>12</entry><entry>100</entry></row><row><entry>16</entry><entry>100</entry></row><row><entry>20</entry><entry>100</entry></row></tbody></tgroup></table></tables>

0391Based on the dissolution profile of the MR coated particles in pH 6.8 phosphate buffer, single dose units are expected to have the dissolution profile in pH6.8 buffer shown in <figref idref="f0031">Figure 62</figref> and in Table 15o. <tables id="tabl0096" num="0096"><table frame="all"><title>Table 15o</title><tgroup cols="2"><colspec colnum="1" colname="col1" colwidth="18mm" align="center" /><colspec colnum="2" colname="col2" colwidth="46mm" align="center" /><thead valign="middle"><row><entry>Time (h)</entry><entry>% dissolved in pH 6.8 buffer</entry></row></thead><tbody valign="middle"><row><entry>0</entry><entry>0,0</entry></row><row><entry>0,25</entry><entry>51</entry></row><row><entry>0,5</entry><entry>72</entry></row><row><entry>1</entry><entry>99</entry></row><row><entry>2</entry><entry>104</entry></row><row><entry>3</entry><entry>107</entry></row></tbody></tgroup></table></tables>

EXAMPLE 16. EVALUATION OF DIFFERENT HYDROPHOBIC COMPOUNDS IN THE COATING

0392Prototypes with different hydrophobic coatings were prepared and evaluated to determine the effect of coating type on the dissolution of the formulations.

Example 16a -- Glyceryl dibehenate (Compritol

™

ATO888)

0393IR particles were prepared as follows: 1615.0g of Sodium Oxybate and 85.0g of water soluble polymer polyvinylpyrrolidone (Povidone - Plasdone^™ K30 from ISP) were solubilized in 1903.2g of absolute ethyl alcohol and 1267.1g of water. The solution was entirely sprayed onto 300g of microcrystalline cellulose spheres (Cellets^™ 127 from Pharmatrans) in a fluid bed spray coater apparatus GPCG1.1. Sodium oxybate IR particles with mean diameter of 268 microns were obtained.

0394MR coated particles were prepared as follows: 22.9g of Methacrylic acid copolymer Type C (Eudragit^™ L100-55 from Evonik), 45.8g of Methacrylic acid copolymer Type B (Eudragit^™ S100 from Evonik), 102;9g of glyceryl dibehenate (Compritol^™ ATO 888 from Gattefossé), were dissolved in 1371.8g of isopropanol at 78°C. The solution was sprayed entirely on 400.0g of IR particles in a fluid bed spray coater apparatus Glatt^™ G.P.C.G.1.1 with inlet temperature 48°C, spraying rate around 11.7g per min and atomization pressure 1.6 bar. MR microparticles were dried for 2 hours with inlet temperature set to 56°C. Sodium oxybate MR coated particles with mean diameter of 322 microns were obtained.

039517.0 g of MR coated particles were mixed with 0.1g of magnesium stearate (from Peter Greven). The dissolution profile of 4000mg of the mixture which corresponds to 2250mg of sodium oxybate per vessel was determined using the USP apparatus 2 in 900ml of 0.1N HCl medium and in pH 6.8 phosphate buffer (0.05M monobasic potassium phosphate solution - pH adjusted to 6.8 with 5N NaOH). Dissolution medium temperature was maintained at 37.0 ± 0.5 °C, and the rotating paddle speed was set at 75 rpm. The release profile is shown in <figref idref="f0032">Figure 63</figref> and Tables 16a and 16b. <tables id="tabl0097" num="0097"><table frame="all"><title>Table 16a.Dissolution profile - 0.1N HCl</title><tgroup cols="2"><colspec colnum="1" colname="col1" colwidth="25mm" align="center" /><colspec colnum="2" colname="col2" colwidth="30mm" align="center" /><thead valign="middle"><row><entry>Time (h)</entry><entry>% dissolved</entry></row></thead><tbody valign="middle"><row><entry>0</entry><entry>0</entry></row><row><entry>0,25</entry><entry>0</entry></row><row><entry>1</entry><entry>1</entry></row><row><entry>3</entry><entry>3</entry></row><row><entry>4</entry><entry>6</entry></row><row><entry>6</entry><entry>31</entry></row><row><entry>8</entry><entry>67</entry></row><row><entry>10</entry><entry>90</entry></row><row><entry>12</entry><entry>98</entry></row><row><entry>16</entry><entry>100</entry></row></tbody></tgroup></table></tables><tables id="tabl0098" num="0098"><table frame="all"><title>Table 16b. Dissolution profile - 50mM pH6.8 phosphate buffer</title><tgroup cols="2"><colspec colnum="1" colname="col1" colwidth="41mm" align="center" /><colspec colnum="2" colname="col2" colwidth="46mm" align="center" /><thead valign="middle"><row><entry>Time (h)</entry><entry>% dissolved</entry></row></thead><tbody valign="middle"><row><entry>0</entry><entry>0</entry></row><row><entry>0,25</entry><entry>1</entry></row><row><entry>1</entry><entry>102</entry></row><row><entry>3</entry><entry>105</entry></row></tbody></tgroup></table></tables>

0396The finished composition, which contains a 50:50 mixture of MR and IR particles calculated on their sodium oxybate content, was prepared as follows: 181.1g of the above IR particles, 258.7g of the above MR coated particles, 7.3g of Malic acid (D/L malic acid regular from Bartek), 3.3g of xanthan gum (Xantural^™ 75 from CP Kelco), 4.9g of carragenan gum (Viscarin^™ PH209 from FMC Biopolymer), 4.9g of hydroxyethylcellulose (Natrosol^™ 250M from Ashland ) and 2.3g of magnesium stearate (from Peter Greven) were mixed in a Roue-Roehn mixer. Individual doses of 7.12g (corresponding to a 4.5g dose with half of the dose as immediate-release fraction and half of the dose as modified release fraction) were weighed.

0397<figref idref="f0032">Figures 64</figref> and Table 16c depict dissolution profiles determined in 0.1N HCl using a USP apparatus 2. The dissolution medium was maintained at 37.0 ± 0.5°C and the rotating paddle speed was fixed at 75 rpm. Single dose units were poured in a container containing 50 mL of tap water. After 5 minutes, the suspension was poured in the dissolution vessel containing 840 mL of 0.1N HCl dissolution medium. 10 mL of water were used to rinse the container and were added to the dissolution vessel. <tables id="tabl0099" num="0099"><table frame="all"><title>Table 16c</title><tgroup cols="2"><colspec colnum="1" colname="col1" colwidth="23mm" align="center" /><colspec colnum="2" colname="col2" colwidth="41mm" align="center" /><thead valign="middle"><row><entry>Time (hour)</entry><entry>% dissolved in 0.1N HCl</entry></row></thead><tbody valign="middle"><row><entry>0</entry><entry>0</entry></row><row><entry>0,25</entry><entry>46</entry></row><row><entry>1</entry><entry>50</entry></row><row><entry>3</entry><entry>51</entry></row><row><entry>4</entry><entry>56</entry></row><row><entry>6</entry><entry>78</entry></row><row><entry>8</entry><entry>92</entry></row><row><entry>10</entry><entry>96</entry></row><row><entry>12</entry><entry>97</entry></row><row><entry>16</entry><entry>96</entry></row></tbody></tgroup></table></tables>

0398Based on the dissolution profile of the MR microparticles alone in pH 6.8 phosphate buffer, single dose units are expected to have the dissolution profile at pH6.8 shown in <figref idref="f0033">Figure 65</figref> and in Table 16d. <tables id="tabl0100" num="0100"><table frame="all"><title>Table 16d</title><tgroup cols="2"><colspec colnum="1" colname="col1" colwidth="23mm" align="center" /><colspec colnum="2" colname="col2" colwidth="46mm" align="center" /><thead valign="middle"><row><entry>Time (hour)</entry><entry>% dissolved in pH 6.8 buffer</entry></row></thead><tbody valign="middle"><row><entry>0</entry><entry>0</entry></row><row><entry>0,25</entry><entry>50</entry></row><row><entry>1</entry><entry>101</entry></row><row><entry>3</entry><entry>102</entry></row></tbody></tgroup></table></tables>

Example 16b -- 60% Candelilla wax with coating level of 20%

0399IR particles were prepared as follows: 1615.1g of Sodium Oxybate and 85.0g of water soluble polymer polyvinylpyrrolidone (Povidone - Plasdone^™ K30 from ISP) were solubilized in 1894.4g of absolute ethyl alcohol and 1262.9g of water. The solution was entirely sprayed onto 300g of microcrystalline cellulose spheres (Cellets^™ 127 from Pharmatrans) in a fluid bed spray coater apparatus GPCG1.1. Sodium oxybate IR particles with mean diameter of 255 microns were obtained.

0400MR coated particles were prepared as follows: 13.3g of Methacrylic acid copolymer Type C (Eudragit^™ L100-55 from Evonik), 26.7g of Methacrylic acid copolymer Type B (Eudragit^™ S100 from Evonik), 60.0g of candelilla wax (Kahlwax^™ 2039L from Brenntag), were dissolved in 902.2g of isopropanol at 78°C. The solution was sprayed entirely on 400.0g of IR particles in a fluid bed spray coater apparatus Glatt^™ G.P.C.G.1.1 with inlet temperature 48°C, spraying rate around 12.8g per min and atomization pressure 1.3 bar. MR microparticles were dried for 2 hours with inlet temperature set to 56°C. Sodium oxybate MR coated particles with mean diameter of 289 microns were obtained.

040121.2 g of MR microparticles were mixed with 0.11g of magnesium stearate (from Peter Greven). The dissolution profile of 4000mg of the mixture which corresponds to 2570mg of sodium oxybate per vessel was determined using the USP apparatus 2 in 900ml of 0.1N HCl medium and in pH 6.8 phosphate buffer (0.05M monobasic potassium phosphate solution - pH adjusted to 6.8 with 5N NaOH). Dissolution medium temperature was maintained at 37.0 ± 0.5 °C, and the rotating paddle speed was set at 75 rpm. The release profiles are shown below in <figref idref="f0033">Figure 66</figref> and Tables 16e and 16f. <tables id="tabl0101" num="0101"><table frame="all"><title>Table 16e.Dissolution profile - 0.1N HCl</title><tgroup cols="2"><colspec colnum="1" colname="col1" colwidth="25mm" align="center" /><colspec colnum="2" colname="col2" colwidth="30mm" align="center" /><thead valign="middle"><row><entry>Time (h)</entry><entry>% dissolved</entry></row></thead><tbody valign="middle"><row><entry>0</entry><entry>0</entry></row><row><entry>0,25</entry><entry>0</entry></row><row><entry>1</entry><entry>0</entry></row><row><entry>3</entry><entry>0</entry></row><row><entry>4</entry><entry>1</entry></row><row><entry>6</entry><entry>2</entry></row><row><entry>8</entry><entry>2</entry></row><row><entry>10</entry><entry>2</entry></row><row><entry>12</entry><entry>2</entry></row><row><entry>16</entry><entry>3</entry></row><row><entry>20</entry><entry>4</entry></row></tbody></tgroup></table></tables><tables id="tabl0102" num="0102"><table frame="all"><title>Table 16f. Dissolution profile - 50mM pH6.8 phosphate buffer</title><tgroup cols="2"><colspec colnum="1" colname="col1" colwidth="40mm" align="center" /><colspec colnum="2" colname="col2" colwidth="45mm" align="center" /><thead valign="middle"><row><entry>Time (h)</entry><entry>% dissolved</entry></row></thead><tbody valign="middle"><row><entry>0</entry><entry>0</entry></row><row><entry>0,25</entry><entry>0</entry></row><row><entry>0,5</entry><entry>10</entry></row><row><entry>0,75</entry><entry>62</entry></row><row><entry>1</entry><entry>89</entry></row><row><entry>2</entry><entry>101</entry></row></tbody></tgroup></table></tables>

0402The qualitative composition of 4.5g dose units comprising 50% of the dose as IR fraction and 50% of the dose as MR fraction is described in Table 16g. <tables id="tabl0103" num="0103"><table frame="all"><title>Table 16g</title><tgroup cols="3"><colspec colnum="1" colname="col1" colwidth="37mm" /><colspec colnum="2" colname="col2" colwidth="70mm" /><colspec colnum="3" colname="col3" colwidth="44mm" align="center" /><thead valign="middle"><row><entry align="center">Component</entry><entry align="center">Function</entry><entry>Quantity per 4.5 g dose (g)</entry></row></thead><tbody><row><entry>MR microparticles</entry><entry>Modified release fraction of sodium oxybate</entry><entry>3.483</entry></row><row valign="middle"><entry>IR microparticles</entry><entry>Immediate release fraction of sodium oxybate</entry><entry>2.786</entry></row><row valign="middle"><entry>Malic acid</entry><entry>Acidifying agent</entry><entry>0.113</entry></row><row valign="middle"><entry>Xanthan gum</entry><entry>Suspending agent</entry><entry>0.050</entry></row><row valign="middle"><entry>Hydroxyethylcellulose</entry><entry>Suspending agent</entry><entry>0.075</entry></row><row valign="middle"><entry>Carrageenan gum</entry><entry>Suspending agent</entry><entry>0.075</entry></row><row><entry valign="bottom">Magnesium stearate</entry><entry>Lubricant</entry><entry>0.033</entry></row><row valign="middle"><entry>Total</entry><entry /><entry>6.615</entry></row></tbody></tgroup></table></tables>

0403The finished composition, which contains a 50:50 mixture of MR and IR particles calculated on their sodium oxybate content, can be prepared as follows: 200.0g of the above IR particles, 250.0g of the above MR coated particles, 8.1g of Malic acid (D/L malic acid regular from Bartek), 3.6g of xanthan gum (Xantural^™ 75 from CP Kelco), 5.4g of carragenan gum (Viscarin^™ PH209 from FMC Biopolymer), 5.4g of hydroxyethylcellulose (Natrosol^™ 250M from Ashland ) and 2.4g of magnesium stearate (from Peter Greven) were mixed in a Roue-Roehn mixer. Individual doses of 6.61g (corresponding to a 4.5g dose with half of the dose as immediate-release fraction and half of the dose as modified release fraction) were weighed.

0404After reconstitution, the finished composition is expected to provide the dissolution profiles in <figref idref="f0034">Figures 67 and 68</figref> and Tables 16h and 16i in 0.1N HCl and in pH6.8 phosphate buffer (0.05M monobasic potassium phosphate solution with pH adjusted to 6.8 with 5N NaOH) using a USP apparatus 2, at 37.0 ± 0.5°C and the rotating paddle speed at 75 rpm. <tables id="tabl0104" num="0104"><table frame="all"><title>Table 16h</title><tgroup cols="2"><colspec colnum="1" colname="col1" colwidth="23mm" align="center" /><colspec colnum="2" colname="col2" colwidth="41mm" align="center" /><thead valign="middle"><row><entry>Time (hour)</entry><entry>% dissolved in 0.1N HCl</entry></row></thead><tbody valign="middle"><row><entry>0</entry><entry>0</entry></row><row><entry>0,25</entry><entry>50</entry></row><row><entry>1</entry><entry>50</entry></row><row><entry>3</entry><entry>50</entry></row><row><entry>4</entry><entry>50</entry></row><row><entry>6</entry><entry>51</entry></row><row><entry>8</entry><entry>51</entry></row><row><entry>10</entry><entry>51</entry></row><row><entry>12</entry><entry>51</entry></row><row><entry>16</entry><entry>52</entry></row><row><entry>20</entry><entry>52</entry></row></tbody></tgroup></table></tables><tables id="tabl0105" num="0105"><table frame="all"><title>Table 16i</title><tgroup cols="2"><colspec colnum="1" colname="col1" colwidth="23mm" align="center" /><colspec colnum="2" colname="col2" colwidth="45mm" align="center" /><thead valign="middle"><row><entry>Time (hour)</entry><entry>% dissolved in pH6.8 buffer</entry></row></thead><tbody valign="middle"><row><entry>0</entry><entry>0</entry></row><row><entry>0,25</entry><entry>50</entry></row><row><entry>0,5</entry><entry>55</entry></row><row><entry>0,75</entry><entry>81</entry></row><row><entry>1</entry><entry>94</entry></row><row><entry>2</entry><entry>100</entry></row></tbody></tgroup></table></tables>

Example 16c -- 40% Candelilla wax (Coating level=20%)

0405IR particles were prepared as follows: 1615.1g of Sodium Oxybate and 85.0g of water soluble polymer polyvinylpyrrolidone (Povidone - Plasdone^™ K30 from ISP) were solubilized in 1894.4g of absolute ethyl alcohol and 1262.9g of water. The solution was entirely sprayed onto 300g of microcrystalline cellulose spheres (Cellets^™ 127 from Pharmatrans) in a fluid bed spray coater apparatus GPCG1.1. Sodium oxybate IR particles with mean diameter of 270 microns were obtained.

0406MR coated particles were prepared as follows: 20.0g of Methacrylic acid copolymer Type C (Eudragit^™ L100-55 from Evonik), 40.0g of Methacrylic acid copolymer Type B (Eudragit^™ S100 from Evonik), 40.0g of candelilla wax (Kahlwax^™ 2039L from Brenntag), were dissolved in 904.0g of isopropanol at 78°C. The solution was sprayed entirely on 400.0g of IR particles in a fluid bed spray coater apparatus Glatt^™ G.P.C.G.1.1 with inlet temperature 48°C, spraying rate around 10.9g per min and atomization pressure 1.3 bar. MR microparticles were dried for 2 hours with inlet temperature set to 56°C. Sodium oxybate MR coated particles with mean diameter of 302 microns were obtained.

040717.0 g of MR microparticles were mixed with 0.08g of magnesium stearate (from Peter Greven). The dissolution profile of 3500mg of the mixture which corresponds to 2250mg of sodium oxybate per vessel was determined using the USP apparatus 2 in 900ml of 0.1N HCl medium and pH 6.8 phosphate buffer (0.05M monobasic potassium phosphate solution - pH adjusted to 6.8 with 5N NaOH) is given in <figref idref="f0035">Figure 69</figref> and Tables 16j and 16k. Dissolution medium temperature was maintained at 37.0 ± 0.5 °C, and the rotating paddle speed was set at 75 rpm. <tables id="tabl0106" num="0106"><table frame="all"><title>Table 16j. Dissolution profile in 0.1N HCl</title><tgroup cols="2"><colspec colnum="1" colname="col1" colwidth="26mm" align="center" /><colspec colnum="2" colname="col2" colwidth="31mm" align="center" /><thead valign="middle"><row><entry>Time (h)</entry><entry>% dissolved</entry></row></thead><tbody valign="middle"><row><entry>0</entry><entry>0</entry></row><row><entry>0,25</entry><entry>0</entry></row><row><entry>1</entry><entry>3</entry></row><row><entry>3</entry><entry>6</entry></row><row><entry>4</entry><entry>8</entry></row><row><entry>6</entry><entry>9</entry></row><row><entry>8</entry><entry>15</entry></row><row><entry>10</entry><entry>37</entry></row><row><entry>12</entry><entry>70</entry></row><row><entry>16</entry><entry>97</entry></row><row><entry>20</entry><entry>100</entry></row></tbody></tgroup></table></tables><tables id="tabl0107" num="0107"><table frame="all"><title>Table 16k. Dissolution profile in 50mM pH6.8 phosphate buffer</title><tgroup cols="2"><colspec colnum="1" colname="col1" colwidth="41mm" align="center" /><colspec colnum="2" colname="col2" colwidth="46mm" align="center" /><thead valign="middle"><row><entry>Time (h)</entry><entry>% dissolved</entry></row></thead><tbody valign="middle"><row><entry>0</entry><entry>0</entry></row><row><entry>0,25</entry><entry>24</entry></row><row><entry>0,5</entry><entry>86</entry></row><row><entry>0,75</entry><entry>99</entry></row><row><entry>1</entry><entry>100</entry></row><row><entry>2</entry><entry>100</entry></row></tbody></tgroup></table></tables>

0408The qualitative composition of 4.5g dose units comprising 50% of the dose as IR fraction and 50% of the dose as MR fraction is described in Table 161. <tables id="tabl0108" num="0108"><table frame="all"><title>Table 161</title><tgroup cols="3"><colspec colnum="1" colname="col1" colwidth="37mm" /><colspec colnum="2" colname="col2" colwidth="70mm" /><colspec colnum="3" colname="col3" colwidth="44mm" align="center" /><thead valign="top"><row><entry align="center">Component</entry><entry align="center">Function</entry><entry>Quantity per 4.5 g dose (g)</entry></row></thead><tbody><row><entry>MR microparticles</entry><entry>Modified release fraction of sodium oxybate</entry><entry>3.483</entry></row><row valign="middle"><entry>IR microparticles</entry><entry>Immediate release fraction of sodium oxybate</entry><entry>2.786</entry></row><row valign="middle"><entry>Malic acid</entry><entry>Acidifying agent</entry><entry>0.113</entry></row><row valign="middle"><entry>Xanthan gum</entry><entry>Suspending agent</entry><entry>0.050</entry></row><row valign="middle"><entry>Hydroxyethylcellulose</entry><entry>Suspending agent</entry><entry>0.075</entry></row><row valign="middle"><entry>Carrageenan gum</entry><entry>Suspending agent</entry><entry>0.075</entry></row><row><entry valign="bottom">Magnesium stearate</entry><entry>Lubricant</entry><entry>0.033</entry></row><row valign="middle"><entry>Total</entry><entry /><entry>6.615</entry></row></tbody></tgroup></table></tables>

0409The finished composition, which contains a 50:50 mixture of MR and IR particles calculated on their sodium oxybate content, was prepared as follows: 122.7g of the above IR particles, 153.2g of the above MR coated particles, 5.0g of malic acid (D/L malic acid regular from Bartek), 2.2g of xanthan gum (Xantural^™ 75 from CP Kelco), 3.3g of carragenan gum (Viscarin^™ PH209 from FMC Biopolymer), 3.3g of hydroxyethylcellulose (Natrosol^™ 250M from Ashland ) and 1.5g of magnesium stearate (from Peter Greven) were mixed in a Roue-Roehn mixer. Individual doses of 6.62g (corresponding to a 4.5g dose with half of the dose as immediate-release fraction and half of the dose as modified release fraction) were weighed.

0410<figref idref="f0035">Figures 70</figref> and Table 16m depict dissolution profiles determined using a USP apparatus 2 in 0.1N HCl. The dissolution medium was maintained at 37.0 ± 0.5°C and the rotating paddle speed was fixed at 75 rpm. Single dose units were poured in a container containing 50 mL of tap water. After 5 minutes, the suspension was poured in the dissolution vessel containing 840 mL of 0.1N HCl dissolution medium. 10 mL of water were used to rinse the container and were added to the dissolution vessel. <tables id="tabl0109" num="0109"><table frame="all"><title>Table 16m</title><tgroup cols="2"><colspec colnum="1" colname="col1" colwidth="23mm" align="center" /><colspec colnum="2" colname="col2" colwidth="41mm" align="center" /><thead valign="middle"><row><entry>Time (hour)</entry><entry>% dissolved in 0.1N HCl</entry></row></thead><tbody valign="middle"><row><entry>0</entry><entry>0</entry></row><row><entry>0,25</entry><entry>47</entry></row><row><entry>1</entry><entry>51</entry></row><row><entry>3</entry><entry>51</entry></row><row><entry>4</entry><entry>52</entry></row><row><entry>6</entry><entry>52</entry></row><row><entry>8</entry><entry>55</entry></row><row><entry>10</entry><entry>72</entry></row><row><entry>12</entry><entry>89</entry></row><row><entry>16</entry><entry>97</entry></row></tbody></tgroup></table></tables>

0411Based on the dissolution profile of the MR coated particles in pH6.8 phosphate buffer, 4.5g single dose units of the finished compositions are expected to provide the dissolution profile in pH 6.8 phosphate buffer shown in <figref idref="f0036">Figure 71</figref> and in Table 16n. <tables id="tabl0110" num="0110"><table frame="all"><title>Table 16n</title><tgroup cols="2"><colspec colnum="1" colname="col1" colwidth="18mm" align="center" /><colspec colnum="2" colname="col2" colwidth="46mm" align="center" /><thead valign="middle"><row><entry>Time (h)</entry><entry>% dissolved in pH 6.8 buffer</entry></row></thead><tbody valign="middle"><row><entry>0</entry><entry>0</entry></row><row><entry>0,25</entry><entry>62</entry></row><row><entry>0,5</entry><entry>93</entry></row><row><entry>0,75</entry><entry>99</entry></row><row><entry>1</entry><entry>100</entry></row><row><entry>2</entry><entry>100</entry></row></tbody></tgroup></table></tables>

Example 16d -- 60% Cetyl alcohol (Kolliwax

™

CA)

0412IR particles were prepared as follows: 1615.1g of Sodium Oxybate and 85.0g of water soluble polymer polyvinylpyrrolidone (Povidone - Plasdone^™ K30 from ISP) were solubilized in 1898.7g of absolute ethyl alcohol and 1262.9g of water. The solution was entirely sprayed onto 300g of microcrystalline cellulose spheres (Cellets^™ 127 from Pharmatrans) in a fluid bed spray coater apparatus GPCG1.1. Sodium oxybate IR particles with mean diameter of 272 microns were obtained.

0413MR coated particles were prepared as follows: 22.8g of methacrylic acid copolymer Type C (Eudragit^™ L100-55 from Evonik), 45.8g of Methacrylic acid copolymer Type B (Eudragit^™ S100 from Evonik), 102.9g of cetyl alcohol (Kolliwax^™ CA from BASF), were dissolved in 1472.5g of isopropanol and 77.7g of water at room temperature. The solution was sprayed entirely on 400.0g of IR particles in a fluid bed spray coater apparatus Glatt^™ G.P.C.G.1.1 with inlet temperature 48°C, spraying rate around 14.5g per min and atomization pressure 2.5 bar. Sodium oxybate MR coated particles with mean diameter of 315 microns were obtained.

041416.4 g of MR microparticles were mixed with 0.08g of magnesium stearate (from Peter Greven). The dissolution profile of 4000mg of the mixture which corresponds to 2250mg of sodium oxybate per vessel was determined using the USP apparatus 2 in 900ml of 0.1N HCl medium is given in <figref idref="f0036">Figure 72</figref> and Table 16o. Dissolution medium temperature was maintained at 37.0 ± 0.5 °C, and the rotating paddle speed was set at 75 rpm. <tables id="tabl0111" num="0111"><table frame="all"><title>Table 16o</title><tgroup cols="2"><colspec colnum="1" colname="col1" colwidth="18mm" align="center" /><colspec colnum="2" colname="col2" colwidth="41mm" align="center" /><thead valign="middle"><row><entry>Time (h)</entry><entry>% dissolved in 0.1N HCl</entry></row></thead><tbody valign="middle"><row><entry>0</entry><entry>0</entry></row><row><entry>0,25</entry><entry>13</entry></row><row><entry>1</entry><entry>84</entry></row><row><entry>3</entry><entry>103</entry></row><row><entry>4</entry><entry>103</entry></row><row><entry>6</entry><entry>103</entry></row><row><entry>8</entry><entry>103</entry></row><row><entry>10</entry><entry>104</entry></row><row><entry>12</entry><entry>104</entry></row><row><entry>16</entry><entry>103</entry></row><row><entry>20</entry><entry>102</entry></row></tbody></tgroup></table></tables>

EXAMPLE 17. EFFECT OF EUDRAGIT^™ SELECTION IN THE COATING OF THE MR MICROPARTICLES

0415Further prototypes were developed and evaluate to determine the effect of the Eudragit^™ selected on the dissolution of the MR microparticles.

Example 17a -- 100% Eudragit

™

S100

0416IR particles were prepared as follows: 1615.0g of Sodium Oxybate and 85.0g of water soluble polymer polyvinylpyrrolidone (Povidone - Plasdone^™ K30 from ISP) were solubilized in 1894.3g of absolute ethyl alcohol and 1262.9g of water. The solution was entirely sprayed onto 300g of microcrystalline cellulose spheres (Cellets^™ 127 from Pharmatrans) in a fluid bed spray coater apparatus GPCG1.1. Sodium oxybate IR particles with mean diameter of 285 microns were obtained.

0417Sodium oxybate IR seal-coated particles were prepared by coating the IR particles described above with a seal-coat layer: 170.0g of hydroxypropylcellulose (Klucel^™ EF Pharm from Hercules) were solubilized in 4080.0g of acetone. The solution was entirely sprayed onto 1530.0g of the above IR particles in a fluid bed spray coater apparatus. Sodium oxybate IR particles with volume mean diameter of about 298 microns were obtained.

0418MR coated particles were prepared as follows: 100.0g of Methacrylic acid copolymer Type B (Eudragit^™ S100 from Evonik), 150.0g of Hydrogenated cottonseed oil (Lubritab^™ from JRS), were dissolved in 2250.0g of isopropanol at 78°C. The solution was sprayed entirely on 750.0g of the above IR particles in a fluid bed spray coater apparatus Glatt^™ G.P.C.G.1.1 with inlet temperature 48°C, spraying rate around 12.0g per min and atomization pressure 1.6 bar. MR microparticles were dried for 2 hours with inlet temperature set to 56°C. Sodium oxybate MR coated particles with mean diameter of 307 microns were obtained.

0419The dissolution profile of 2100mg of the mixture which corresponds to 1253mg of sodium oxybate per vessel was determined using the USP apparatus 2 in 500ml of 0.1N HCl medium is reported in <figref idref="f0037">Figure 73</figref> and Table 17a. Dissolution medium temperature was maintained at 37.0 ± 0.5 °C, and the rotating paddle speed was set at 100 rpm. <tables id="tabl0112" num="0112"><table frame="all"><title>Table 17a</title><tgroup cols="2"><colspec colnum="1" colname="col1" colwidth="19mm" align="center" /><colspec colnum="2" colname="col2" colwidth="24mm" align="center" /><thead valign="middle"><row><entry>Time (h)</entry><entry>% dissolved</entry></row></thead><tbody valign="middle"><row><entry>0</entry><entry>0</entry></row><row><entry>0,25</entry><entry>0</entry></row><row><entry>1</entry><entry>1</entry></row><row><entry>3</entry><entry>3</entry></row><row><entry>4</entry><entry>4</entry></row><row><entry>6</entry><entry>9</entry></row><row><entry>8</entry><entry>30</entry></row><row><entry>10</entry><entry>60</entry></row><row><entry>12</entry><entry>81</entry></row><row><entry>16</entry><entry>92</entry></row></tbody></tgroup></table></tables>

0420The finished composition, which contains a 50:50 mixture of MR and IR particles calculated on their sodium oxybate content, was prepared as follows: 425.0g of the above IR seal-coated particles, 510.0g of the above MR coated particles, 30.9g of malic acid (D/L malic acid regular from Bartek), 4.9g of xanthan gum (Xantural^™ 180 from CP Kelco), 4.9g of Aerosil^™ 200 (amorphous anhydrous colloidal silicon dioxide from Evonik) and 9.9g of magnesium stearate (from Peter Greven) were mixed in a Roue-Roehn mixer. Individual doses of 7.18g (corresponding to a 4.5g dose with half of the dose as immediate-release fraction and half of the dose as modified release fraction) were weighed.

0421<figref idref="f0037">Figure 74</figref> and Table 17b below depict dissolution profiles determined using a USP apparatus 2 in 0.1N HCl. The dissolution medium was maintained at 37.0 ± 0.5°C and the rotating paddle speed was fixed at 100 rpm. Single dose units were poured in a container containing 50 mL of tap water. After 5 minutes, the suspension was poured in the dissolution vessel containing 840 mL of 0.1N HCl dissolution medium. 10 mL of water were used to rinse the container and were added to the dissolution vessel. <tables id="tabl0113" num="0113"><table frame="all"><title>Table 17b</title><tgroup cols="2"><colspec colnum="1" colname="col1" colwidth="23mm" align="center" /><colspec colnum="2" colname="col2" colwidth="41mm" align="center" /><thead valign="middle"><row><entry>Time (hour)</entry><entry>% dissolved in 0.1N HCl</entry></row></thead><tbody valign="middle"><row><entry>0</entry><entry>0</entry></row><row><entry>0,25</entry><entry>50</entry></row><row><entry>1</entry><entry>50</entry></row><row><entry>3</entry><entry>50</entry></row><row><entry>4</entry><entry>51</entry></row><row><entry>6</entry><entry>55</entry></row><row><entry>8</entry><entry>67</entry></row><row><entry>10</entry><entry>84</entry></row><row><entry>12</entry><entry>91</entry></row><row><entry>16</entry><entry>94</entry></row></tbody></tgroup></table></tables>

0422<figref idref="f0038">Figure 75</figref> and Table 17c depict the dissolution profile determined using a USP apparatus 2 in phosphate buffer pH 6.8 (0.05M monobasic potassium phosphate solution - pH adjusted to 6.8 with 5N NaOH). The dissolution medium was maintained at 37.0 ± 0.5°C and the rotating paddle speed was fixed at 100 rpm. Single dose units were poured in a container containing 50 mL of tap water. After 5 minutes, the suspension was poured in the dissolution vessel containing 840 mL of pH 6.8 dissolution medium. 10 mL of water were used to rinse the container and were added to the dissolution vessel. <tables id="tabl0114" num="0114"><table frame="all"><title>Table 17c</title><tgroup cols="2"><colspec colnum="1" colname="col1" colwidth="23mm" align="center" /><colspec colnum="2" colname="col2" colwidth="23mm" align="center" /><thead valign="middle"><row><entry>Time (hour)</entry><entry>% dissolved</entry></row></thead><tbody valign="middle"><row><entry>0</entry><entry>0</entry></row><row><entry>0,25</entry><entry>50</entry></row><row><entry>1</entry><entry>51</entry></row><row><entry>3</entry><entry>54</entry></row><row><entry>4</entry><entry>56</entry></row><row><entry>6</entry><entry>93</entry></row><row><entry>8</entry><entry>99</entry></row><row><entry>10</entry><entry>100</entry></row><row><entry>12</entry><entry>100</entry></row><row><entry>16</entry><entry>97</entry></row></tbody></tgroup></table></tables>

Example 17b -- 100% Eudragit

™

L100-55

0423IR particles were prepared as follows: 1615.0g of Sodium Oxybate and 85.1g of water soluble polymer polyvinylpyrrolidone (Povidone - Plasdone^™ K30 from ISP) were solubilized in 1896.2g of absolute ethyl alcohol and 1264.4g of water. The solution was entirely sprayed onto 300g of microcrystalline cellulose spheres (Cellets^™ 127 from Pharmatrans) in a fluid bed spray coater apparatus GPCG1.1. Sodium oxybate IR particles with mean diameter of 275 microns were obtained.

0424MR coated particles were prepared as follows: 68.7g of Methacrylic acid copolymer Type C (Eudragit^™ L100-55 from Evonik), 102.9g of hydrogenated cottonseed oil (Lubritab^™ from JRS), were dissolved in 1543.2g of isopropanol at 78°C. The solution was sprayed entirely on 400.0g of IR particles in a fluid bed spray coater apparatus Glatt^™ G.P.C.G.1.1 with inlet temperature 46°C, spraying rate around 12.7g per min and atomization pressure 1.3 bar. MR microparticles were dried for 2 hours with inlet temperature set to 56°C. Sodium oxybate MR coated particles with mean diameter of 328 microns were obtained.

042517.0 g of MR microparticles were mixed with 0.09g of magnesium stearate (from Peter Greven). The dissolution profile in of 4000mg of the mixture which corresponds to 2250mg of sodium oxybate per vessel was determined using the USP apparatus 2 in 900ml of 0.1N HCl medium and in pH 6.8 phosphate buffer (0.05M monobasic potassium phosphate solution - pH adjusted to 6.8 with 5N NaOH) is given in <figref idref="f0038">Figure 76</figref> and Tables 17d and 17e. Dissolution medium temperature was maintained at 37.0 ± 0.5 °C, and the rotating paddle speed was set at 100 rpm. <tables id="tabl0115" num="0115"><table frame="all"><title>Table 17d. Dissolution profile in 0.1N HCl</title><tgroup cols="2"><colspec colnum="1" colname="col1" colwidth="26mm" align="center" /><colspec colnum="2" colname="col2" colwidth="31mm" align="center" /><thead valign="middle"><row><entry>Time (h)</entry><entry>% dissolved</entry></row></thead><tbody valign="middle"><row><entry>0</entry><entry>0</entry></row><row><entry>0,25</entry><entry>0</entry></row><row><entry>1</entry><entry>2</entry></row><row><entry>3</entry><entry>3</entry></row><row><entry>4</entry><entry>6</entry></row><row><entry>6</entry><entry>53</entry></row><row><entry>8</entry><entry>95</entry></row><row><entry>10</entry><entry>99</entry></row><row><entry>12</entry><entry>99</entry></row><row><entry>16</entry><entry>99</entry></row><row><entry>20</entry><entry>99</entry></row></tbody></tgroup></table></tables><tables id="tabl0116" num="0116"><table frame="all"><title>Table 17e.Dissolution profile in 50mM pH6.8 phosphate buffer</title><tgroup cols="2"><colspec colnum="1" colname="col1" colwidth="41mm" align="center" /><colspec colnum="2" colname="col2" colwidth="46mm" align="center" /><thead valign="middle"><row><entry>Time (h)</entry><entry>% dissolved</entry></row></thead><tbody valign="middle"><row><entry>0</entry><entry>0</entry></row><row><entry>0,25</entry><entry>21</entry></row><row><entry>0,5</entry><entry>99</entry></row><row><entry>0,75</entry><entry>103</entry></row><row><entry>1</entry><entry>103</entry></row><row><entry>2</entry><entry>103</entry></row></tbody></tgroup></table></tables>

0426The finished composition, which contains a 50:50 mixture of MR and IR particles calculated on their sodium oxybate content, was prepared as follows: 153.3g of the above IR particles, 219.0g of the above MR coated particles, 6.2g of malic acid (D/L malic acid regular from Bartek), 2.8g of xanthan gum (Xantural^™ 75 from CP Kelco), 4.1g of carragenan gum (Viscarin^™ PH209 from FMC Biopolymer), 4.1g of hydroxyethylcellulose (Natrosol^™ 250M from Ashland ) and 1.9g of magnesium stearate (from Peter Greven) were mixed in a Roue-Roehn mixer. Individual doses of 7.12g (corresponding to a 4.5g dose with half of the dose as immediate-release fraction and half of the dose as modified release fraction) were weighed.

0427<figref idref="f0039">Figure 77</figref> and Table 17f depict dissolution profiles determined using a USP apparatus 2 in 0.1N HCl. The dissolution medium was maintained at 37.0 ± 0.5°C and the rotating paddle speed was fixed at 75 rpm. Single dose units were poured in a container containing 50 mL of tap water. After 5 minutes, the suspension was poured in the dissolution vessel containing 840 mL of 0.1N HCl dissolution medium. 10 mL of water were used to rinse the container and were added to the dissolution vessel. <tables id="tabl0117" num="0117"><table frame="all"><title>Table 17f</title><tgroup cols="2"><colspec colnum="1" colname="col1" colwidth="23mm" align="center" /><colspec colnum="2" colname="col2" colwidth="23mm" align="center" /><thead valign="middle"><row><entry>Time (hour)</entry><entry>% dissolved</entry></row></thead><tbody valign="middle"><row><entry>0</entry><entry>0</entry></row><row><entry>0,25</entry><entry>46</entry></row><row><entry>1</entry><entry>51</entry></row><row><entry>3</entry><entry>52</entry></row><row><entry>4</entry><entry>59</entry></row><row><entry>6</entry><entry>94</entry></row><row><entry>8</entry><entry>98</entry></row><row><entry>10</entry><entry>98</entry></row><row><entry>12</entry><entry>98</entry></row><row><entry>16</entry><entry>98</entry></row></tbody></tgroup></table></tables>

0428Based on the dissolution profile of the MR coated particles in pH6.8 phosphate buffer, 4.5g single dose units of the finished compositions are expected to provide the dissolution profile in pH 6.8 phosphate buffer in <figref idref="f0039">Figure 78</figref> and Table 17g. <tables id="tabl0118" num="0118"><table frame="all"><title>Table 17g</title><tgroup cols="2"><colspec colnum="1" colname="col1" colwidth="18mm" align="center" /><colspec colnum="2" colname="col2" colwidth="46mm" align="center" /><thead valign="middle"><row><entry>Time (h)</entry><entry>% dissolved in pH 6.8 buffer</entry></row></thead><tbody valign="middle"><row><entry>0</entry><entry>0</entry></row><row><entry>0,25</entry><entry>61</entry></row><row><entry>0,5</entry><entry>99</entry></row><row><entry>0,75</entry><entry>101</entry></row><row><entry>1</entry><entry>101</entry></row><row><entry>2</entry><entry>101</entry></row></tbody></tgroup></table></tables>

Example 17c -- Mixture Eudragit

™

L100-S100 (50-50)

0429IR particles were prepared as follows: 1615.0g of Sodium Oxybate and 85.0g of water soluble polymer polyvinylpyrrolidone (Povidone - Plasdone^™ K30 from ISP) were solubilized in 1903.2g of absolute ethyl alcohol and 1267.1g of water. The solution was entirely sprayed onto 300g of microcrystalline cellulose spheres (Cellets^™ 127 from Pharmatrans) in a fluid bed spray coater apparatus GPCG1.1. Sodium oxybate IR particles with mean diameter of 268 microns were obtained.

0430MR coated particles were prepared as follows: 34.3g of Methacrylic acid copolymer Type A (Eudragit^™ L100 from Evonik), 34.3g of Methacrylic acid copolymer Type B (Eudragit^™ S100 from Evonik), 102.9g of Hydrogenated cottonseed oil (Lubritab^™ from JRS), were dissolved in 1543.0g of isopropanol at 78°C. The solution was sprayed entirely on 400.0g of IR particles in a fluid bed spray coater apparatus Glatt^™ G.P.C.G.1.1 with inlet temperature 48°C, spraying rate around 11.8g per min and atomization pressure 1.3 bar. MR microparticles were dried for 2 hours with inlet temperature set to 56°C. Sodium oxybate MR coated particles with mean diameter of 316 microns were obtained.

043124.0 g of MR microparticles were mixed with 0.12g of magnesium stearate (from Peter Greven). The dissolution profile of 4050mg of the mixture which corresponds to 2280mg of sodium oxybate per vessel was determined using the USP apparatus 2 in 900ml of 0.1N HCl medium and in pH 6.8 phosphate buffer (0.05M monobasic potassium phosphate solution - pH adjusted to 6.8 with 5N NaOH) is given in <figref idref="f0040">Figure 79</figref> and Tables 17h and 17i. Dissolution medium temperature was maintained at 37.0 ± 0.5 °C, and the rotating paddle speed was set at 100 rpm. <tables id="tabl0119" num="0119"><table frame="all"><title>Table 17h. Dissolution profile in 0.1N HCl</title><tgroup cols="2"><colspec colnum="1" colname="col1" colwidth="26mm" align="center" /><colspec colnum="2" colname="col2" colwidth="31mm" align="center" /><thead valign="middle"><row><entry>Time (h)</entry><entry>% dissolved</entry></row></thead><tbody valign="middle"><row><entry>0</entry><entry>0</entry></row><row><entry>0,25</entry><entry>0</entry></row><row><entry>1</entry><entry>2</entry></row><row><entry>3</entry><entry>2</entry></row><row><entry>4</entry><entry>3</entry></row><row><entry>6</entry><entry>7</entry></row><row><entry>8</entry><entry>31</entry></row><row><entry>10</entry><entry>62</entry></row><row><entry>12</entry><entry>83</entry></row><row><entry>16</entry><entry>98</entry></row><row><entry>20</entry><entry>100</entry></row></tbody></tgroup></table></tables><tables id="tabl0120" num="0120"><table frame="all"><title>Table 17i. Dissolution profile in 50mM pH6.8 phosphate buffer</title><tgroup cols="2"><colspec colnum="1" colname="col1" colwidth="41mm" align="center" /><colspec colnum="2" colname="col2" colwidth="46mm" align="center" /><thead valign="middle"><row><entry>Time (h)</entry><entry>% dissolved</entry></row></thead><tbody valign="middle"><row><entry>0</entry><entry>0</entry></row><row><entry>0,25</entry><entry>2</entry></row><row><entry>0,5</entry><entry>5</entry></row><row><entry>0,75</entry><entry>13</entry></row><row><entry>1</entry><entry>47</entry></row><row><entry>2</entry><entry>101</entry></row></tbody></tgroup></table></tables>

0432The finished composition, which contains a 50:50 mixture of MR and IR particles calculated on their sodium oxybate content, was prepared as follows: 223.0g of the above IR particles, 318.4g of the above MR coated particles, 11.2g of malic acid (D/L malic acid regular from Bartek), 4.0g of xanthan gum (Xantural^™ 75 from CP Kelco), 6.0g of carragenan gum (Viscarin^™ PH209 from FMC Biopolymer), 6.0g of hydroxyethylcellulose (Natrosol^™ 250M from Ashland ) and 2.9g of magnesium stearate (from Peter Greven) were mixed in a Roue-Roehn mixer. Individual doses of 7.14g (corresponding to a 4.5g dose with half of the dose as immediate-release fraction and half of the dose as modified release fraction) were weighed.

0433<figref idref="f0040">Figure 80</figref> and Table 17j depict dissolution profiles determined using a USP apparatus 2 in 0.1N HCl. The dissolution medium was maintained at 37.0 ± 0.5°C and the rotating paddle speed was fixed at 75 rpm. Single dose units were poured in a container containing 50 mL of tap water. After 5 minutes, the suspension was poured in the dissolution vessel containing 840 mL of 0.1N HCl dissolution medium. 10 mL of water were used to rinse the container and were added to the dissolution vessel. <tables id="tabl0121" num="0121"><table frame="all"><title>Table 17j</title><tgroup cols="2"><colspec colnum="1" colname="col1" colwidth="23mm" align="center" /><colspec colnum="2" colname="col2" colwidth="23mm" align="center" /><thead valign="middle"><row><entry>Time (hour)</entry><entry>% dissolved</entry></row></thead><tbody valign="middle"><row><entry>0</entry><entry>0</entry></row><row><entry>0,25</entry><entry>47</entry></row><row><entry>1</entry><entry>51</entry></row><row><entry>3</entry><entry>51</entry></row><row><entry>6</entry><entry>59</entry></row><row><entry>8</entry><entry>80</entry></row><row><entry>10</entry><entry>92</entry></row><row><entry>12</entry><entry>96</entry></row><row><entry>16</entry><entry>97</entry></row></tbody></tgroup></table></tables>

0434Based on the dissolution profile of the MR coated particles in pH6.8 phosphate buffer, 4.5g single dose units of the finished composition are expected to have the dissolution profile in pH 6.8 phosphate buffer given in <figref idref="f0041">Figure 81</figref> and Table 17k. <tables id="tabl0122" num="0122"><table frame="all"><title>Table 17k</title><tgroup cols="2"><colspec colnum="1" colname="col1" colwidth="18mm" align="center" /><colspec colnum="2" colname="col2" colwidth="46mm" align="center" /><thead valign="middle"><row><entry>Time (h)</entry><entry>% dissolved in pH 6.8 buffer</entry></row></thead><tbody valign="middle"><row><entry>0</entry><entry>0</entry></row><row><entry>0,25</entry><entry>51</entry></row><row><entry>0,5</entry><entry>53</entry></row><row><entry>0,75</entry><entry>56</entry></row><row><entry>1</entry><entry>73</entry></row><row><entry>2</entry><entry>100</entry></row></tbody></tgroup></table></tables>

EXAMPLE 18. IN VIVO PHARMACOKINETIC STUDY OF FINISHED COMPOSITION ACCORDING TO EXAMPLE 1 (DOSE ESCALATING STUDY)

0435Pharmacokinetic testing was undertaken in vivo in healthy human volunteers. Pharmacokinetic parameters were normalized by the dose. To assess the dose-proportionality, log-transformed dose-normalized PK parameters were pairwise compared according to the statistical methodology described in <nplcit id="ncit0008" npl-type="s"><text>FDA's 2013 Draft Guidance entitled BIOEQUIVALENCE STUDIES WITH PHARMACOKINETIC ENDPOINTS FOR DRUGS SUBMITTED UNDER AN ANDA (2013</text></nplcit>). All testing was performed in subjects two hours after eating a standardized dinner. A test product with finished composition of Example 1 and manufactured at larger scale was administered in sequential ascending doses, 4.5g, 7.5g and 9g, one week apart. The tested samples were manufactured as described in Table 1c for 4.5g and quantities were homothetically adjusted for the other strengths. The dissolution profiles of the MR portions of the test product are presented in <figref idref="f0043">Figures 86</figref> and <figref idref="f0044">87</figref>. The dissolution profiles of the test product are presented in <figref idref="f0044">Figures 88</figref> and <figref idref="f0045">89</figref>. The individual concentrations of gamma-hydroxybutyrate and derived PK parameters are summarized below (Tables 18a and 18b) and in <figref idref="f0046">Figure 90</figref>. <tables id="tabl0123" num="0123"><table frame="all"><title>Table 18a.Pharmacokinetic Parameters of 4.5g, 7.5g, and 9g</title><tgroup cols="6"><colspec colnum="1" colname="col1" colwidth="30mm" align="center" /><colspec colnum="2" colname="col2" colwidth="25mm" align="center" /><colspec colnum="3" colname="col3" colwidth="27mm" align="center" /><colspec colnum="4" colname="col4" colwidth="27mm" align="center" /><colspec colnum="5" colname="col5" colwidth="29mm" align="center" /><colspec colnum="6" colname="col6" colwidth="25mm" align="center" /><thead valign="top"><row><entry>Finished composition of test product</entry><entry>Mean C_max (µg/mL) (% CV)</entry><entry>Mean AUC_inf (µg/mL*h) (% CV)</entry><entry>Mean AUC_8h (µg/mL*h) (% CV)</entry><entry>Median T_max (hour) (min-max)</entry><entry>Mean C_8h (µg/mL) (% CV)</entry></row></thead><tbody valign="middle"><row><entry>4.5g</entry><entry>42.9 (37)</entry><entry>191 (50)</entry><entry>174 (55)</entry><entry>1.71 (0.333-4)</entry><entry>4.76 (105)</entry></row><row><entry>7.5g</entry><entry>72.0 (32)</entry><entry>357 (48)</entry><entry>320 (46)</entry><entry>1.5 (0.333-7)</entry><entry>19.7 (101)</entry></row><row><entry>9.0g</entry><entry>84.5 (34)</entry><entry>443 (46)</entry><entry>379 (41)</entry><entry>2 (0.5-4)</entry><entry>25.5 (97)</entry></row></tbody></tgroup></table></tables>

0436AUC and C_max values increased more than dose-proportionally with increasing doses of gamma-hydroxybutyrate formulated as the test product. <tables id="tabl0124" num="0124"><table frame="all"><title>Table 18b. Mean plasma concentration of gamma-hydroxybutyrate (microgram/mL) versus time of finished composition of test product</title><tgroup cols="4"><colspec colnum="1" colname="col1" colwidth="17mm" align="center" /><colspec colnum="2" colname="col2" colwidth="49mm" align="center" /><colspec colnum="3" colname="col3" colwidth="49mm" align="center" /><colspec colnum="4" colname="col4" colwidth="48mm" align="center" /><thead valign="top"><row><entry>Time (hr)</entry><entry>Test product 4.5g (2 h after meal) (N=20)</entry><entry>Test product 7.5g (2 h after meal) (N=20)</entry><entry>Test product 9g (2 h after meal) (N=12)</entry></row></thead><tbody><row><entry>0</entry><entry>0.00</entry><entry>0.00</entry><entry>0.00</entry></row><row><entry>0.167</entry><entry>12.5</entry><entry>17.7</entry><entry>9.34</entry></row><row><entry>0.333</entry><entry>23.4</entry><entry>39.0</entry><entry>32.7</entry></row><row><entry>0.5</entry><entry>28.1</entry><entry>48.4</entry><entry>47.5</entry></row><row><entry>1</entry><entry>34.7</entry><entry>59.8</entry><entry>60.9</entry></row><row><entry>1.5</entry><entry>36.7</entry><entry>63.8</entry><entry>71.6</entry></row><row><entry>2</entry><entry>35.7</entry><entry>61.6</entry><entry>79.3</entry></row><row><entry>2.5</entry><entry>34.7</entry><entry>56.0</entry><entry>64.9</entry></row><row><entry>3</entry><entry>29.8</entry><entry>50.1</entry><entry>65.3</entry></row><row><entry>3.5</entry><entry>26.9</entry><entry>46.0</entry><entry>60.0</entry></row><row><entry>4</entry><entry>23.5</entry><entry>40.9</entry><entry>60.8</entry></row><row><entry>4.5</entry><entry>20.1</entry><entry>36.6</entry><entry>48.8</entry></row><row><entry>5</entry><entry>17.3</entry><entry>32.7</entry><entry>45.3</entry></row><row><entry>5.5</entry><entry>15.4</entry><entry>30.8</entry><entry>41.3</entry></row><row><entry>6</entry><entry>13.4</entry><entry>28.7</entry><entry>37.6</entry></row><row><entry>7</entry><entry>9.66</entry><entry>24.7</entry><entry>30.5</entry></row><row><entry>8</entry><entry>4.76</entry><entry>19.7</entry><entry>25.5</entry></row><row><entry>10</entry><entry>0.727</entry><entry>6.97</entry><entry>13.0</entry></row><row><entry>12</entry><entry>0.211</entry><entry>1.35</entry><entry>5.13</entry></row><row><entry>14</entry><entry>NC</entry><entry>0.392</entry><entry>0.820</entry></row></tbody></tgroup><tgroup cols="4" rowsep="0"><colspec colnum="1" colname="col1" colwidth="17mm" align="justify" /><colspec colnum="2" colname="col2" colwidth="49mm" /><colspec colnum="3" colname="col3" colwidth="49mm" /><colspec colnum="4" colname="col4" colwidth="48mm" /><tbody><row><entry namest="col1" nameend="col4">NC: Not Calculated</entry></row></tbody></tgroup></table></tables>

0437Table 18c compares the pharmacokinetic parameters AUC_inf and C_8h obtained for 4.5g of the test product to the same parameters calculated 2 x 2.25g, i.e. 4.5 g total dose of Xyrem^®. <tables id="tabl0125" num="0125"><table frame="all"><title>Table 18c.Comparison to 4.5 g divided dose of Xyrem^®</title><tgroup cols="5"><colspec colnum="1" colname="col1" colwidth="32mm" align="center" /><colspec colnum="2" colname="col2" colwidth="26mm" align="center" /><colspec colnum="3" colname="col3" colwidth="37mm" align="center" /><colspec colnum="4" colname="col4" colwidth="29mm" align="center" /><colspec colnum="5" colname="col5" colwidth="39mm" align="center" /><thead valign="middle"><row><entry /><entry>Mean C_8h (µg/mL)</entry><entry>Ratio (%) C_8h composition to C_8h Xyrem^®</entry><entry>Mean AUC_inf (µg/mL*h)</entry><entry>Ratio (%) AUC_inf composition to AUC_inf Xyrem^®</entry></row></thead><tbody valign="middle"><row><entry>Xyrem^® 2 x 2.25 g *</entry><entry>9.24</entry><entry>NA</entry><entry>214</entry><entry>NA</entry></row><row><entry>Test product 4.5 g</entry><entry>4.76</entry><entry>52%</entry><entry>191</entry><entry>89%</entry></row></tbody></tgroup><tgroup cols="5" rowsep="0"><colspec colnum="1" colname="col1" colwidth="32mm" align="justify" /><colspec colnum="2" colname="col2" colwidth="26mm" /><colspec colnum="3" colname="col3" colwidth="37mm" /><colspec colnum="4" colname="col4" colwidth="29mm" /><colspec colnum="5" colname="col5" colwidth="39mm" /><tbody><row><entry namest="col1" nameend="col5">*data from the pilot PK study of example 3</entry></row></tbody></tgroup></table></tables>

0438Table 18d compares the pharmacokinetic parameters AUC_inf and C_8h obtained for 7.5g of the test product to the same parameters calculated 2 x 3.75 g, i.e. 7.5g total dose of Xyrem^®. <tables id="tabl0126" num="0126"><table frame="all"><title>Table 18d. Comparison to 7.5 g divided dose of Xyrem^®</title><tgroup cols="5"><colspec colnum="1" colname="col1" colwidth="73mm" align="center" /><colspec colnum="2" colname="col2" colwidth="18mm" align="center" /><colspec colnum="3" colname="col3" colwidth="25mm" align="center" /><colspec colnum="4" colname="col4" colwidth="21mm" align="center" /><colspec colnum="5" colname="col5" colwidth="26mm" align="center" /><thead valign="middle"><row><entry /><entry>Mean C_8h (µg/mL)</entry><entry>Ratio (%) C_8h composition to C_8h Xyrem^®</entry><entry>Mean AUC_inf (µg/mL*h)</entry><entry>Ratio (%) AUC_inf composition to AUC_inf Xyrem^®</entry></row></thead><tbody valign="middle"><row><entry>Xyrem^® 2 x 3.75 g (extrapolation from 2 x 4.5 g *)</entry><entry>24.1</entry><entry>NA</entry><entry>432</entry><entry>NA</entry></row><row><entry>Test product 7.5g</entry><entry>19.7</entry><entry>82%</entry><entry>357</entry><entry>83%</entry></row></tbody></tgroup><tgroup cols="5" rowsep="0"><colspec colnum="1" colname="col1" colwidth="73mm" align="justify" /><colspec colnum="2" colname="col2" colwidth="18mm" /><colspec colnum="3" colname="col3" colwidth="25mm" /><colspec colnum="4" colname="col4" colwidth="21mm" /><colspec colnum="5" colname="col5" colwidth="26mm" /><tbody><row><entry namest="col1" nameend="col5">* based on data from NDA #21-196</entry></row></tbody></tgroup></table></tables>

0439Table 18e compares the pharmacokinetic parameters AUC_inf and C_8h obtained for 7.5 g and 9 g of the test product to the same parameters calculated for 2 x 4.5g, i.e. 9g total dose of Xyrem^®. <tables id="tabl0127" num="0127"><table frame="all"><title>Table 18e.Comparison to 9 g divided dose of Xyrem^®</title><tgroup cols="5"><colspec colnum="1" colname="col1" colwidth="30mm" align="center" /><colspec colnum="2" colname="col2" colwidth="26mm" align="center" /><colspec colnum="3" colname="col3" colwidth="37mm" align="center" /><colspec colnum="4" colname="col4" colwidth="29mm" align="center" /><colspec colnum="5" colname="col5" colwidth="40mm" align="center" /><thead valign="middle"><row><entry /><entry>Mean C_8h (µg/mL)</entry><entry>Ratio (%) C_8h composition to C_8h Xyrem^®</entry><entry>Mean AUC_inf (µg/mL*h)</entry><entry>Ratio (%) AUC_inf composition to AUC_inf Xyrem^®</entry></row></thead><tbody valign="middle"><row><entry>Xyrem^® 2 x 4.5 g *</entry><entry>28.9</entry><entry>NA</entry><entry>518</entry><entry>NA</entry></row><row><entry>Test product 7.5g</entry><entry>19.7</entry><entry>68%</entry><entry>357</entry><entry>69%</entry></row><row><entry>Test product 9g</entry><entry>25.5</entry><entry>88%</entry><entry>443</entry><entry>86%</entry></row></tbody></tgroup><tgroup cols="5" rowsep="0"><colspec colnum="1" colname="col1" colwidth="30mm" align="justify" /><colspec colnum="2" colname="col2" colwidth="26mm" /><colspec colnum="3" colname="col3" colwidth="37mm" /><colspec colnum="4" colname="col4" colwidth="29mm" /><colspec colnum="5" colname="col5" colwidth="40mm" /><tbody><row><entry namest="col1" nameend="col5">*data from NDA #21-196</entry></row></tbody></tgroup></table></tables>

0440For the finished composition administered at 4.5g, mean C_6h, mean C_7h are greater than, and mean C_10h are less than, the mean C_4h of the dose of Xyrem^®. In addition, the ratio C_3h/C_max(Xyrem^®) is 1.03. The ratio C_4h/C_max(Xyrem^®) is 0.81. The ratio C_4.5h/C_max(Xyrem^®) is 0.69.

0441For the finished composition administered at 7.5g, mean C_6h, mean C_7h are greater than, and mean C_10h are less than, the mean C_4h of the dose of Xyrem^®. In addition, the ratio C_3h/C_max(Xyrem^®) is 0.77. The ratio C_4h/C_max(Xyrem^®) is 0.63. The ratio C_4.5h/C_max(Xyrem^®) is 0.57.

0442For the finished composition administered at 9g, mean C_6h, mean C_7h are greater than, and mean C_10h are less than, the mean C_4h of the dose of Xyrem^®. In addition, the ratio C_3h/C_max(Xyrem^®) is 0.84. The ratio C_4h/C_max(Xyrem^®) is 0.78. The ratio C_4.5h/C_max(Xyrem^®) is 0.63.

0443For the finished composition administered at 7.5g compared to Xyrem^® at 2 x 4.5 g, i.e. total dose of 9 g, the ratio C_3h/C_max(Xyrem^®) is 0.65. The ratio C_4h/C_max(Xyrem^®) is 0.53. The ratio C_4.5h/C_max(Xyrem^®) is 0.47.

0444Throughout this application, various publications are referenced. The disclosures of these publications in their entireties are hereby incorporated by reference into this application in order to more fully describe the state of the art to which this invention pertains. It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the scope or spirit of the invention. Other embodiments of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the invention being indicated by the following claims.

0445The present invention may also be described or defined in accordance with the following clauses: <ol id="ol0015"><li>1. A modified release formulation of gamma-hydroxybutyrate, comprising immediate release and modified release portions, wherein: <ol id="ol0016" compact="compact"><li>a) the formulation releases at least 80% of its gamma-hydroxybutyrate at 3 hours when tested in a dissolution apparatus 2 according to USP 38 <711> in 900 mL of 0.05M monobasic potassium phosphate buffer pH 6.8 at a temperature of 37° C and a paddle speed of 75 rpm,</li><li>b) the formulation releases 10% to 65% of its gamma-hydroxybutyrate at one hour and at three hours when tested in a dissolution apparatus 2 according to USP 38 <711> in 900 mL of 0.1N hydrochloric acid at a temperature of 37°C and a paddle speed of 75 rpm,</li><li>c) the formulation releases greater than 60% of its gamma-hydroxybutyrate at 10 hours when tested in a dissolution apparatus 2 according to USP 38 <711> in 900 mL of 0.1N hydrochloric acid at a temperature of 37°C and a paddle speed of 75 rpm, and</li><li>d) the modified release portion releases greater than 80% of its gamma-hydroxybutyrate at 3 hours in a dissolution test started in 750 mL of 0.1 N hydrochloric acid for 2 hours then switched to 950 mL 0.05M monobasic potassium phosphate buffer adjusted to pH 6.8 at a temperature of 37°C and a paddle speed of 75 rpm.</li></ol></li><li>2. A modified release formulation of gamma-hydroxybutyrate, wherein a 7.5 g dose of the formulation has been shown to achieve a mean AUC_inf of greater than 340hr•microgram/mL.</li><li>3. A modified release formulation of gamma-hydroxybutyrate, wherein a 7.5 g dose of the formulation has been shown to achieve a mean AUC_inf of greater than 340 hr•microgram/mL, and a mean C_8h that is from 50% to 130% of the mean C_8h provided by an equal dose of immediate release liquid solution of sodium oxybate administered at t₀ and t_4h in equally divided doses approximately two hours after a standardized evening meal.</li><li>4. A modified release formulation of gamma-hydroxybutyrate, wherein the formulation releases (a) at least 80% of its gamma-hydroxybutyrate at three hours when tested in a dissolution apparatus 2 according to USP 38 <711> in 900 mL of 0.05M monobasic potassium phosphate buffer pH 6.8 at a temperature of 37° C and a paddle speed of 75 rpm, and (b) from 10% to 65%, of its gamma-hydroxybutyrate at one hour and three hours when tested in a dissolution apparatus 2 according to USP 38 <711> in 900 mL of 0.1N hydrochloric acid at a temperature of 37°C and a paddle speed of 75 rpm.</li><li>5. A modified release formulation of gamma-hydroxybutyrate comprising immediate release and modified release portions, wherein: <ol id="ol0017" compact="compact"><li>a) the formulation releases at least 80% of its gamma-hydroxybutyrate at 3 hours when tested in a dissolution apparatus 2 according to USP 38 <711> in 900 mL of 0.05M monobasic potassium phosphate buffer pH 6.8 at a temperature of 37° C and a paddle speed of 75 rpm,</li><li>b) the formulation releases from 10% to 65%, of its gamma-hydroxybutyrate at one hour and three hours when tested in a dissolution apparatus 2 according to USP 38 <711> in 900 mL of 0.1N hydrochloric acid at a temperature of 37°C and a paddle speed of 75 rpm, and</li><li>c) the modified release portion releases greater than 80% of its gamma-hydroxybutyrate at 3 hours in a dissolution test started in 750 mL of 0.1N hydrochloric acid for 2 hours then switched to 950 mL 0.05M monobasic potassium phosphate buffer adjusted to pH 6.8 at a temperature of 37°C and a paddle speed of 75 rpm.</li></ol></li><li>6. A modified release formulation of gamma-hydroxybutyrate, comprising immediate release and modified release portions, wherein <ol id="ol0018" compact="compact"><li>a) a 7.5 g dose of the formulation has been shown to achieve a mean AUC_inf of greater than 340 hr•microgram/mL, and a mean C_8h that is from 50% to 130%, of the mean C_8h provided by an equal dose of an immediate release liquid solution of sodium oxybate administered at t₀ and t_4h in equally divided doses approximately two hours after a standardized evening meal, and</li><li>b) the formulation releases (i) at least 80% of its gamma-hydroxybutyrate at 3 hours when tested in a dissolution apparatus 2 according to USP 38 <711> in 900 mL of 0.05M monobasic potassium phosphate buffer pH 6.8 at a temperature of 37° C and a paddle speed of 75 rpm, and (ii) from 10% to 65%, of its gamma-hydroxybutyrate at one hour and three hours when tested in a dissolution apparatus 2 according to USP 38 <711> in 900 mL of 0.1N hydrochloric acid at a temperature of 37°C and a paddle speed of 75 rpm, and</li><li>c) the modified release portion releases greater than 80% of its gamma-hydroxybutyrate at 3 hours in a dissolution test started in 750 mL of 0.1N hydrochloric acid for 2 hours then switched to 950 mL 0.05M monobasic potassium phosphate buffer adjusted to pH 6.8 at a temperature of 37°C and a paddle speed of 75 rpm.</li></ol></li><li>7. A modified release formulation of gamma-hydroxybutyrate comprising immediate release and modified release portions, wherein: a) said immediate release portion releases greater than 80% of its gamma- hydroxybutyrate at one hour when tested in a dissolution apparatus 2 according to USP 38 <711> in 900 mL of 0.1N hydrochloric acid at a temperature of 37°C and a paddle speed of 75 rpm; <ul id="ul0007" list-style="none" compact="compact"><li>b) said modified release portion releases less than 20% of its gamma-hydroxybutyrate at one hour when tested in a dissolution apparatus 2 according to USP 38 <711> in 900 mL of 0.1N hydrochloric acid at a temperature of 37°C and a paddle speed of 75 rpm; and</li><li>c) said modified release portion releases greater than 80% of its gamma-hydroxybutyrate at three hours when tested in a dissolution apparatus 2 according to USP 38 <711> in 900 mL of 0.05M monobasic potassium phosphate buffer pH 6.8 at a temperature of 37° C and a paddle speed of 75 rpm.</li></ul></li><li>8. A modified release formulation of gamma-hydroxybutyrate comprising immediate release and modified release portions, wherein: <ol id="ol0019" compact="compact"><li>a) said immediate release portion releases greater than 80% of its gamma-hydroxybutyrate at one hour when tested in a dissolution apparatus 2 according to USP 38 <711> in 900 mL of 0.1N hydrochloric acid at a temperature of 37°C and a paddle speed of 75 rpm;</li><li>b) said modified release portion releases less than 20% of its gamma-hydroxybutyrate at one hour when tested in a dissolution apparatus 2 according to USP 38 <711> in 900 mL of 0.1N hydrochloric acid at a temperature of 37°C and a paddle speed of 75 rpm;</li><li>c) said modified release portion releases greater than 80% of its gamma-hydroxybutyrate at three hours when tested in a dissolution apparatus 2 according to USP 38 <711> in 900 mL of 0.05M monobasic potassium phosphate buffer pH 6.8 at a temperature of 37° C and a paddle speed of 75 rpm; and</li><li>d) said modified release portion releases greater than 80% of its gamma-hydroxybutyrate at 3 hours in a dissolution test started in 750 mL of 0.1N hydrochloric acid for 2 hours then switched to 950 mL 0.05M monobasic potassium phosphate buffer adjusted to pH 6.8 at a temperature of 37°C and a paddle speed of 75 rpm.</li></ol></li><li>9. A modified release formulation of gamma-hydroxybutyrate, wherein a 4.5g, 6g, 7.5g, and 9g dose of the formulation has been shown to achieve a relative bioavailability (RBA) of greater than 80% when compared to an equal dose of an immediate release liquid solution of sodium oxybate administered at t₀ and t_4h in equally divided doses, when administered approximately two hours after a standardized evening meal.</li><li>10. A modified release formulation of gamma-hydroxybutyrate, wherein a 4.5g and a 9g dose of the formulation has been shown to achieve a relative bioavailability (RBA) of greater than 80% when compared to an equal dose of an immediate release liquid solution of sodium oxybate administered at t₀ and t_4h in equally divided doses, when administered approximately two hours after a standardized evening meal.</li><li>11. A modified release formulation of gamma-hydroxybutyrate that yields a plasma concentration versus time curve when administered once nightly at a strength of 4.5g, 6.0 g or 7.5 g approximately two hours after a standardized evening meal substantially as depicted in <figref idref="f0006">Figure 12</figref> or <figref idref="f0007">Figure 13</figref> for the corresponding strength.</li><li>12. A modified release formulation of gamma-hydroxybutyrate that yields a plasma concentration versus time curve substantially as depicted in <figref idref="f0011">Figure 22</figref> when administered once nightly at a strength of 4.5 g approximately two hours after a standardized evening meal.</li><li>13. A modified release formulation of gamma-hydroxybutyrate that yields a dissolution profile substantially as depicted in <figref idref="f0004">Figure 7 and Figure 8</figref>.</li><li>14. A modified release formulation of gamma-hydroxybutyrate that yields a dissolution profile substantially as depicted in <figref idref="f0010">Figure 20</figref> and <figref idref="f0011">Figure 21</figref>.</li><li>15. A modified release formulation of gamma-hydroxybutyrate comprising immediate release and modified release portions wherein said modified release portion yields a dissolution profile substantially as depicted in <figref idref="f0002">Figure 3</figref> or <figref idref="f0008">16</figref>.</li><li>16. A modified release formulation of gamma-hydroxybutyrate, comprising immediate release and modified release portions that yields a dissolution profile between the minimum and maximum values depicted in <figref idref="f0013">Figure 25 and Figure 26</figref>.</li><li>17. A modified release formulation of gamma-hydroxybutyrate, comprising immediate release and modified release portions that yields a dissolution profile between the minimum and maximum values depicted in <figref idref="f0013">Figure 26</figref> and <figref idref="f0014">Figure 28</figref>.</li><li>18. A modified release formulation of gamma-hydroxybutyrate, comprising immediate release and modified release portions that yield a dissolution profile between the minimum and maximum values depicted in <figref idref="f0014">Figure 27 and Figure 28</figref>.</li><li>19. A modified release formulation of gamma-hydroxybutyrate yielding a dissolution profile substantially as shown in any of <figref idref="f0015 f0016 f0017 f0018 f0019 f0020 f0021 f0022 f0023 f0024 f0025 f0026 f0027 f0028 f0029 f0030 f0031 f0032 f0033 f0034 f0035 f0036 f0037 f0038 f0039 f0040 f0041 f0042 f0043 f0044 f0045">Figures 29 through 89</figref>.</li><li>20. A modified release formulation of gamma-hydroxybutyrate that yields a plasma concentration versus time curve when administered once nightly at a strength of 4.5 g, 7.5 g or 9.0 g approximately two hours after a standardized evening meal substantially as depicted in <figref idref="f0046">Figure 90</figref> for the corresponding strength.</li><li>21. The formulation of any of clauses 2, 3, 9 and 10, wherein the formulation releases (a) at least 80% of its gamma-hydroxybutyrate at three hours when tested in a dissolution apparatus 2 according to USP 38 <711> in 900 mL of 0.05M monobasic potassium phosphate buffer pH 6.8 at a temperature of 37° C and a paddle speed of 75 rpm, and (b) from 10% to 65%, of its gamma-hydroxybutyrate at one hour and three hours when tested in a dissolution apparatus 2 according to USP 38 <711> in 900 mL of 0.1N hydrochloric acid at a temperature of 37°C and a paddle speed of 75 rpm.</li><li>22. The formulation of any of clauses 1-10, comprising immediate release and modified release portions, wherein said modified release portion releases greater than 80% of its gamma-hydroxybutyrate at one hour when tested in a dissolution apparatus 2 according to USP 38 <711> in 900 mL of 0.05M monobasic potassium phosphate buffer pH 6.8 at a temperature of 37° C and a paddle speed of 75 rpm.</li><li>23. The formulation of any of clauses 2, 3, 9 and 10, comprising immediate release and modified release portions, wherein: <ol id="ol0020" compact="compact"><li>a) said immediate release portion releases greater than 80% of its gamma-hydroxybutyrate at one hour when tested in a dissolution apparatus 2 according to USP 38 <711> in 900 mL of 0.1N hydrochloric acid at a temperature of 37°C and a paddle speed of 75 rpm;</li><li>b) said modified release portion releases less than 20% of its gamma-hydroxybutyrate at one hour when tested in a dissolution apparatus 2 according to USP 38 <711> in 900 mL of 0.1N hydrochloric acid at a temperature of 37°C and a paddle speed of 75 rpm; and</li><li>c) said modified release portion releases greater than 80% of its gamma-hydroxybutyrate at one hour when tested in a dissolution apparatus 2 according to USP 38 <711> in 900 mL of 0.05M monobasic potassium phosphate buffer pH 6.8 at a temperature of 37° C and a paddle speed of 75 rpm.</li></ol></li><li>24. The formulation of any of clauses 2, 3, 9, and 10 comprising immediate release and modified release portions, wherein: a) the formulation releases at least 80% of its gamma-hydroxybutyrate at 3 hours when tested in a dissolution apparatus 2 according to USP 38 <711> in 900 mL of 0.05M monobasic potassium phosphate buffer pH 6.8 at a temperature of 37° C and a paddle speed of 75 rpm, <ul id="ul0008" list-style="none" compact="compact"><li>b) the formulation releases from 10% to 65%, of its gamma-hydroxybutyrate at one hour when tested in a dissolution apparatus 2 according to USP 38 <711> in 900 mL of 0.1N hydrochloric acid at a temperature of 37°C and a paddle speed of 75 rpm, and</li><li>c) the modified release portion releases greater than 80% of its gamma-hydroxybutyrate at 3 hours in a dissolution test started in 750 mL of 0.1N hydrochloric acid for 2 hours then switched to 950 mL 0.05M monobasic potassium phosphate buffer adjusted to pH 6.8 at a temperature of 37°C and a paddle speed of 75 rpm.</li></ul></li><li>25. The formulation of any of clauses 2, 3, 9 and 10 comprising immediate release and modified release portions, wherein: <ol id="ol0021" compact="compact"><li>a) the formulation releases at least 80% of its gamma-hydroxybutyrate at 3 hours when tested in a dissolution apparatus 2 according to USP 38 <711> in 900 mL of 0.05M monobasic potassium phosphate buffer pH 6.8 at a temperature of 37° C and a paddle speed of 75 rpm,</li><li>b) the formulation releases 10% to 65% of its gamma-hydroxybutyrate at one hour and at three hours when tested in a dissolution apparatus 2 according to USP 38 <711> in 900 mL of 0.1N hydrochloric acid at a temperature of 37°C and a paddle speed of 75 rpm,</li><li>c) the formulation releases greater than 60% of its gamma-hydroxybutyrate at 10 hours when tested in a dissolution apparatus 2 according to USP 38 <711> in 900 mL of 0.1N hydrochloric acid at a temperature of 37°C and a paddle speed of 75 rpm, and</li><li>d) the modified release portion releases greater than 80% of its gamma-hydroxybutyrate at 3 hours in a dissolution test started in 750 mL of 0.1N hydrochloric acid for 2 hours then switched to 950 mL 0.05M monobasic potassium phosphate buffer adjusted to pH 6.8 at a temperature of 37°C and a paddle speed of 75 rpm.</li></ol></li><li>26. The formulation of any of clauses 1-10, wherein the formulation achieves an in vitro dissolution profile: <ol id="ol0022" compact="compact"><li>a) measured in a dissolution apparatus 2 according to USP 38 <711> in 900 mL of 0.1N hydrochloric acid at a temperature of 37°C and a paddle speed of 75 rpm, characterized by the percentage of gamma-hydroxybutyrate dissolved being: <ol id="ol0023" compact="compact"><li>(i) from 40% to 65% at 1 hour,</li><li>(ii) from 40% to 65% at 3 hours,</li><li>(iii) from 47% to 85% at 8 hours,</li><li>(iv) greater or equal to 60% at 10 hours,</li><li>(v) greater or equal to 80% at 16 hours, and</li></ol></li><li>b) measured in a dissolution apparatus 2 according to USP 38 <711> in 900 mL of 0.05M monobasic potassium phosphate buffer pH 6.8 at a temperature of 37° C and a paddle speed of 75 rpm, characterized by the percentage of gamma-hydroxybutyrate dissolved being: <ol id="ol0024" compact="compact"><li>(i) from 43% to 94% at 0.25 hour,</li><li>(ii) greater or equal to 65 % at 0.35 hour, and</li><li>(iii) greater or equal to 88% at 1 hour.</li></ol></li></ol></li><li>27. The formulation of any of clauses 1 and 4-10, wherein a 7.5 g dose of the formulation has been shown to achieve a mean AUC _inf of greater than 340 hr•microgram/mL.</li><li>28. The formulation of any of clauses 1 and 4-10, wherein a 7.5 g dose of the formulation has been shown to achieve a mean AUC _inf of greater than 340 hr•microgram/mL, and a mean C_8h that is from 50% to 130% of the mean C_8h provided by an equal dose of immediate release liquid solution of sodium oxybate administered at t₀ and t_4h in equally divided doses approximately two hours after a standardized evening meal.</li><li>29. The formulation of any of clauses 1-8, wherein a 4.5g, 6g, 7.5g, and 9g dose of the formulation has been shown to achieve a relative bioavailability (RBA) of greater than 80% when compared to an equal dose of an immediate release liquid solution of sodium oxybate administered at t₀ and t_4h in equally divided doses, when administered approximately two hours after a standardized evening meal.</li><li>30. The formulation of any of clauses 1-8, wherein a 4.5g and a 9g dose of the formulation has been shown to achieve a relative bioavailability (RBA) of greater than 80% when compared to an equal dose of an immediate release liquid solution of sodium oxybate administered at t₀ and t_4h in equally divided doses, when administered approximately two hours after a standardized evening meal.</li><li>31. The formulation of any of clauses 1-10 comprising an immediate release gamma-hydroxybutyrate portion and a modified release gamma-hydroxybutyrate portion.</li><li>32. The formulation of any of clauses 1-10 comprising an immediate release gamma-hydroxybutyrate portion and a modified release gamma-hydroxybutyrate portion, wherein the molar percentage of the gamma-hydroxybutyrate in the immediate release portion relative to the total of gamma-hydroxybutyrate in the formulation ranges from 10% to 65%.</li><li>33. The formulation of any of clauses 1-10 comprising an immediate release gamma-hydroxybutyrate portion and a modified release gamma-hydroxybutyrate portion, wherein the molar percentage of the gamma-hydroxybutyrate in the immediate release portion relative to the total of gamma-hydroxybutyrate in the formulation ranges from 40% to 60%.</li><li>34. The formulation of any of clauses 1-10 comprising immediate release and modified release portions wherein said modified release portion comprises a time-dependent release mechanism and a pH-dependent release mechanism.</li><li>35. The formulation of any of clauses 1-10 comprising immediate release and modified release portions, wherein: <ol id="ol0025" compact="compact"><li>a) the modified release portion comprises coated particles of gamma-hydroxybutyrate;</li><li>b) the coating of said modified release particles of gamma-hydroxybutyrate comprises a polymer carrying free carboxylic groups and a hydrophobic compound having a melting point equal or greater than 40°C; and</li><li>c) the ratio of gamma-hydroxybutyrate in the immediate release portion and the modified release portion is from 10/90 to 65/35.</li></ol></li><li>36. The formulation of any of clauses 1-10 comprising immediate release and modified release portions, wherein: <ol id="ol0026" compact="compact"><li>a) the modified release portion comprises coated particles of gamma-hydroxybutyrate;</li><li>b) the coating of said modified release particles of gamma-hydroxybutyrate comprises a polymer carrying free carboxylic groups and a hydrophobic compound having a melting point equal or greater than 40°C;</li><li>c) the weight ratio of the hydrophobic compound to the polymer carrying free carboxylic groups is from 0.4 to 4;</li><li>d) the ratio of gamma-hydroxybutyrate in the immediate release portion and the modified release portion is from 10/90 to 65/35; and</li><li>e) the coating of said modified release particles of gamma-hydroxybutyrate is from 10 to 50% of the weight of the particles.</li></ol></li><li>37. The formulation of any of clauses 1-10 comprising immediate release and modified release portions, wherein: <ol id="ol0027" compact="compact"><li>a) the modified release portion comprises coated particles of gamma-hydroxybutyrate;</li><li>b) the coating of said modified release particles of gamma-hydroxybutyrate comprises a polymer carrying free carboxylic groups having a pH trigger of from 5.5 to 6.97 and a hydrophobic compound having a melting point equal or greater than 40°C;</li><li>c) the weight ratio of the hydrophobic compound to the polymer carrying free carboxylic groups is from 0.4 to 4;</li><li>d) the ratio of gamma-hydroxybutyrate in the immediate release portion and the modified release portion is from 10/90 to 65/35; and</li><li>e) the coating of said modified release particles of gamma-hydroxybutyrate is from 10 to 50% of the weight of the particles.</li></ol></li><li>38. The formulation of any of clauses 35-37 wherein the free carboxylic groups are substantially ionized at pH 7.5.</li><li>39. The formulation of any of clauses 35-37 wherein the polymer carrying free carboxylic groups is selected from the group consisting of: (meth)acrylic acid/alkyl (meth)acrylate copolymers or methacrylic acid and methyl methacrylate copolymers or methacrylic acid and ethyl acrylate copolymers or methacrylic acid copolymers type A, B or C, cellulose derivatives carrying free carboxylic groups, cellulose acetate phthalate, cellulose acetate succinate, hydroxypropyl methyl cellulose phthalate carboxymethylethyl cellulose, cellulose acetate trimellitate, , hydroxypropyl methyl cellulose acetate succinate, polyvinyl acetate phthalate, zein, shellac, alginate, and mixtures thereof.</li><li>40. The formulation of any of clauses 35-37 wherein the polymer carrying free carboxylic groups is selected from the group consisting of copolymers of methacrylic acid and ethyl acrylate 1:1, copolymers of methacrylic acid and methylmethacrylate 1:2, and mixtures thereof.</li><li>41. The formulation of any of clauses 35-37 wherein the hydrophobic compound is selected from the group consisting of hydrogenated vegetable oils, vegetable waxes, wax yellow, wax white, wax microcrystalline, lanolin, anhydrous milk fat, hard fat suppository base, lauroyl macrogol glycerides, polyglyceryl diisostearate, diesters or triesters of glycerol with a fatty acid, and mixtures thereof.</li><li>42. The formulation of any of clauses 35-37 wherein the hydrophobic compound is selected from the group consisting of hydrogenated cottonseed oil, hydrogenated soybean oil, hydrogenated palm oil, glyceryl behenate, hydrogenated castor oil, candelilla wax, tristearin, tripalmitin, trimyristin, yellow wax, hard fat or fat that is useful as suppository bases, anhydrous dairy fats, lanolin, glyceryl palmitostearate, glyceryl stearate, lauryl macrogol glycerides, polyglyceryl diisostearate, diethylene glycol monostearate, ethylene glycol monostearate, omega 3 fatty acids, and mixtures thereof.</li><li>43. The formulation of any of clauses 35-37 wherein the hydrophobic compound is selected from the group consisting of hydrogenated cottonseed oil, hydrogenated soybean oil, hydrogenated palm oil, glyceryl behenate, hydrogenated castor oil, candelilla wax, tristearin, tripalmitin, trimyristin, beeswax, hydrogenated poly-1 decene, carnauba wax, and mixtures thereof.</li><li>44. The formulation of any of clauses 35-37 wherein: <ol id="ol0028" compact="compact"><li>a) the polymer carrying free carboxylic groups comprises from 100% poly (methacrylic acid, ethyl acrylate) 1:1 and 0% poly (methacrylic acid, methylmethacrylate) 1:2 to 2% poly (methacrylic acid, ethyl acrylate) 1:1 and 98% poly (methacrylic acid, methylmethacrylate) 1:2; and</li><li>b) the hydrophobic compound comprises hydrogenated vegetable oil.</li></ol></li><li>45. The formulation of any of clauses 1 and 5-8 wherein the modified release portion comprises particles comprising: <ol id="ol0029" compact="compact"><li>a) an inert core;</li><li>b) a coating; and</li><li>c) a layer comprising the gamma hydroxybutyrate interposed between the core and the coating.</li></ol></li><li>46. The formulation of any of clauses 1 and 5-8 wherein the modified release portion comprises particles having a volume mean diameter of from 200 to 800 microns.</li><li>47. The formulation any of clauses 35-37 in the form of a powder that is intended to be dispersed in water prior to administration, further comprising an acidifying agent and a suspending or viscosifying agent.</li><li>48. The formulation of any of clauses 35-37 and 47 in the form of a powder that is intended to be dispersed in water prior to administration, further comprising from 1.2 to 15% of an acidifying agent.</li><li>49. The formulation of any of clauses 35-37 and 47 in the form of a powder that is intended to be dispersed in water prior to administration, further comprising from 1 to 15% of a viscosifying or suspending agent.</li><li>50. The formulation of any of clauses 35-37 and 47 in the form of a powder that is intended to be dispersed in water prior to administration, further comprising from 1 to 15% of a suspending or viscosifying agent selected from a mixture of xanthan gum, carrageenan gum and hydroxyethylcellulose or xanthan gum and carrageenan gum.</li><li>51. The formulation of any of clauses 35-37 and 47 in the form of a powder that is intended to be dispersed in water prior to administration, further comprising: <ol id="ol0030" compact="compact"><li>a) a suspending or viscosifying agent selected from xanthan gum, medium viscosity sodium carboxymethyl cellulose, mixtures of microcrystalline cellulose and sodium carboxymethyl cellulose, mixtures of microcrystalline cellulose and guar gum, medium viscosity hydroxyethyl cellulose, agar, sodium alginate, mixtures of sodium alginate and calcium alginate, gellan gum, carrageenan gum grade iota, kappa or lambda, medium viscosity hydroxypropylmethyl cellulose, and mixtures thereof; and</li><li>b) an acidifying agent selected from malic acid, citric acid, tartaric acid, adipic acid, boric acid, maleic acid, phosphoric acid, ascorbic acid, oleic acid, capric acid, caprylic acid, benzoic acid, and mixtures thereof.</li></ol></li><li>52. The formulation of any of clauses 35-37 and 47 in the form of a powder that is intended to be dispersed in water prior to administration, further comprising: <ol id="ol0031" compact="compact"><li>a) from 1.2 to 15% of an acidifying agent selected from malic acid and tartaric acid; and</li><li>b) from 1 to 15% of a suspending or viscosifying agent selected from a mixture of xanthan gum, carrageenan gum and hydroxyethylcellulose or xanthan gum and carrageenan gum.</li></ol></li><li>53. The formulation of any of clauses 1 -10 wherein: <ol id="ol0032" compact="compact"><li>a) a 4.5 g dose has been shown to yield a mean C_8h from 4.7 to 9.0, from 5.4 to 8.3, from 6.1 to 7.6, from 3.5 to 7.0, or from 4.0 to 5.5 microgram/mL;</li><li>b) a 6 g dose has been shown to achieve a mean C_8h from 6.3 to 16.7, from 7.3 to 15.4, from 8.2 to 14.1, from 8.9 to 16.7, from 10.2 to 15.4, or from 1 1.5 to 14.1 microgram/mL;</li><li>c) a 7.5 g dose has been shown to achieve a mean C_8h from 13.0 to 40.3, 16.0 to 26.0, from 15.0 to 25.0, from 17.5 to 22.0, from 21.6 to 40.3, from 24.7 to 37.2, or from 27.8 to 34.1 microgram/mL; when administered once approximately two hours after a standardized evening meal; or</li><li>d) any combination thereof.</li></ol></li><li>54. The formulation of any of clauses 1 and 4-10 wherein a 7.5 g dose of the formulation has been shown to achieve a mean AUC_inf of greater than 300 hr•microgram/mL and a mean C_max of greater than 70 microgram/mL when administered once approximately two hours after a standardized evening meal.</li><li>55. The formulation of any of clauses 1 -10 wherein a 7.5 g dose of the formulation has been shown to achieve a mean AUC_inf of greater than 350 hr•microgram/mL and a mean C_max of greater than 80 microgram/mL when administered once approximately two hours after a standardized evening meal.</li><li>56. The formulation of any of clauses 1 -10 wherein a 4.5 g, 6.0 g, 7.5 g or 9.0 g dose of the formulation or any combination thereof has been shown to achieve a ratio of mean AUC_8h to mean AUC_inf of greater than 0.80, 0.85, 0.90, 0.95 or 0.98 when administered once approximately two hours after a standardized evening meal.</li><li>57. The formulation of any of clauses 1-10 wherein a 4.5 g, 6.0 g, 7.5 g or 9.0 g dose of the formulation has been shown to achieve a median T_max within one hundred fifty, one hundred twenty, ninety, sixty or thirty minutes of the median T_max of half the dose of an immediate release liquid solution of sodium oxybate, when administered approximately two hours after a standardized evening meal.</li><li>58. The formulation of any of clauses 1-10 wherein a 4.5 g, 6.0 g, 7.5 g or 9.0 g dose of the formulation has been shown to achieve a mean C_6h or mean C_7h greater than, and a mean C_10h less than, the mean C_4h of half the dose of an immediate release liquid solution of sodium oxybate, when administered approximately two hours after a standardized evening meal.</li><li>59. The formulation of any of clauses 1 -10 wherein a 4.5, 6.0, 7.5 and 9.0 g dose of the formulation has been shown to achieve a mean AUC_inf of greater than 80% of the mean AUC_inf provided by an equal dose of immediate release liquid solution of sodium oxybate administered at t₀ and t_4h in equally divided doses approximately two hours after a standardized evening meal, and a mean C_8h less than 95%, 90 or 85% of the mean C_8h provided by an equal dose of immediate release liquid solution of sodium oxybate administered at t₀ and t_4h in equally divided doses approximately two hours after a standardized evening meal.</li><li>60. The formulation of any of clauses 1 and 5-8, wherein the modified release portion and the immediate release portion comprise structurally discreet modified release particles and immediate release particles.</li><li>61. The formulation of any of clauses 1 and 5-8, wherein the modified release portion and the immediate release portion comprise structurally indiscreet particles.</li><li>62. The formulation of any of clauses 3, 9, and 10, wherein the comparison to an equal dose of immediate release liquid solution of sodium oxybate administered at t₀ and t_4h in equally divided doses is performed in a cross-over trial.</li><li>63. The formulation of any of clauses 2, 3, 9, and 10, wherein the recited pharmacokinetic parameter or parameters has been shown either directly or indirectly.</li><li>64. The formulation of clauses 1-63 in a dosage form selected from the group consisting of tablets, powders and capsules.</li><li>65. The formulation of clauses 1-64, wherein the gamma-hydroxybutyrate is in the form of sodium oxybate.</li><li>66. The formulation of any of clauses 1-65 in the form of a powder.</li><li>67. The formulation of any clauses 1-66 effective to treat narcolepsy Type 1 or Type 2, wherein said treatment of narcolepsy is defined as reducing excessive daytime sleepiness or reducing the frequency of cataplectic attacks.</li><li>68. The formulation of clauses 1-67 effective to induce sleep for eight consecutive hours.</li><li>69. The modified release formulation of gamma-hydroxybutyrate of any of the foregoing clauses for use in the treatment of a disorder treatable with sodium oxybate in a human subject in need thereof, said formulation being orally administered in a single bedtime daily dose to said human equivalent to 3.0 to 12.0 g of sodium oxybate.</li><li>70. The modified release formulation of gamma-hydroxybutyrate of any of the clauses 1-68 for use in the treatment of cataplexy in narcolepsy or excessive daytime sleepiness ("EDS") in narcolepsy, said formulation being orally administered a single bedtime daily dose to said human subject equivalent to 3.0 to 12.0 g of sodium oxybate.</li><li>71. The modified release formulation of gamma-hydroxybutyrate for use according to clause 69 or 70 wherein, compared to a dosing regimen consisting of administering half the dose at t₀ and another half of the dose at t_4h in an immediate release liquid solution, the administration of said formulation has been shown to produce less confusion, less depressive syndrome, less incontinence, less nausea or less sleepwalking.</li><li>72. The modified release formulation of gamma-hydroxybutyrate for use according to clause 70 wherein, compared to a dosing regimen consisting of administering half the dose at t₀ and another half of the dose at t_4h in an immediate release liquid solution, the administration of said formulation has been shown to <ol id="ol0033" compact="compact"><li>a) decrease the number of cataplectic attacks;</li><li>b) decrease daytime sleepiness when measured on the Epworth Sleepiness Scale;</li><li>c) decrease daytime sleepiness as measured by the Maintenance of Wakefulness Test based on EEG measures of wakefulness;</li><li>d) improve said subject's Clinical Global Impression (CGI) rating of sleepiness;</li><li>e) decrease disturbed nocturnal events or adverse respiratory events as determined by polysomnogram (PSG);</li><li>f) decrease hypnagogic hallucinations;</li><li>g) decrease sleep paralysis;</li><li>h) increase MWT sleep latency;</li><li>i) decrease PSG transitions from N2 to N3 and REM sleep to wake and N1 sleep;</li><li>j) decrease number of arousals in NT1 and/or NT2 subjects obtained from a PSG;</li><li>k) improve sleep quality and refreshing nature of sleep in NT1 and/or NT2 subjects as measured on Visual Analog Scale (VAS);</li><li>l) decrease the number of wakenings; or</li><li>m) any combination thereof.</li></ol></li></ol>