Method for making uniformly sized particles from water-insoluble organic compounds

METHOD FOR MAKING UNIFORMLY SIZED PARTICLES FROM WATER-INSOLUBLE ORGANIC COMPOUNDS BACKGROUND OF THE INVENTION

Particles of compounds having low water-solubility are commonly used in a wide variety of applications, including ceramics, paints, inks, dyes, lubricants, pesticides, insecticides, fungicides, fertilizers, chromatography columns, cosmetics, lotions, ointments, and detergents. Aqueous dispersions of particles are used in many cases to avoid hazards such as flammability and toxicity associated with organic solvents. Such dispersions typically have a broad range of particle size.

In many cases product performance is improved by controlling the particle size distribution. In general, smaller particles of a compound will dissolve faster than larger particles of the same compounds. Control of particle size is, therefore, important in controlling the rate of solubilization.

Many drugs have been formulated as particles for controlled-release following oral administration or implantation. Particle size is one important factor affecting the release.rate of these drugs. Those skilled in the art can discern other examples for using particle size to control product performance for the substances listed above.

Drugs that are insoluble in water can have significant benefits when formulated as a stable suspension of particles of less than three microns diameter. In this particulate form, the drug can be injected intravenously, circulate in blood, and be preferentially accumulated in, for example, the reticuloendothelial system, where it can facilitate normal reticuloendothelial functions such as detoxification. Alternatively, the drug can reside in the rstlouloendothellal ־״־־ where ״ _{ls stored unt01־ ״ublll־־} or metabolized into an active form which circulates in blood to other tissues for efficacy. _Ihl״_״310, _־_{r־1־a3־ ־f ־׳י״״} י : drug can provide more constant drug concentrations In plasma ’ lj ״״ a period ־f hours, days, weeks, or months, resulting 1״ :1 improved therapeutic efficacy. Biodegradable particles which ־re radiopaque or labelled with a radioisotope are useful for ? diagnostic imaging of organs, such as liver and spleen, ״_ith . high concentrations of fixed reticuloendothelial function.

^{10 Hany ad}״^a^taS^־’ have already been recognized for ״ ’ insoluble particulate radiopaque contrast media, for example, as explained in Improvement _tn Radiographic Contrast Media ; Through the Development of Colloidal or Particulate Media: an 1Ί Analysis, by Harry W. Fischer, Journal of Theoretical ־י _; Biolm. «7: 653-670 (1_W). _Mor־ recent papers on this : subject include Violante, M. R., Fischer, H. W., and Mahoney, ’7 J.A., Particulate Contrast Media, Invest. Radiol,. J5: _S329

November-December I960; and Violante, M. JU, Dean, P. B., . Fischer, H. W., and Mahoney, J. A., Particulate Contrast

Media for Computer Tomographic Scanning of the Liver, Invest -1 Radiol_1_5: 171 November-December 1980.

²י^{There are} enormous medical implications for the !3 intravenous administration of drugs formulated as suspensions ^!4 of particles of three microns diameter, or less, which can be !5 accumulated by phagocytic cells and slowly solubilized for :6 sustained release into plasma for circulation to other organs i׳ and tissues. Obvious drug classes appropriate for formulation .; as particulate suspensions include: antineoplastics, antimicrobials, antivirals, anticoagulants, antihypertensives, 0 antihistamines, antimalarials, male and . female contraceptives,

׳,ז-

ו antiepileptics, depressants and adrenocortical steroid cardiac glycosides, insoluble vitamins, hyperglycemic agents, drugs, and others, ^,״ alcohol abuse, drug abuse antidepressants,

3, hormones and hormone antagonists, Immunosuppressants, beta-blockers, water³ympathomlmetics, hypcglyoemlc agents, , analgesics, tranqulliaer־, mood altering The treatment of deficiency diseases,

1, and many others could be Improved ״!th intravenous administration of particulate suspension־ of the appropriate drug, other medical applications for Particulate drug ־״־pensions _{wl״ appapent} in the art.

Accurate control of particle 3₁₂־ essential _f0_ sate and efficacious use of these formulation־. Particles «״Ct be less than three microns In diameter to safely pass through capillaries without causing emboli. This _{ls cri״oal}for intravenous administration sl_n0־ the particles must pa־־ through lung capillaries before reaching the fixed rcticuloendcthellal ״.־. _of _{livep and} ־_plee״.

. particle diameters of 0.01-0.1 micron could result In selective accumulation of these particles In certain tissues, ־g., neoplastlc tissue, ״here capillaries are somewhat more porous than capillaries of normal tissues. _S״_sp_־n־_{tons of}particles with diameters greater than 10 microns could be useful for selective Intra-arterial administration to purposely embolize vessels feeding abnormal tissue neoplasm. Accurate and precise control of particle J is essential for efficacy while minimizing ' effects in each of these applications.

Conventional methods of making water-insoluble compounds produce particles of many different sizes, many of such as a diameters or avoiding adverse /2 which are unsuitable for the purpose at hand. Mechanically sorting or separating a desired particle size from a mix of sizes is difficult and unsatisfactory. Centrifuging and filtration do not produce high yields of particles that are all precisely the same desired size.

Investigations of water-insoluble radiopaque contrast materials required uniform particles in specific sizes that were very difficult to obtain by conventional methods. Precipitation as a way of directly forming particles of a predetermined size was then investigated. Partial success was achieved with one material and one method as reported in Particulate Contrast Media, Investigative Radiology, 15; S329 November-December 1980; but this method would not work with other materials and would not allow accurate variation and control of the particle size produced.

Further investigation led to the invention of this application, which is effective with any drug or other compound having a solubility in water of preferably less than one part per ten thousand to obtain a predetermined particle size of the water-insoluble drugs or other compounds used in aqueous dispersions.

SUMMARY OF THE INVENTION

The invention involves a method of making uniformly sized particles of a solid, water-insoluble organic compound, comprising:

(a) preparing a solution of solid organic compound in a watermiscible organic solvent for the compound, the solid organic compound having essentially little aqueous solubility;

75250/2 (b) infusing an aqueous precipitating liquid into the organic solution at a temperature between about -10°C and about 100°C and at an infusion rate of from about 0.01 ml per min. to about 1000 ml per min. per 50 ml unit volume of solution, so as to produce a suspension of precipitated amorphous, non-crystalline solid organic compound in the form of substantially non-aggregated particles of a uniform size selected from a particle diameter range of up to about 10 microns, the particle size being directly related to the solution temperature during precipitation and inversely related to the infusion rate;

(c) separating the particles from the organic liquids and washing in aqueous washing liquid.

Agitation of the solution being infused with precipitating liquid is preferred. This can be accomplished by stirring, shaking, combining two streams of liquid, by the infusing itself and by other techniques known to those skilled in the art.

In preferred embodiments of the invention, additional aqueous precipitating liquid is added to the suspension before the particles are separated from the organic solvents. Separation can be accomplished, for example, by centrifugation, membrane filtration, reverse osmosis, or other methods.

The aqueous washing liquid can be the same as the aqueous precipitating liquid, and it can be pharmaceutically acceptable for injecting into a patient.

75250/2

The aqueous precipitating liquid can be water, a solution of a mineral salt, or a surfactant solution. Suitable aqueous surfactant solutions include 5% polyvinyl pyrrolidone C-30, 0.1% polyvinyl pyrrolidone C-15, 0.1% human serum albumin, 0.1% Pluronic F-68 (poloxamer 188), and 0.33% gelatin, alone or combined with 0.6% hetastarch, 0.02% propylene glycol, or 2% sucrose. The aqueous precipitating liquid can be infused through a needle of standard gauge.

a 1

1.5

18.

21.

The mean particle diameter or the particle־ can be J up to about 10 micro־״, preferably in a range 0Γ 0.01 micron־ to about 5 microns.

|i Particles made according to this invention will !! typically have a particle size distribution with a maximum relative standard deviation of 50%, for example 95% of the particle having a mean size of 1.0 micron will be within the size range of 0.5 to 1.5 microns.

. . The solid organic compound has, preferably, an aqueous solubility of less than about one part per ten • thousand, and the compound may be organo-metallic. Generally, any compound that meets the other requirements of the : invention is suitable, including many drugs. Where heparin , complexes are used, no surfactant is necessary.

The organic solvent can be dimethyl sulfoxide, dimethyl formamide, N,N’-dimethyl acetamide, phenol, isopropanol, or other solvents.

.,Ina preferred embodiment, the method includes the additional step of diluting the organic solution with a nonsolvent liquid such that the ratio of non-solvent to solvent is between about 100:1 and about 1:100, after preparing the organic solution and before the infusion step, so that the particle size is directly related to the ratio of non-solvent to solvent.

In further preferred embodiments, the non-solvent is one in which the organic compound is slightly more soluble :, than in water. The non-solvent can be a lower aliphatic J alcohol.

In particular preferred embodiments, iodipamide ethyl ester, an ethyl ester of a triiodobenzoic acid urn T’ ¹.^{3 dl־S01Ved ln dl}״^{ethil SUlf0Xld־ and}anol; if the ratio of ethanol to dimethyl sulfoxide is ־־ter than about t»0, the men״ particle than about one micron. and if _{the of} _ sulfoxide 1₃₃־1 ־_{than about} • . , t׳⁰״ ^{the mean} Particle diameter s less than about one micron.

BMBF DESCaiPTIOM OF the DBAWTMr.e

Figure 1 is a phases of the compounds

Figure 2 is a graph of free energy of the various used in the invention.

״ . graph of the relationship bet»״־־ _sl2־ , distribution of particles and completion of precipitation.

Figure 3 is a graph . aqueous precipitating liquid) stir _{rate (rpm}j _{and tota1 vQlume} solution at a constant temperature;

time interval between onset and of as .

infusion rate (ml/min.) (of a function of the product of (liters) of the organic ׳ ^{the re}lationship: aqueous ₍ fusion rate (ml/min.) ₄,._{0 + 3־־ ts״r}_״״_{< (rpnJ χ} . organic, solution (1)) defines the parameters for production of , iodipamide ethyl ester particles of ״_na p ticxes of one micron diameter at a temperature (,.״ and in dimethyl sulfoxlde/ethanol; Figure 4 is a graph showing iodipamid size as a function of temperature at a infusion rate of aqueous precipitating liquid constant e ethyl ester constant particle ratio of

[stir rate (rpm) x volume of

Figure 5 is a graph demonstrate _ particle size of varying the infusi־־ precipitating liquid at constant temperature of an iodipamide ethyl ester solution; and to effect on organic solution];

-----ing the

------ion rate of aqueous and stirring rate

Figure 6 is a schematic diagram of preferred steps in the inventive method.

DETAILED DESCRIPTION OF THE INVENTION

This invention concerns the preparation of water!״soluble compounds as uniform particles of ־ predetermined size. The particles are formed by a carefully controlled Precipitation of the compound Into an aqueous phase from an organic solvent in which the compound is soluble.

The physical ohemlcal principles thought to be Involved in this Invention are demonstrated in figures 1 and 2. Figure 1 shows that the free energy of the system is higher when the compound Is dissolved in the organic solvent than when the compound exists in the particulate or crystalline state. During precipitation the compound will naturally convert to the crystalline form-the lowest free energy state-unless It is trapped In the metastable particulate form, a condition where Its free energy Is Intermediate between the solution and the crystalline phases. When properly practiced, this invention enables the trapping of a compound In the metastable particle state, precluding transformation to the crystalline state.

The size distribution of particles formed during precipitation can be correlated with the time interval between onset and completion of precipitation. As shown in Figure 2, a very short time interval results in the production of uniformly sized particles (A), while a very long time interval results in a broad particle size distribution (B). Intermediate conditions produce intermediate particle size distributions.

An important parameter for utilization of this invention is the aqueous solubility of the compound. The invention requires the use of solid organic compounds having essentially little aqueous solubility. H. have round that , compounds which have a water-solubility of less than one part

In ten thousand are Ideally suited for this technology.

. Compounds which are more water-soluble can be used with this I invention; however, th־ higher the solubility the greater the j probability that some 0Γ the compound will dissolve m the ץ aqueous phase and transform to the more stable crystalline : state. Also ^dissolution in the aqueous phase can 1־_ad to a :, broadening of the particle size distribution. For these reasons, we prefer compounds having a water-solubility of less than one part in ten thousand.

In order to make particles of a uniform and • predetermined size having a solubility of less than one part per ten thousand, a solution of the solid organic compound in a suitable organic solvent is prepared. The solution may be ; diluted with a non-solvent that does not cause the drug or _: other compound to precipitate. An aqueous precipitating liquid is also prepared, preferably with a surfactant, in' sufficient quantity to both precipitate the drug or other compound and stabilize the resulting suspension of particles of the compound against aggregation. Water may be used alone as the precipitating liquid when compounds which do not aggregate are used. The aqueous solution is infused into the organic solution under carefully controlled conditions, including: the rate of stirring of the organic solution, the ! rate of infusion of the aqueous solution, the volume of the organic solution and the temperature of the solutions and the : suspension.

In investigations of varying parameters to adjust for particle size, three usable relationships were discovered:

¹ :. (1) diluting the solution with moreof the non-solvent ־ ; produces larger particles, and diluting with less of the non3 ' solvent produces smaller particles; (₂) _hl־her temperatures of ’ the solution during precipitation produce larger particles, , and lower temperatures of the solution during precipitation ; produce smaller particles; and (₃) at a given stirring rate of : the organic solution, faster infusion rates of aqueous / solution produce smaller particles while slower infusion rates produce larger ,particles.

° i “^hen the precipitation is complete, the uniformly י , sized particles are separated from the liquid and washed to remove the organic solvent. In most oases, the particles should be separated from the liquid quickly to prevent ¹4 transformation to a crystalline form.

⁵ Compounds that are used in the invention are solid organic materials, including organometallic compounds, that Γ . have a solubility in water of preferably less than one part per. ten thousand. Otherwise the specific compound and its J purpose are less important to the way the invention works. ^{} The first ste}P ⁱ³ to prepare a solution of the י compound of interest in an organic solvent suitable for that ! compound. This can occur as the compound is synthesized as a

I dissolved solid, or it can be done by simply dissolving the ׳ compound in the solvent of choice.

The solvent is chosen to suit the compound. For ' ' example, dimethylforraamide (DMF) is a solvent for iothalamate ethyl ester (IEE) and i'osefamate ethyl ester (IFE), and dimethylsulfoxide (DMSO) is a solvent for iodipamide ethyl ester (IDE) and IEE. Any satisfactory solvent for the compound that is miscible with water can be used.

The next step .13 to dilute the solution ״!th a non solvent that does not cause the compound to precipitate. The ׳ non-solvent causes greater dispersion of the dissolved i molecules of the compound In the liquid phase. Greater ji dilution of the solution with non-solvsnt produces larger li particles, and less dilution of the solution 1״th non-solvent produces smaller particles.

! The non-solvent should not precipitate the compound ; ״hen it Is added to the solution. Non-solvsnts 1״ ״hloh the . compound 1־ slightly more soluble than In ״_{ater ars} preferred. 1 tower aliphatic alcohols, such as ethanol, are effective non; solvents for solutions of IDE and IEE in DMSO. For the ethyl • esters of trllodobenzoic acid, proportions of non-solvent to : solvent at a ratio, of 2 or more can produce 1 to 3 micron . sized particles (depending on other parameters); and ratios of less than 2 can produce sub-micron particles, at least as i applied to DMSO solutions diluted with ethanol.

To precipitate.the compound from the solution in a . desired particle size, an aqueous solution of a surfactant is : prepared in sufficient quantity to effect complete precipitation of the compound and to stabilize the resulting suspension of particles of the compound against aggregation.

: The surfactant provides the stabilization against aggregation, : and the water is the precipitating agent. Presence of extra surfactant is advisable to ensure stabilization so that precipitated particles suspended in liquid do not aggregate, ί forming particles of an improperly large size. While • surfactants are used in most oases, some compounds appear to form stable, substantially non-aggregated particles without the use of surfactants. Examples of such non-aggregrating compounds are certain .

re certain Heparin complexes.

It is thought that particles surface charge are l_ess 1_{ikely t0}aqueous precipitating particle is sometimes measurement of charge

15 ^ר

1.7

2.0 with relatively high require surfactant in the The surface charge of a as its zeta potential, a off with distance. There above which no surfactant is solution.

referred to which falls .: may be a threshold zeta potential : —. below which, surfactant _{ts ne־dM t־־ k־ep}: P^re01p1tating particles _{fr־m aggregatlng}. _2־up ־ ־ir.otly correlated with the p_01ar״_{y or} ״,, . organic compound. _Thu־. _{ue n־־d fop ־urf״t>nt}: ־d־־״ua Precipitating solution _{be ρΓ}^_״־ ־*. or the charge or polarity of the organic ״־־pound goyea lh the method of the invention. For _exanpl־.

t ־re highly charged, _{and f0!}__״particles when precipitated with water.

. Generally, such a theory notwithstanding, empirical ode will suffice; that is, a precipitation may first be . performed with water, and if aggregation occurs, th״־ a Precipitation in th. pres־־״־ of surfactant is indicated. Surfactants are chosen for their compatibility with the compound and their shim.״ ♦. _t .

their ability to stabilize a suspension of ' particles. For work with IEE and IDE drugs, a ־f 5? polyvinyl pyrrolidone (C-30), 0.1% polyvinyl pyrrolidone (C-15), or 0.1% human serum albumin is preferred. Al0.1% ־־ Pluronlo F-68, [Pdoxamer 188, a p־ly(oxy־th_yl.־״־ ־-־־xypropylene) polymer], a O._33% gelati₀.₃₃ ,״_{J galati״}0.M Hetastarch, 0._{33< 8elatln plu־0}._{00 ־$}and 0.₃₃% gelatin plus z% sucrose, or other surracants known to one skilled in the art can be _used.

compound solution

ו

19,

. 20

To precipitate compound particles in the desired ־־־, the aqueous solution and the organic solution are

Of temperature, ratio of e, and the proportion of non. ----J solution.

of the compound occurs organic solution and the resulting of the solution and resulting achieve the particle size of

Higher solution temperat combined under controlled conditions infusion rate to stirring rat solvent to solvent in the dispersed The precipitation exothermically, heating the suspension. The temperature suspension is controlled to precipitate that is desired.

׳'״ ־־־־״.‘“vxv״ temperatures ^ring precipltaiion produce larger particle־, s״_{d 10״er}solution temperatures during precipitation produce smaller particles.

Also, faster infusion rates at rate of organic solution produce smaller . infusion rates produce larger particles.

Figures three to five show the . . size of varying parameters during precipitation . CMSO solution diluted »1th 1 part solution to 2 parts ethanol constant stirring particles, and slower effects on particle

-----1 of IDE from a ־״ an aqueous solution of _M polyviny! _pyrrolidon־different infusion rates and temperatures.

FIG. 3 shows that as the volume and stirring rate the organic compound lodlpamide ethyl ־־ter and dimethyl ־Ulfoxide/etbanol solution are increased,, the i_nf־״_i0״ _rate proportionally infusion rate (rnl/min.) = 2₃ . ₀._{14 [ν01Μ־}rate (r.p.m.)] to produce particles of 1 micron diameter at 4*C.

aqueous surfactant solution must be increased as defined by: (liters) x stir of of

FIG. 4 shows that at a constant ratio of infusion rate to [stir rate x volume], increased precipitation ־13temperature produces larger particles.

; FIG. 5 plots 3 points from the 20’C temperature line of FIG. 3 for rate of infusion of the precipitation liquid | into the organic solution to approximate the curve by which ן larger particles are formed from slower injection rates, | showing that at a constant ratio of temperature to [stir rate ל x volume], particle size is inversely related to the rate of h infusion of the precipitating liquid.

When FIGS. 3-5 are considered together, they show _r clearly that higher temperatures and slower mixing rates i; produce larger particles, and lower temperatures and faster i; mixing rates produce smaller particles. Another parameter ! that can be varied to affect particle size is the amount of _; dilution of the solution before precipitation occurs.

? . . When the precipitation is complete, extra aqueous surfactant solution can be added to further stabilize the suspended particles against agglomeration. The extra solution can be added at a rapid rate, since essentially all the compound is now precipitated in uniformly sized particles.

. The precipitated particles are promptly separated from the organic solvents to prevent redissolving and reprecipitation of particles at undesirable sizes. Centrifuging is a preferred way to perform the separation. Other methods, including membrane filtration, reverse osmosis, and others known to persons skilled in the art may also be used to remove i: undesired substances. Promptly after separating the particles .: from the organic liquid, the particles are washed or rinsed with normal saline solution to remove solvent and excess surfactant.

The method of the invention is illustrated by the '' r־H״־i״_e ־ζ״־ρ1־־ which, _h0״ever, _{not Hm1t}. as described above and set forth in the claims.

Examples 1 to 19 are presented in Table I. The . ־Olid organic compound was dissolved In the organic solvent J ״־d then diluted (except where Indicated) by the ״on-solvent, ;i The aqueous precipitating liquid was then infused through a _; needle at the given rate into the solution, at the given . temperature and while stirring at the given stirring rate.

The size of the particles obtained Is shown for each example.

Table la

<td></td><td>^Exa״P^le Example------------- --------------------------—__2__________.</td>

<td> i! 1. 1;</td><td> ~^anl־</td>

<td> H ___ !1</td><td> __________________________ (1/4 sec)</td>

<td> ii ²־ : *</td><td> K °.² “¹,SSS °.² ר»״“,*״* _______ suiioxlae sulfoxide non-solvent 0.2 ml ethanol 0.2 ml ethanol</td>

<td> t ; 4.</td><td> ____________________&lt;w»__________ (99« Drecioitatinc !™?J? 5 ml human serum liqSd ( ^W albumin (0.1%)</td>

<td></td><td> infusion rate 2.5 ό (ml/min.) of ^άprecipitating liquid</td>

<td> 6.</td><td> stir rate (rev./min) 200 1!nn ~ — of solution ^^uu</td>

<td> . 7.</td><td> temperature of 20’C o_n«r ----- solution ^{zu L}</td>

<td> ' ⁸-</td><td> °'⁵¹θ™ °.⁵</td>

Table lb

<td colspan="2"> Example ר _____________</td><td rowspan="2"> Example _4</td>

<td></td><td> _________________ '־</td>

<td> 1. solid organic compound</td><td> 7 mg RS nitrocellulose (1/4 sec.)</td><td> 10 mg progesterone</td>

<td> 2. organic solvent</td><td> 0.4 ml dimethyl sulfoxide</td><td> 0.2 ml dimethyl sulfoxide</td>

<td> נ non-solvent</td><td> 0.01 ml isopropanol</td><td> 0.2 ml ethanol '(99?)</td>

<td> 4. aqueous precipitating liquid</td><td> 5 ml human serum albumin (0.1?)</td><td> 5 ml human serum albumin (0.1?)</td>

<td> 5. infusion rate (ml/min.) of precipitating liquid</td><td> 2.5</td><td> 2.5 (through an 18 gauge needle</td>

<td> 6. stir rate (rev./min) of solution</td><td> 200</td><td> 200</td>

<td> I. temperature of solution</td><td> 20°C</td><td> 20״C</td>

8. particle 0?5“^οη micron

1. solid organic compound

2. organic solvent

3. non-solvent

4. aqueous precipitating liquid

Table Ic

Example 5

Example

5240 mg iosefamate ethyl ester

1¾ iothalamate ethyl ester ml dimethyl sulfoxide . 32 ml dimethyl sulfoxide ml ethanol (99%)

400 ml polyvinyl pyrrolidone C-15 (5%)

800 ml polyvinyl pyrrolidone C-15 (5?)

5. infusion rate (ml/min.) of precipitating liquid

6. stir rate (rev./min) of solution

300

7. temperature of solution

8. particle . diameter ²⁰’^C . 0-2’C initial

40°C final

1.0 micron 1.0 ^“on

Table Id

Example

Example'

1. solid organic compound

100 mg beta-2,3,6 triod-3-diroethyl formamidino-pheny1 propionic acid ethyl ester

100 mg beta-2,3,6 triod-3-dimethyl fonnamidino-phenyl propionic acid ethyl ester

2. organic solvent

2.0 ml dimethyl sulfoxide

2.0 ml dimethyl sulfoxide

3. non-solvent

2.5 ml ethanol (99%)

2.5 ml ethanol (99?)

4. aqueous precipitating liquid ml Poloxamer 188 25 ml human se™ a poly (oxyethylene- albumin (0 1?) co-oxypropylene) polyner (Pluronic F-68)(0.1£)

5. infusion rate 750 (ml/min.) of precipitating liquid

6. stir rate (rev./min) 650 of solution

7. temperature of 1q״c solution ⁸־ SSter θ'¹⁰‘“״™” 'θ’¹ “⁴⁰׳o'n־

Table le ⁰⁵“P¹⁵ Sample-----

10 2 —־ “

1. solid organic compound

100 mg beta 2,4,6-triiod-

3-dimethyl formamidino phenyl propionic acid ethyl ester

120 mg iodipamide ethyl ester

<td> 2.</td><td> organic solvent</td><td> 2.0 ml dimethyl sulfoxide</td><td> 2.0 ml dimethyl sulfoxide</td>

<td rowspan="2"> 3. 4.</td><td> non-solvent</td><td> . 2.5 ml ethanol (99%)</td><td> 2.5 ml ethanol (99%)</td>

<td> aqueous. precipitating liquid</td><td> 25 ml polyvinyl pyrrolidone C-15 (0.1%)</td><td> 5 ml polyvinyl pyrrolidone C-15 (0.1?)</td>

<td rowspan="2"> 5.</td><td rowspan="2"> infusion rate (ml/min.) of</td><td></td><td></td>

<td> 750</td><td> 300</td>

precipitating liquid

6. stir rate (rev./min) 650 of solution

<td> 7. temperature of solution</td><td> 10*C</td><td> 1 1 1 1 1 1 1 1 1 1 1 1 1 -שן « ¹ O 1 1 1 r 1 i</td>

<td> 8. particle diameter______</td><td> 0.1 micron</td><td> 0.1 micron</td>

Table If

Example

Example

1. solid organic compound

1200 mg iodipamide ethyl ester

120 mg iodipamide ethyl ester

2. organic solvent ml dimethyl sulfoxide

2,0 ml dimethyl sulfoxide

3. non-solvent ml ethanol (99?)

2.5 ml ethanol’ (99%)

4. aqueous precipitating liquid ml polyvinyl pyrrolidone C-15 (0.1%)

5.0 ml polyvinyl pyrrolidone C-15 (0.1?)

5. infusion rate (ml/min.) of ' precipitating liquid

6. stir rate (rev./min) of solution

7. temperature of solution’

10’C

10°c

8. particle diameter

1.5 micron

1.0 micron

Table Ig

Example ___13

Example’

1. solid organic compound

120 mg iodipamide ethyl ester mg isopropyl pyrrolizine derivative (NSC-278214)

2. organic solvent

2.0 ml dimethyl sulfoxide

0.4 ml dimethyl sulfoxide

3. non-solvent

2.5 ml ethanol (99?)

4. aqueous precipitating liquid ml־poly(oxyethylene 5 ml human serum albumin (0.1?) co-oxypropylene) polymer, Poloxamer 188 (Pluronic F-65) (0.1%)

5. infusion rate (ml/min.) of precipitating liquid

6. stir rate (rev./min) of solution

7. temperature of solution

O’C

17°C

8. particle diameter

0.1 micron

0.5 micron

Table Ih ‘ ' ^b* . . , Example Example '

.. .⁶י..... ... ⁵י ...:. .>,־;>

1. solid organic compound 10 mg isopropyl 10 mg isopropyl pyrrolizine pyrrolizine derivative derivative (NSC-278214.) (NSC-278214)

2. organic solvent. 0.4 ml N.N'-dimethyl 0.4 .־ ml dimethyl acetamide sulfoxide

3. non-solvent . .: ’ - ' 0.2 ml ethanol (99%).

4. aqueous precipitating . 20 ml human s,erum 20 ml human serum liquid: . . albumin (0.1%) albumin (0.1%) ׳

5. infusion rate (ml/min.) of precipitating liquid 100 . . 38״

6. stir, rate (rev./min) of solution 50 200

7. temperature of solution^; 0°C 0*C

8. particle diameter. 0.5 micron 0.1 micron

<td colspan="3"> P Table Ij</td>

<td> ' ן</td><td> example ______17</td><td> Example -- 1s</td>

<td> 1. solid organic h compound I___</td><td> 1.5 mg. 1,2 diamino cyclohexane malinate platinum (II)</td><td> 10 mg N-(trifiuoroacetyl) adnomycin 14 valerate</td>

<td rowspan="2"> .I 2. organic J| solvent</td><td></td><td></td>

<td> 0.05 ml phenol</td><td> 0.2 ml dimethyl sulfoxide</td>

<td rowspan="2"> : 3. non-solvent</td><td rowspan="2"> 0.45 ml m-amino phenol and 0.25 ml</td><td></td>

<td rowspan="2"> 0.2 ml ethanol (99?)</td>

<td></td><td> ethanol (99¢)</td>

<td rowspan="2"> 4. aqueous precipitating liquid</td><td> II - W —__</td><td></td>

<td> 5 ml human serum albumin (0.1¢)</td><td> 5 ml human serum albumin (0.1¢)</td>

<td> infusion rate .כ יי, (ml/min.) of</td><td> 5</td><td> 2.5</td>

<td> precipitating liquid</td><td></td><td></td>

<td rowspan="2"> 6. stir rate (rev./min)</td><td></td><td></td>

<td rowspan="2"> 200</td><td> ' _____</td>

<td> • of solution</td><td> 200</td>

<td rowspan="2"> 7. temperature of solution</td><td rowspan="2"> 20°C</td><td></td>

<td> 20°C</td>

particle 0.1 micron 'Ϊ“ή7-⁷־־־־ diameter . ¹.o ®!cron

־

<td> 1</td><td> j: Table Ij</td>

<td> 2 3</td><td>^Exa1?^ple Example-- --------------------------------____________ 20________________</td>

<td> 4</td><td></td>

<td> 5</td><td> ij__ canplex</td>

<td> 6</td><td> ! ²‘ sotont ¹⁰ ”³־ ^isopropano1 θ.2 ml diethyl ’i ____________________ sulfoxide</td>

<td> 7</td><td> 1 3. non-solvent _ ־־ ,. . ₀ ״ 0.2 ml ethanol</td>

<td> 8</td><td> !! ________________________ (99%)</td>

<td> 9</td><td>^h ’’ ^!“luting ²⁰⁰ ״¹״to 5 1״ human־־™, liquid albumin (0.1?)</td>

<td> TO</td><td> 5. infusion rate 37 _{0 c} -----</td>

<td> 11</td><td> (ml/min.) of</td>

<td> 12</td><td> precipitating liquid</td>

<td>¹³</td><td> 6. stir rate (rev./min) 300 oc״ of solution ^טכ</td>

<td> 14</td><td> 7. temperature of 20’C on-r — solution ^b</td>

<td> 15</td><td> — __</td>

<td> 16</td><td> ' ⁸י E£־r °.5 tor. ,.0 micron</td>

<td> 17</td><td> *norethisterone,</td>

<td> 18</td><td> acetyl salicylic acid, wafarin,</td>

<td> 19</td><td> heparin-tridodecyl methyl ammonium chloride complex, sulfamethoxazole, cephalexin,</td>

<td> 20</td><td> prednisolone acetate, diazepam,</td>

<td> 21</td><td> clonazepam, . methidone,</td>

<td> 22</td><td> naloxone, disulfiram,</td>

<td> 23</td><td> mercaptopurine,</td>

<td> 24</td><td> digitoxin, primaquine, mefloquine,</td>

<td> 25</td><td> atropine,</td>

<td> 26</td><td> scopolamine, '. thiazide, furosemide,</td>

<td> 27</td><td> propanelol,</td>

<td> 28</td><td> .: methyl methacrylate, ״ poly methyl methacrylate, 5-fluorodeoxyuridine,</td>

<td> 29</td><td> cytosine arabinoside, acyclovir,</td>

<td> 30</td><td> levonorgestrel</td>

⁵ϋ

6h

I.

7!;

8l.

¹² ?

Example1 ־ to .״ _{show h0}״ _{u־ ρρ0־־־־}produce aqueous dispersions of _a ״_{lde varl־ty ־f}that have low aqueous ,_{01ubUIty a}nd _{f־p ״hl־h ρ־ρ&lt;1־״}ס-- be controlled with substantial precision and predictability. Conditions would be varied ^c varied from compound to compound according to the invention in order to optimize results. This may in some cases include chemical modification ־f the compound to achieve the desired solubility.

Because of the range of examples presented above, it 1־ reasonable to one skilled _{ln th־ apt>}compounds would be expected to behave 1״ ,_{Iallar fa3hl0n}.

Example 20 is also presented in Table I. This example should be performed in tn־ perxormed in the same manner as examples 1 to 19, and would make particles of t-h»

I the listed compounds within the scope of the invention.

Examples 21 to 28 are presented in Table II. !״ each example, the given quantity of lodipamide ethyl ״ter was dissolved in the given volume of dimethyl sulfoxide, then diluted with the given volume of ethanol. The aqueous precipitating liquid was prepared from polyvinylpyrrolidone then infused at the given infusion rate through a needle with the given gauge into the solution while the solution was stirred at the given stir rate. The precipitation was carried out in the given vessel at the^:given temperature. After precipitation, the given amount of saline was added to further stabilize the dispersion. 1״ each example, the mean parti־!־ diameter was about 1.0 micron and substantially uniform.

TABLE Ila

Parameters for Iodipamide Ethyl Ester Particle Precipitation

<td></td><td> Example 21</td><td> ___ Example 22</td><td> Example 23</td>

<td> Material_____</td><td> 0.5 gm______</td><td> 1 g______________</td><td> 2 gin__</td>

<td> iodipamide ethyl ester (60 mg/ml</td><td> 10 ml</td><td> 20 ml</td><td> 40 ml</td>

<td> _____</td><td></td><td></td><td></td>

<td> ethanol (99%)</td><td> • 12.5 ml</td><td> 25 ml</td><td> 50 ml</td>

<td rowspan="2"> polyvinyl</td><td></td><td> ——————— — —---------</td><td></td>

<td rowspan="2"> 25 ml</td><td rowspan="2"> 50 ml</td><td rowspan="2"> 100 ml</td>

<td> pyrrolidone</td>

<td> 0-9? saline</td><td> 15 ml</td><td> 30 ml</td><td> 60 ml</td>

<td> stir rate</td><td> 125 rpm</td><td> 190 rpn</td><td rowspan="2"> 300 rpm</td>

<td rowspan="2"> temperature</td><td></td><td></td>

<td> 4°C</td><td> 4’C</td><td> 4״C</td>

<td> infusion rate</td><td> 11 ml/min</td><td> 19 ml/min</td><td> 30 ml/min</td>

<td> infusion needle size</td><td> 19 g</td><td> 19 g</td><td> 19 g</td>

<td> S.B. length</td><td> 1.5”</td><td> 1.5</td><td> 1.5</td>

<td> vessel diam.</td><td> 2.38”</td><td> 2.38</td><td> 2.38</td>

<td> vessel</td><td> 250 ml</td><td> 250 ml</td><td> 250 ml</td>

<td></td><td> polypropylene bottle</td><td> polypropylene bottle</td><td> polypropylene breaker</td>

6TABLE lib

<td colspan="4"> Parameters for lodipamide Ethyl Ester Particle Precipitation</td>

<td></td><td rowspan="2"> Example 24</td><td rowspan="2"> Example 25</td><td rowspan="2"> ___Example 26</td>

<td></td>

<td> Material</td><td>’5-gP________</td><td> 5 gm</td><td> 10 em</td>

<td> iodipamide ethyl ester (60 mg/ml)</td><td> 70 ml</td><td> 100 ml</td><td> 200 ml</td>

<td> ethanol (99¢)</td><td> 87.5 ml</td><td> 125 ml</td><td> 250 ml</td>

<td> polyvinyl pyrrolidone</td><td> 175 ml</td><td> 250 ml</td><td> 500 ml</td>

<td> 0.9? saline</td><td> 105 ml</td><td> 150 ml</td><td> 300 ml</td>

<td> stir rate</td><td> 330 rpm</td><td> 200 rpm</td><td> 300 rpm</td>

<td> temperature</td><td> —</td><td> —</td><td></td>

<td> infusion rate</td><td> 45 ml/min</td><td> 60 ml/min</td><td> 85 ml/min</td>

<td> infusion needle size</td><td> 19 g</td><td> 18 g</td><td> 18 g</td>

<td> S.B. length</td><td> 1.88</td><td> 2.75</td><td> 2.75”</td>

<td> vessel diam.</td><td> 3.38</td><td> 5.0”</td><td rowspan="2"> 5.0</td>

<td></td><td></td><td></td>

<td> vessel</td><td> 1,000 ml</td><td> 2,000 ml</td><td> 2,000 ml</td>

<td></td><td rowspan="2"> glass beaker</td><td></td><td></td>

<td></td><td> glass beaker</td><td> glass</td>

TABLE lie

Parameters for lodipamide Ethyl Ester Particle Precipitation

<td colspan="2"> ---— ________ Example 27</td><td rowspan="2"> Example 28_________</td>

<td colspan="2"></td>

<td> Material</td><td> 20 gm</td><td> 40 gm</td>

<td> iodipamide ethyl ester (60 mg/ml)</td><td> 400 ml</td><td> 800 ml</td>

<td> ethanol (99%)</td><td> 500 ml</td><td> 1,000 ml</td>

<td> polyvinyl pyrrolidone</td><td> 1,000 ml</td><td> 2,000 ml</td>

<td> 0.9? saline</td><td> 600 ml</td><td> 1,200 ml</td>

<td> stir rate</td><td> 175 rpra</td><td> 210 rftn</td>

<td> temperature</td><td> —</td><td></td>

<td> infusion rate</td><td> 120 ml/min</td><td> 175 ml/min</td>

<td> infusion needle size</td><td> 16 g</td><td> 16 g</td>

<td rowspan="2"> S.B. length</td><td></td><td></td>

<td> 3.25</td><td> 3.25</td>

<td> vessel diam.</td><td> 8.6</td><td> 8.6</td>

<td> vessel</td><td> 9 L</td><td> 9 L</td>

<td></td><td> Bellco vessel________</td><td> Bellco vessel</td>

EXAMPLE 29 ™?^PARATI0N OF IODIPAMIDE ETHYL ESTER PARTICLES FOR ADMINISTRATION TO A PATIENT.

Particles of iodipamide ethyl ester (IDE) with a size of about 1 micron may be prepared for administration to a patient. IDE is the water-insoluble ethyl ester of iodipamide, a water-soluble radiopaque compound used ' clinically for radiographic examination of the gallbladder. The synthesis of iodipamide ethyl ester is known in the art (for example, esterification by alcohol and acid or by a Schotten-Bauman reaction).

IDE is only minimally soluble in water (10“^ m) and can be precipitated easily from the dimethyl sulfoxide (DMS0)/ethanol solvent mixture. However, the simple addition of water to this solution results in IDE particles with extremely rough contours; these particles vary in size from less than one micron to greater than 300 microns in diameter.

In light of the problems that rough contours could damage vascular endothelial cells and promote aggregation, and that large particles could create pulmonary emboli, the method of this invention provides a more refined procedure for controlling particle size and shape.

Particle Precipitation Procedure. Physical methods for modifying and controlling particle size, such as ball milling, grinding or sonication result in preparations with a . very broad range of particle diameters. These methods are , commonly used to eliminate large particles (greater than 4-5 microns) which could embolize in the pulmonary capillary bed, but generally some particles of submicron size are also produced; these very small particles have been shown to be more toxic than 1-2 micron particles, possibly due to • increased protein binding resulting from the much larger : surface area inherent with particles of smaller diameters, or

,. possibly because of excessive uptake by bone marrow cells.

J A chemical precipitation procedure for producing particles of a given size was developed to avoid these problems. By adding an aqueous solution of polyvinyl pyrrolidone, at controlled rates and temperatures, to IDE dissolved in a dimethyl sulfoxide/ethanol solvent, apparently spherical, amorphous particles can be produced with an extremely narrow size distribution. For a particle preparation with a mean diameter of 1 micron, the total range of particle diameters is 0.4 to 2.0 microns with 90 per cent of the particles ranging in size between 0.5 and 1.5 microns, as determined by microscopy.

By carefully controlling precipitation parameters, particle preparations demonstrating different mean diameters, but with a similarly small range of diameters, can be produced.

The IDE particles produced using this methodology are stable in whole blood with little apparent tendency toward aggregation. When suspended in whole blood, there is essentially no tendency for one micron IDE particles to aggregate with themselves or with formed elements of blood. The IDE particles have smooth contours.