Optically pure salts of pyridinylmethosulfinyl-1h-benzimidazole compounds and a pharmaceutical agent containing such salts

The subject of the invention are new compounds with high optical purity and pharmaceuticals containing them.

The compound, 5-methoxy-2- {[(4-methoxy-3,5-dimethyl-2-pyridinyl) methyl] sulfinyl} -1H-benzimidazole with the international name omeprazole and pharmaceutically acceptable basic salts of this compound are described in patent publications European, EP 5129 and EP 124495. Omeprazole and its basic salts are effective inhibitors of gastric acid secretion, useful as anti-ulcer agents. These compounds, which are sulfoxides, have an asymmetric center on the sulfur atom, which means that they exist as two optical isomers (enantiomers). There was a need to obtain compounds with improved pharmacokinetic properties and more favorable metabolism, so that these compounds could have a better therapeutic profile, among others, a lower degree of individual differences in the response of individual patients to the drug. The invention includes such compounds that are new salts of single enantiomers of omeprazole.

Separation of omeprazole enantiomers on an analytical scale is described e.g. in J. Chromatography, 532, 305-319 (1990) and on a preparative scale in the patent specification of the Federal Republic of Germany, DE 4035455. According to this description, the separation is carried out by the use of diastereometric ether, which separates and then hydrolyses in acid solution. Under the acidic conditions required for the hydrolysis of the attached group, omeprazole is unstable, so the acid should be quickly neutralized with alkali to avoid degradation of this acid sensitive compound. In the above-mentioned patent application, this process is carried out by adding a reaction mixture containing concentrated sulfuric acid to a concentrated NaOH solution. This is disadvantageous because it creates a great risk that the pH of the reaction mixture locally reaches a value of 1 to 6, which could be destructive to the substance. In addition, immediate, rapid neutralization produces heat that would be difficult to dissipate in large scale production.

The invention relates to new compounds obtained by a large-scale production process. This method can also be used on a large scale to obtain single enantiomers of omeprazole in neutral form.

No example of an isolated or analyzed salt of optically pure omeprazole, i.e., a single enantiomer of omeprazole, is described in the prior art, neither in the form of an isolated or analyzed salt of any optically pure omeprazole analog.

178 994

The present invention relates to new salts of single enantiomers of omeprazole with Na + or Mg²⁺, i.e., (-) - 5-methoxy-2 - {[(4-methoxy-3,5-dimethyl-2-pyridinyl) methyl] sulfinyl} -1H-benzimidazole salts with Na + or Mg2 +.

The present invention relates to an optically pure salt of (-) - 5-methoxy-2 - {[(4-methoxy-3,5-dimethyl-2-pyridinyl) methyl] sulfinyl} -1H-benzimidazole zNa + or Mg2 +.

A preferred compound of the invention is (-) - 5-methoxy-2- {[(4-methoxy-3,5-dimethyl-2-pyridinyl) methyl] sulfinyl} -1H-benzimidazole magnesium salt.

A preferred compound of the invention is (-) - 5-methoxy-2 - {[(4-methoxy-3,5-dimethyl-2-pyridinyl) methyl] sulfinyl} -1H-benzimidazole sodium salt in crystalline form.

The present invention relates to a pharmaceutical preparation characterized in that it contains an optically pure (-) - 5-methoxy-2 - {[(4-methoxy-3,5-dimethyl-2-pyridinyl) methyl] sulfinyl} -1H-benzimidazole salt with Na + or Mg2⁺as the active substance and a pharmaceutically acceptable carrier.

Particularly preferred salts of the invention are optically pure Na + omeprazole salts of formula I

OCH 3

<img file="PL178994B1_D0001.tif" />

Na +

I (-) - enantiomer and optically pure magnesium salts of omeprazole of formula II

<img file="PL178994B1_D0002.tif" />

II (-) - enantiomer

The expression "optically pure Na + omeprazole salts" means the (-) - enantiomer of omeprazole essentially free of (+) - enantiomer. To date, single enantiomers of omeprazole have been obtained only in the form of syrups and not of crystalline products. According to a specific method for the production of single enantiomers of omeprazole, the salts defined in the invention are easily prepared. In addition, these salts, although not inert, are obtained in the form of crystalline products. It is possible to purify the optically impure salts of omeprazole enantiomers by crystallization, thus they can be obtained with very high optical purity, i.e. with&gt; 99.8 percent enantiomeric excess (ee) even from a preparation contaminated with the second enantiomer. Optically pure salts are also more than solid

178 They are not racemic in both neutral and alkaline pH environments, which is unexpected, since known deprotonation at the carbon atom between the pyridine ring and the chiral sulfur atom should cause racemization under basic conditions. This high stability, i.e. the shoulder of racemization, allows the use of the salts of the single enantiomer of the invention in medicine.

As mentioned above, this method of producing single enantiomers of omeprazole can be used to produce single enantiomers of omeprazole in neutral and salt form.

The compounds of the invention may be used to inhibit gastric acid secretion in mammals, including humans. In a more general sense, the compounds of the invention may be used to treat diseases associated with gastric acid secretion and inflammatory diseases of the digestive system in mammals, including humans, such as gastric ulcer, duodenal ulcer, gastroesophageal reflux disease and gastritis. In addition, these compounds can be used to treat other digestive tract disorders in cases where inhibition of gastric acid secretion is required, thus, in patients treated with nonsteroidal anti-inflammatory drugs, in patients with gastric cancer and in patients with acute upper bleeding. gastrointestinal tract. These compounds may also find application in cases requiring intensive patient care and before and after operations to prevent acidification and ulcers due to stress. The compound of the invention can also be used for the treatment or prevention of inflammation in mammals, including humans, especially those involving liposomal enzymes. These conditions include primarily the primary progressive joint rheumat and gout. The compound of the invention may also be useful in the treatment of psoriasis as well as in the fight against Helicobacter infection

Optically pure compounds of the invention, i.e. single enantiomers, are prepared by reacting a 6-methoxy-2 - {[(4-methoxy-3,5-dimethyl-2-pyridinyl) methyl] sulfinyl} -1- (chloromethyl diastereomeric mixture reaction ) -1H-benzimidazole with mandelic acid, separation of two stereoisomers from the diastereomeric mixture of the following 5 or 6-methoxy-2 - {[(4-methoxy-3,5-dimethyl-2-pyridinyl) methyl] sulfinyl} - compounds 1- [acyloxy-methyl] -1H-benzimidazole of formula IV

OCH 3

<img file="PL178994B1_D0003.tif" />

OAcyl in which the methoxy substituent in the benzimidazole residue is in the 5 or 6 position and in which the Acyl radical is defined as a chiral mandeloil group of the R or S configuration, followed by solvolysis of each separated diastereomer in alkaline solution. The resulting single enantiomers of omeprazole are isolated by neutralizing the aqueous solutions of salts of these single enantiomers of omeprazole with a neutralizing agent, e.g. an acid or ester such as methyl formate.

178 994

Diastereomeric esters can be separated either by chromatography or by fractional crystallization.

Generally, solvolysis is carried out with a base in a protic solvent such as alcohol or water but the acyl group can also be hydrolyzed with a base in an aprotic solvent such as dimethyl sulfoxide or dimethylformamide. As the base, a compound containing an OH group or R'0 'in which R can be used for this reaction¹ is an alkyl or aryl group.

To produce pure Na + salts of the invention, i.e. the Na + salts of individual omeprazole enantiomers, the resulting compound is treated with a base, such as NaOH in an aqueous or non-aqueous medium, or a compound of the formula NaOR²in which R² is an alkyl group having 1-4 carbon atoms or sodium amide, NaNH2. Basic salts may also be prepared in which Li + or K + is present as the cation using the lithium or potassium salts of the above bases, respectively. To obtain the crystalline form of the sodium salt, it is preferred to add NaOH in a non-aqueous medium, e.g. a mixture of 2-butanone and toluene.

In order to obtain the optically pure Mg2 + salts of the invention, the optically pure Na + salts are treated with an aqueous solution of an inorganic magnesium salt, such as MgCl2, resulting in the precipitation of Mg2 + salts. These optically pure Mg2 + salts can also be prepared by treating individual enantiomers of omeprazole with a base, e.g. a base of the formula Mg (OR³) 2, in which R³ is an alkyl group having 1-4 carbon atoms in a non-aqueous solvent such as alcohol (only for alcoholates), e.g., an alcohol of formula ROH or an ether such as tetrahydrofuran. In an analogous manner, it is also possible to produce alkali salts in which Ca 2+ is present as a cation using an aqueous solution of an inorganic calcium salt, e.g. CaCT.

For the purposes of clinical use, these single enantiomers, i.e., optically pure compounds of the invention are prepared in the form of pharmaceutical preparations for oral, rectal, parenteral or other routes of administration. These pharmaceutical preparations contain the individual enantiomers of the invention, generally in combination with a pharmaceutically acceptable carrier. The carrier can be in the form of a solid, semi-solid or liquid diluent or as a capsule. These pharmaceutical preparations are also subject of the invention. Typically, the amount of active compound in the above formulations ranges from 0.1 to 95% by weight of the formulation, with parenteral formulations being from 0.2 to 20% by weight and for formulations for oral administration from 1 to 50% by weight.

In the process of making pharmaceutical preparations in unit dosage forms for oral administration, an optically pure compound is mixed with a solid powdered carrier, such as lactose, sucrose, sorbitol, mannitol, starch, amylopectin, cellulose derivatives, gelatin or other suitable carrier, such as stabilizing substances. as basic compounds, e.g. sodium, potassium, calcium, magnesium or similar carbonates, hydroxides or oxides, and with lubricants such as magnesium stearate, calcium stearate, sodium stearyl fumarate and polyethylene glycol waxes. The resulting mixture is prepared into granules or pressed into tablets. The granules or tablets can be coated with an enteric coating that protects the active compound against acid-catalyzed degradation as long as the drug remains in the stomach. The enteric coating is selected from pharmaceutically acceptable coating materials, e.g. beeswax, shellac or anionic film-forming polymers or similar materials - if appropriate in combination with a suitable plasticizer. Different dyes may be added to the coatings to facilitate differentiation of different amounts of active ingredient in a given dosage form.

Soft gelatin capsules containing a mixture of active compound, vegetable oil, fat or other carrier suitable for soft gelatin capsules may also be prepared. Soft gelatin capsules can also be coated with an enteric coating as described above.

178 994

Hard gelatin capsules may contain granules or enteric coated granules of the active compound. Hard gelatin capsules may also contain the active compound in combination with a solid, powdered carrier such as lactose, sucrose, sorbitol, mannitol, potato starch, amylopectin, cellulose derivatives or gelatin. These capsules may be enteric coated as described above.

Unit forms of the rectal drug may be made in the form of suppositories containing the active substance mixed with a neutral fat base, or they may be prepared in the form of rectal gelatin capsules containing the active substance in a mixture with vegetable oil, paraffin oil or other carrier suitable for use in rectal capsules gelatin. They may also be prepared in the form of ready rectal micro enemas or in the form of dry micro enemas reconstituted by dissolving in an appropriate solvent immediately before use.

Liquid preparations for oral administration may be prepared in the form of syrups or suspensions, i.e. solutions or suspensions containing from 0.2% to 20% by weight of the active ingredient and auxiliaries such as sugar or sugar alcohols and a mixture of ethanol, water, glycerol, glycol propylene and / or polyethylene glycol. If indicated, such liquid preparations may contain coloring, flavoring, saccharin and carboxymethyl cellulose or other thickening agents. Liquid preparations for oral administration may also be prepared in the form of dry powders reconstituted in a suitable solvent before use.

Solutions for parenteral administration may be prepared in the form of solutions of optically pure compounds of the invention in pharmaceutically acceptable solvents, preferably in a concentration from 0.1% to 10% by weight. These solutions may also contain stabilizing and / or buffering agents and may be prepared in the form of ampoules or vials with different unit doses. Solutions for parenteral administration may also be prepared in the form of dry preparations, reconstituted by dissolving in a suitable solvent immediately before use.

The typical daily dose of active compound will depend on various factors, especially the individual needs of the individual patient, route of administration and disease. Generally, oral and parenteral doses will range from 5 mg to 500 mg of active substance / day.

The optically pure omeprazole salts described in the examples change the direction from (+) to (-) optical rotation and vice versa (-) to (+) optical rotation when the sodium salt is produced from the natural form of omeprazole and when the magnesium salt is produced from sodium omeprazole.

Clinical studies A and B were carried out at Astra Hassie AB on pharmaceutical forms of omeprazole, whose chemical name is: 5-methoxy-2 - (((4-methoxy-3,5-dimethyl-2-pyridinyl) methyl) sulfinyl) - 1H-benzimidazole and its enantiomers. The name omeprazole used here refers to the racemic mixture of its (+) and (-) enantiomers, and its enantiomers are designated as (+) - omeprazole and (-) - omeprazole, respectively.

Study A concerns a clinical comparison of the pharmacokinetics of (-) - omeprazole and (+) - omeprazole sodium with the pharmacokinetics of racemic omeprazole sodium and an assessment of the inter-individual difference in relative bioavailability when administered orally to persons with "slow" and "fast" metabolism.

Study B deals with the treatment of patients suffering from gastroesophageal outflow by oral administration of magnesium (-) - omeprazole and the racemic free form of omeprazole, and a comparison of the inhibitory effect of gastric acid secretion measured by duration during elevated intra-gastric pH. Study B also concerns the assessment of inter-individual changes in drug plasma concentrations.

(-) - The omeprazole enantiomer has a surprisingly different and more favorable pharmacokinetic profile in terms of inter-individual differences than both: (+) - the omeprazole enantiomer and omeprazole racemate. This result is contrary to the existing knowledge in this field because

178 994 previously demonstrated that the pharmacodynamic effect in the gastric glands is the same for both enantiomers as would be expected (see Erlandsson et al., Journal of Chromatography, 532 (1990), 305-319 p. 318) because of the mechanism of action of drugs of both enantiomers, a non-chiral active inhibitor is formed in the wall cell compartments at the same rate. The absence of chirality in the active form of omeprazole is a condition rarely seen among chiral drugs where the activity is usually associated with one of the two 'enantiomers' while the other is essentially less active.

Individuals with "slow" and "fast" metabolism

It is known that some individuals (about 3% of Caucasian and about 15% among Asians) have higher (5- or 10-fold) than curves of the mean plasma concentration versus time (AUC). The metabolic capacity of this minority of individuals classified as "slow" or "weak" metabolites (as opposed to most individuals classified as "fast / extensive" or "normal" metabolism) is genetically determined. Omeprazole is mainly metabolised by the CYP2C19 enzyme which exhibits polymophilic activity. The cause of slow metabolism was found to be the inactivity of the main omeprazole metabolizing enzyme: cytochrome P450 (CYP) CYP2C19 isoform. Thus, individuals with "fast" metabolism exhibit CYP2C19 activity, not individuals with "slow" metabolism. This means that the difference in plasma levels of omeprazole in individuals in which the active form of this liver enzyme is expressed and in individuals in which it is not expressed is essential. This leads to some extent to inter-individual differences in drug levels in the total population of people during omeprazole treatment. Thus, there is a multiple difference in plasma drug levels between individuals in which functional enzyme activity is manifested (individuals with "rapid" metabolism) and individuals in which it is not manifested (individuals with "slow" metabolism).

Study A: (-) - Omeprazole in healthy volunteers

The purpose of these studies was to compare the pharmacokinetics of (-) - omeprazole, (+) - omeprazole and racemic sodium. omeprazole after repeated oral administration of 60 mg daily doses of each compound to subjects with "slow" metabolism of omeprazole and 15 mg daily doses of each compound to subjects with "fast" metabolism of omeprazole.

The second goal was to study the effect of various compounds on gastric acid secretion in individuals with "fast" metabolism.

Triple open, random, alternating studies covering three administration periods were performed; the duration of each was 7 days and was followed by a 2 week washout period. Compound plasma levels (pharmacokinetics) were tested in all subjects on Day 1 and Day 7 of each administration period, and the effect on acid secretion was studied in subjects with "rapid" metabolism on Day 7 of each administration period.

The studies were supplemented by taking five individuals with "slow" metabolism (determined by the urine S / R ratio of mephenytoin) and four with "fast" metabolism of omeprazole. Healthy subjects aged 21 to 38 years were examined.

The sodium salts of (-) - omeprazole, (+) - omeprazole and racemic omeprazole, respectively, were administered as drinking solutions (5 mg / ml). In order to neutralize stomach acid in the examined person and thus avoid degradation of acid-labile compounds, a bicarbonate solution was administered along with the drug solution. Further portions of the bicarbonate solution were given to individuals 5 minutes before and at 10, 20 and 30 minutes after dosing.

The mean plasma levels of racemic, single (-) - enantiomer and single (+) - enantiomer omeprazole at steady state (Day 7) in subjects with "fast" metabolism after administration of 15 mg doses of sodium salts of each compound. The steady-state mean concentration-time (AUC) values ​​for (-) - omeprazole are almost 90% higher than for racemic omeprazole, while for (+) - omeprazole they are about one-third compared to racemic omeprazole. Because the gastric acid inhibiting effect is correlated directly with the level of

178 994 mem AUC irrespective of the enantiomeric form of the compound given, this characteristic causes, as shown in Study B, a more pronounced inhibitory effect on gastric acid secretion by (-) - omeprazole than by racemic omeprazole.

The mean plasma levels of racemic, (+) - enantiomer and (-) - enantiomer of steady-state omeprazole (Day 7) in individuals with "slow" metabolism after administration of 60 mg doses of sodium salts of each compound were determined. In subjects with 'slow' metabolism, mean steady-state AUC values ​​for (-) - omeprazole are approximately 30% lower than for racemic omeprazole, while AUC (+) - omeprazole values ​​are higher.

Considering the different dose levels, the AUC for (-) - omeprazole appears to be about 3 times higher in subjects with "slow" metabolism than in subjects with "fast" ("normal") metabolism. On the other hand, for (+) - omeprazole, the differences in AUC between individuals with "slow" and "fast" metabolism are much larger (approximately 30-fold). Racemic omeprazole, which is a mixture of both enantiomers, shows a 10-fold difference in AUC curves between individuals with "slow" and "fast" metabolism. Thus, the ratio in AUC values ​​between individuals with "slow" and "fast" metabolism is much smaller for (-) - omeprazole than for both (+) - omeprazole and racemic omeprazole indicating that (-) - omeprazole is in its metabolism less dependent on CYP2C19 than (+) - omeprazole or racemic omeprazole.

Conclusions from study A * The difference in AUC curves in individuals with "slow" and fast metabolism is only 3-fold for (-) - omeprazole compared to 10- and 30-fold differences for racemic and (+) - omeprazole.

* In subjects with "fast" metabolism, the AUC curve values ​​for (-) - omeprazole are approximately 2 times higher than for racemic omeprazole causing a more pronounced inhibitory effect on acid secretion.

Studies B: (-) - Omeprazole in patients with gastroesophageal reflux

The study was conducted on 38 patients with symptomatic gastroesophageal reflux, who compared the effects of oral administration of 20 mg racemic omeprazole (capsules) and magnesium salt (-) - omeprazole (equivalent to 20 mg or 40 mg of neutral) on 24-hour intra-gastric acidity. In addition, plasma (-) - omeprazole and racemic omeprazole plasma concentrations were determined on the last day of administration (Day 5).

The studies were carried out as double-blind, random, triple alternating administration covering three periods: each lasted five days with daily oral administration of the form containing magnesium (-) - omeprazole or racemic omeprazole and separated by both at least a 2 week washout period. The study involved 38 patients (22 women) aged 29-58 years. 32 patients showed a negative test for Helicobacter pylori.

The hard gelatin capsules were filled with tablets containing (-) - omeprazole magnesium salt and coated with a protective layer against gastric acid so that they correspond to 20 mg or 40 mg of neutral (-) - omeprazole.

The pharmaceutical forms thus prepared were compared, with identical administration, to hard gelatin capsule forms filled with pastilles coated with a gastric acid barrier layer containing 20 mg of racemic omeprazole in the free form of Prilosec® (and not salt).

Intra-gastric pH was recorded for 24 hours for five days for each study after the fifth dose.

Summary of results

Thirty-six patients completed the study, which is why they were developed statistically. The results of drug administration for intragastric pH are summarized in Table 1 and the AUC values ​​are shown in Table 2.

As shown in Table 1, the percentage of time (with a 24-hour evaluation) with a value of H above 4 (a direct measure of the inhibitory effect of gastric acid secretion) was a force of 44% for a 20 mg dose of racemic omeprazole. and 53% for a 20 mg dose of (-) - omeprazole (p &lt;0.0001) which means that for patients given (-) - omeprazole, the time with a H value above 4 in the stomach is 2.2 hours longer than for patients where racemic omeprazole was administered at appropriate doses.

Table 1

Least squares estimates and 95% confidence intervals for the mean values ​​of the feeding effects regarding the percentage of time with a pH value&gt; 4 over 24 hours

<td>Administration</td><td>Estimate</td><td>Lower</td><td>Higher</td>

<td>Omeprazole 20 mg</td><td> 43,7</td><td> 36,7</td><td> 50,7</td>

<td>(-) - omeprazole 20 mg</td><td> 53,0</td><td> 46,0</td><td> 60,0</td>

<td>(+) - omeprazole 40 mg</td><td> 69,8</td><td> 62,8</td><td> 76,8</td>

The data in Table 2 below indicate that the AUC curve values ​​for (-) - omeprazole are significantly higher than for racemic omeprazole at 20 mg doses, and the 40 mg (-) - omeprazole dose gives a higher AUC value than the 20 mg dose ( -) - omeprazole (p &lt;0.0001).

Inter-individual differences in the AUC curves and thus the inhibitory effect is less pronounced when (-) - omeprazole is administered than when racemic omeprazole is administered. This was confirmed by the fact that the coefficients of variation (variation) for mean AUC values ​​are 59% for 20 mg of magnesium salt (-) - omeprazole and 88% for 20 mg of racemic omeprazole (p &lt;0.0001).

Table 2

Least squares estimates and 95% confidence intervals for mean values ​​of the administration effects regarding the percentage of AUC curves (pmol xh / L)

<td>Administration</td><td>Estimate</td><td>Lower</td><td>Higher</td>

<td>Omeprazole 20 mg</td><td> 2,3</td><td> 1,8</td><td> 3,0</td>

<td>(-) - omeprazole 20 mg</td><td> 4,2</td><td> 3,3</td><td> 5,4</td>

<td>(+) - omeprazole 40 mg</td><td> 12,6</td><td> 9,9</td><td> 16,2</td>

Conclusions from Study B * In patients who were administered magnesium (-) - omeprazole, the time with pH above 4 in the stomach was longer as a result of almost two times higher AUC than for racemic omeprazole.

* Significantly smaller differences between individuals were observed in patients given magnesium (-) - omeprazole than in patients given racemic omeprazole.

Clinical implications of test results A and B for administration of (-) - omeprazole as an alkaline salt. A larger group of patients will achieve optimal plasma (-) - omeprazole concentrations.

As a consequence of smaller differences in AUC between patients with "slow" and "fast" metabolism, inter-individual differences in AUC are smaller when using (-) - omeprazole than omeprazole. Furthermore, the available data indicate that the inter-individual differences in the AUC for (-) - omeprazole in the group of subjects with "fast" metabolism are also smaller than observed with racemic omeprazole. Taken together, these characteristics mean that a potentially larger group of patients will achieve plasma (drug) concentrations that are optimal for the desired gastric acid inhibition effect in a clinical situation.

Higher AUC values ​​lead to a better overall clinical effect for (-) - omeprazole.

178 994

It was observed that steady-state AUC for (-) - omeprazole for the average population is significantly higher (2-fold) than for racemic omeprazole if each compound is administered in repeated 20 mg daily doses. Therefore, the inhibitory effect of gastric acid secretion, which is directly related to AUC independent of the compound, is greater for (-) - omeprazole than for racemic omeprazole at identical doses. It is expected that the use of (-) - omeprazole will be clinically more beneficial as more patients are being treated for gastric acid-related disease and a faster recovery time can also be expected. You may also expect a faster resolution of your symptoms.

The clinical studies presented above indicate that the alkali metal (-) - omeprazole salts have the following surprisingly more favorable pharmacokinetic properties than the racemic omeprazole:

* smaller inter-individual differences in plasma drug levels (AUC) equally between individuals with "fast" and "slow" metabolism and in the group of individuals with "fast" metabolism, thus giving a greater number of patients with optimal plasma (drug) concentrations from the point of view of the desired gastric acid inhibition effect, * higher mean AUC values ​​result in a much more pronounced gastric acid inhibition effect and are expected to that this will lead to a better overall clinical effect.

Thus, the (-) - omeprazole alkali salts may be an improved alternative pharmaceutical form used to treat gastric acid related diseases.

The invention is illustrated by the following examples.

Example 1. Preparation of (+) - 5-methoxy-2- {[(4-methoxy-3,5-dimethyl-2-pyridinyl) methyl] sulfinyl} -1 H. -benzimidazole sodium salt

100 mg (0.3 mmol) (-) - 5-methoxy-2 - {[(4-methoxy-3,5-dimethyl-2-pyridinyl) methyl] sulfinyl} -1H-benzimidazole (contaminated with 3% ( +) - isomer) is dissolved in 1 ml of 2-butanone with stirring and 60 ml of 5.0 M aqueous sodium hydroxide solution in 2 ml of toluene are added. The resulting mixture is heterogeneous. To obtain a clear solution, a further portion (about 1 ml) of 2-butanone is added and the mixture is stirred at ambient temperature for 24 hours. The precipitate is filtered off and washed with ether. 51 mg (46%) of the title compound are obtained as white crystals, melting point

246 - 248 ° C (with decomposition). The optical purity (ee) determined by chiral column chromatography is&gt; 99.8%. [and]²⁰D = + 42.8 °. (c = 0.5%, water). NMR data given below.

Example. Preparation of (-) - 5-methoxy-2- {[(4-methoxy-3,5-dimethyl-2-pyridinyl) methyl] sulfinyl} -1H-benzimidazole sodium salt

Quantity 100 mg (0.3 mmol) (+) - 5-methoxy-2 - {[(4-methoxy-3,5-dimethyl-2-pyridinyl) methyl] sulfinyl} -1H-benzimidazole (contaminated with 3% ( -) - isomer) is dissolved in 1 ml of 2-butanone with stirring and 60 ml of 5.0 M aqueous sodium hydroxide solution in 2 ml of toluene are added. The resulting mixture is heterogeneous. To obtain a clear solution, a further portion (about 1 ml) of 2-butanone is added and the mixture is stirred at ambient temperature for 24 hours. The precipitate is filtered off and washed with ether. 56 mg (51%) of the title compound are obtained as white crystals, melting point

247 - 249 ° C (with decomposition). The optical purity (ee) determined by chiral column chromatography is&gt; 99.8%. - [α]²% = -44.1 °. (c = 0.5%, water). NMR data are given below.

Example III. Preparation of (+) - 5-methoxy-2- {[[4-methoxy-3,5-dimethyl-2-pyridinyl) methyl] sulfinyl} -1H-benzimidazole magnesium salt

To 0.10 g (0.29 mmol) of (+) - 5-methoxy-2 - {[(4-methoxy-3,5-dimethyl-2-pyridinyl) methyl] sulfinyl} -1H-benzimidazole is added 21 , 9 ml OJ M NaOH solution. To the resulting mixture, 2 mL of methylene chloride is added, and after shaking in a separatory funnel, the aqueous solution is separated and 14 mg of MgClC solution in water (0.145 mmol) are added dropwise. The precipitate is isolated by centrifugation and 52 mg (50%) of the product is isolated as an amorphous powder. The optical purity (ee) of the product is 98% and is the same as the optical purity of the starting material. Optical purity was determined by chromatography on an analytical chiral column. [α]²⁰ο = + 101.2 °. (c = 1%, methanol). The Mg content in the sample determined by atomic absorption spectroscopy is 3.0%.

Example IV Preparation of (+) - 5-methoxy-2- {[(4-methoxy-3,5-dimethyl-2-pyridinyl) methyl] sulfinyl} -1H-benzimidazole magnesium salt

The amount of 0.500 g (1.36 mmol) of sodium (-) - 5-methoxy-2 - {[(4-methoxy-3,5-dimethyl-2-pyridinyl) methyl] sulfinyl} -1H-benzimidazole is dissolved in 10 ml of water and 10 ml of an aqueous MgCl2 x H2O solution (138 mg, 0.68 mmol) are added dropwise and the precipitate is isolated by centrifugation. 418 mg (86%) of the product are obtained in the form of a white powder. The optical purity (ee) of the product is 99.8% and is the same as the optical purity of the starting material. Optical purity was determined by chromatography on an analytical chiral column. [Ra] 2⁽⁾0 = + 129.9 ° (c = 1%, methanol).

Example V. Preparation of (-) - 5-methoxy-2- {[[4-methoxy-3,5-dimethyl-2-pyridinyl) methyl] sulfinyl} -1H-benzimidazole magnesium salt

The amount of 0.165 g (0.45 mmol) of sodium (+) - 5-methoxy-2 - {[(4-methoxy-3,5-dimethyl-2-pyridinyl) methyl] sulfonyl} -1H-benzimidazole is dissolved in 3 ml water and 2 ml aqueous MgCl solution are added dropwise₂ x H2O (46 mg, 0.23 mmol) and the precipitate is isolated by centrifugation. 85 mg (51%) of the product are obtained in the form of a white powder. The optical purity (ee) of the product is 99.9% and is the same or higher as the optical purity of the starting material. Optical purity was determined by chromatography on an analytical chiral column. [A] 20_D = -128.2 ° (c = 1%, methanol).

Example Solvent NMR data (δ ppm)

DMSO-d₆500 MHz

DMSO-d, 500 MHz

II

2.00 (s, 3H), 2.22 (s, 3H), 3.99 (s, 3H),

3.72 (s, 3H), 4.37 (d, 1H), 4.75 (d, 1H),

6.54 (dd, 1H), 6.96 (d, 1H), 7.30 (d, 1H),

8.21 (s, 1H).

2.20 sso 3H ,, 2.22 s ,, 3H), 3.69, 3H),

3.72 (s, 3H), 4.38 (d, 1H), 4.73 (d, 1H),

6.54 (dd, 1H), 6.96 (d, 1H), 7.31 (d, 1H),

8.21 (s, 1H).

The production of synthetic intermediates is described in the following examples.

Example VI. Preparation of 6-methoxy-2- {[(4-methoxy-3,5-dimethyl-2-pyridinyl) methyl] - (R / S) -sulfinyl] -1 - [(R) -mandeoyloxymethyl] -1H-benzimidazole

A solution of 3.4 g of sodium hydroxide in 40 ml of water is added to a mixture of 14.4 g (42 mmol) of tetrabutylammonium bisulfate and 6.4 g (42 mmol) of (R) - (-) mandelic acid. The mixture is extracted with 400 ml of chloroform. After separation of the layers, the organic extract is boiled with a total of 16.6 g (42 mmol) of racemic 6-methoxy-2 - {[(4-methoxy-3,5-dimethyl-2-pyridinyl) methyl] sulfinyl} - 1- (chloromethyl) -1H-benzimidazole. After evaporation of the solvent, the residue is diluted with 100 ml of dichloromethane and 700 ml of ethyl acetate. The mixture is washed three times with 200 ml of water and the organic solution is dried over MgSO₄ and evaporates. The crude product is purified by recrystallization from 100 ml acetonitrile to give 8.1 g of the title compound (38%) as a mixture of diastereomers. NMR analysis data are given below.

Example VII. Isolation of the more hydrophytic 6-methoxy-2- {[[4-methoxy-3,5-dimethyl-2-pyridinyl) methyl] - (R / S) -sulfinyl} -1 - [(R) -mandeloyloxymethyl] -1H diasteromer benzimidazole

The diastereomers of the title compound of Example 6 are separated by reverse phase HPLC. About 300 mg of the diastereomeric mixture is dissolved in 10 ml of hot acetonitrile and diluted with 10 ml of a mixture of 0.1 M aqueous ammonium acetate and acetonitrile (70/30). The solution is applied to the column and the compounds are eluted with a mixture of 0.1 M aqueous ammonium acetate and acetonitrile (70/30). Isomer of bar12

178 994 more hydrophilic is easier to obtain in pure form than the less hydrophilic isomer. The further procedure for processing the fraction containing the pure isomer is as follows: extraction with dichloromethane, washing the organic solution with a 5% aqueous solution of sodium bicarbonate, drying over Na₂SO₄ and evaporation of the solvent on a rotary evaporator (removal of acetonitrile is facilitated by the addition of dichloromethane at the end of evaporation). Starting from 1.2 g of the diasteromeric mixture and following the above procedure, 410 mg of the more hydrophyte isomer in the pure state is obtained in the form of a colorless syrup. NMR data are given below.

Example VIII. Preparation of 6-methoxy-2 - {[(4-methoxy-3,5-dimethyl-2-pyridinyl) methyl] - (R / S) -sulfmyl} -1 - [(S) -mandeloyloxymethyl] -1H-benzimidazole

The product is prepared starting from 8.1 g (202 mmol) of sodium hydroxide in 100 ml of water, 34.4 g (101 mmol) of tetrabutylammonium hydrogen sulfate, 15.4 g (101 mmol) of (S) - (+) mandelic acid and 39.9 g (101 millimoles) of racemic 6-methoxy-2 - {[(4-methoxy-3,5-dimethyl-2-pyridinyl) methyl] - (R / S) sulfinyl} -1- (chtoromethite) -1H benzimidazole. The procedure described in example VI shall apply. Recrystallization from 100 ml of acetonitrile gives 21.3 g (41%) of the title compound as a diastereomeric mixture. NMR analysis data are given below.

Example IX. Isolation of the more hydrophyte diastereomer of 6-methoxy-2- {[(4-methoxy-3,5-dimethyl-2-pyridinium) methyl) - (R / S) -sulfinyl} -1 - [(S) -mandeloyloxymethyl] -1H benzimidazole

The diastereomers of the title compound of Example VIII are separated by reverse phase chromatography and HPLC in the same manner as in Example VII, starting from a diastereomeric mixture of 6-methoxy-2- {[(4-methoxy-3,5-dimethyl-2- pyridinyl) methyl] - (R / S) -sulfinyl} -1 - [(S) -mandeloyloxymethyl] -1H-benzimidazole instead of the ester with (R) -maldic acid, as in Example VII. From 2.1 g of the diastereomeric mixture, 760 mg of the more hydrophyte compound is obtained in pure form as a colorless syrup. NMR data are given below.

Example X. Preparation of (-) - 5-methoxy-2 - {[i4-methoxy-3,5-dimeth- to 2-pyridinyl) methylsulfinyl} -1H-benzimidazole

Amount of 0.23 g (0.45 mmol) of the more hydrophyte diastereomer of 6-methoxy-2 - {[(4-methoxy-3,5-dimethyl-2-pyridinyl) methyl] sulfinyl} -1 - [(R) -methylthoxymethyl ] -1H-benzimidazole is dissolved in 15 ml of methanol, a solution of 36 mg (0.9 mmol) of sodium hydroxide in 0.45 ml of water is added and after 10 minutes the mixture is evaporated on a rotary evaporator. The residue is partitioned between layers of 15 ml water and 15 ml dichloromethane. The organic solution is extracted with 15 ml of water and 85 pl (1.4 mmol) of methyl formate are added to the combined aqueous solutions. After 15 minutes, the mixture is extracted with dichloromethane (3x10 mL). The organic solution is dried over Na₂SO₄ and evaporates. 0.12 g (77%) of the title compound is obtained in the form of a colorless syrup. The optical purity (ee) analyzed by chiral column chromatography is 94%. [A] 2 °_D = -155 ° (c = 0.5%, chloroform). NMR data are given below.

Example XI. Manufacture (⁺) -5-methoxy-2 - {[(4-methoxy-3.5-dimethyl-2-pyridinyl) methyl sulfinyl} -1H-benzimidazole

Amount of 0.76 g (1.5 mmol) of the more hydrophyte 6-methoxy-2 - {[(4-methoxy-3,5-dimethyl-2-pyridinyl) methyl] sulfinyl} -1 - [(S) -mandeloyloxymethyl diastereomer ] -1H-benzimidazole is dissolved in 50 ml methanol, a solution of 0.12 mg (3.0 mmol) sodium hydroxide in 1.5 ml water is added and after 10 minutes the mixture is evaporated on a rotary evaporator. The residue is partitioned between layers of 25 ml water and 25 ml dichloromethane. The organic solution is extracted with 25 ml of water and 200 pl (3.2 mmol) of methyl formate are added to the combined aqueous solutions. After 15 minutes, the mixture is extracted with dichloromethane (3 x 25 mL). The organic solution is dried over Na2SO4 and evaporated. receives

178 994 yielded 0.42 g (81%) of the title compound as a colorless syrup. The optical purity (ee) analyzed by chiral column chromatography is 98%. [Α]²⁰ο = + 157 ° (c = 0.5%, chloroform). NMR data are given below.

Table 3

<td>Example</td><td>Solvent</td><td>NMR data (δ ppm)</td>

<td>VI</td><td>500 MHz CDCl3</td><td>2.18 (s, 3H), 2.20 (s, 3H), 2.36 (s, 3H), 2.39 (s, 3H), 3.77 (s, 3H), 3.78 (s , 3H), 3.82 (s, 3H), 3.87 (s, 3H), 4.80 (d, 1H), 4.88 (d, 1H), 5.0 (m, 2H), 5 , 34 (s, 2H), 6.43 (d, 1H), 6.54 (d, 1H), 6.6 - 6.7 (m, 2H), 6.90 (d, 1H), 6, 95-6.98 (m, 2H).</td>

<td>VII</td><td>500 MHz CDCl3</td><td>2.20 (s, 3H), 2.36 (s, 3H), 3.78 (s, 3H), 3.82 (s, 3H), 4.80 (d, 1H), 5.00 (d , 1H), 5.35 (d, 1H), 6.43 (d, 1H), 6.63 (d, 1H), 6.90 (d, 1H), 6.97 (dd, 1H), 7 , 2 - 7.3 (m, 3H), 7.37 (m, 2H), 7.62 (d, 1H), 7.97 (s, 1H).</td>

<td>VIII</td><td>500 MHz CDClj</td><td>2.19 (s, 3H), 2.20 (s, 3H), 2.36 (s, 3H), 2.39 (s, 3H), 3.77 (s, 3H), 3.78 (s , 3H), 3.83 (s, 3H), 3.87 (s, 3H), 4.80 (d, 1H), 4.88 (d, 1H), 5.0 (m, 2H), 5 , 34 (s, 2H), 6.43 (d, 1H), 6.54 (d, 1H), 6.6 - 6.7 (m, 2H), 6.90 (d, 1H), 6, 96 - 6.98 (m, 2H), 7.01 (d, 1H), 7.2 - 7.3 (m, 6H), 7.37 (m, 2H), 7.58 (d, 1H) , 7.62 (d, 1H), 7.95 (s, 1H), 7.97 (s, 1H).</td>

<td>IX</td><td>500 MHz CDClj</td><td>2.20 (s, 3H), 2.36 (s, 3H), 3.78 (s, 3H), 3.82 (s, 3H), 4.80 (d, 1H), 5.00 (d , 1H), 5.35 (d, 1H), 6.43 (d, 1H), 6.63 (d, 1H), 6.90 (d, 1H), 6.97 (dd, 1H), 7 , 2 - 7.3 (m, 3H), 7.37 (m, 2H), 7.62 (d, 1H), 7.97 (s, 1H).</td>

<td>X</td><td>500 MHz CDCl3</td><td>2.18 (s, 3H), 2.22 (s, 3H), 3.68 (s, 3H), 3.83 (s, 3H), 4.77 (m, 2H), 6.93 (dd , 1H), 7.0 (b, 1H), 7.5 (b, 1H), 8.19 (s, 1H)</td>

<td>XI</td><td>500 MHz CDClj</td><td>2.21 (s, 3H), 2.23 (s, 3H), 3.69 (s, 3H), 3.84 (s, 3H), 4.76 (m, 2H), 6.94 (dd , 1H), 7.0 (b, 1H), 7.5 (b, 1H), 8.20 (s, 1H)</td>

The best currently known method of carrying out the invention is the use of sodium salts of optically pure compounds, i.e. the compounds of Example 1 and Example 2.

Pharmaceutical preparations containing the compounds according to the invention as the active substance are illustrated by the following recipes.

Syrup

A syrup containing 1% (w / v) active substance is made from the following ingredients:

<td>Relationship with example II</td><td>1.0 g</td>

<td>Ground Sugar</td><td>30.0 g</td>

<td>Saccharin</td><td>0.6 g</td>

<td>Glycerol</td><td>5.0 g</td>

<td>Fragrance</td><td>0.05 g</td>

<td>Ethanol 96%</td><td>5.0 g</td>

<td>Distilled water,</td><td></td>

<td>qs to final volume</td><td>100 ml</td>

Sugar and saccharin are dissolved in 60 g of warm water. After cooling to a sugar solution and glycerol

<td colspan="3">the active ingredient is added and then a solution of the fragrances dissolved in ethanol. The mixture is diluted with water to a final volume of 100 ml.</td>

<td>Enteric coated tablets</td><td></td><td></td>

<td colspan="3">Tablets with an enteric coating containing 50 mg of active ingredient are prepared from the following:</td>

<td>Puffing ingredients:</td><td></td><td></td>

<td>1. The compound of Example 3</td><td></td><td></td>

<td>in the form of magnesium salt</td><td> 500</td><td>g</td>

<td>Lactose</td><td> 700</td><td>g</td>

<td>methylcellulose</td><td> 6</td><td>g</td>

<td>Cross-linked polyvinylpyrrolidone</td><td> 50</td><td>g</td>

<td>Magnesium Stearate</td><td> 15</td><td>g</td>

178 994

<td>Sodium carbonate</td><td>6 g</td>

<td>Distilled water</td><td>qs</td>

<td>2. Cellulose acetate phthalate</td><td>200 g</td>

<td>Cetyl alcohol</td><td>15 g</td>

<td>isopropanol</td><td>2200 g</td>

<td>Methylene chloride</td><td>2000 g</td>

<td>1. The compound of Example 3 in:</td><td>the powder form is mixed with lactose and granulated with aqueous</td>

methyl cellulose and sodium carbonate solution. The wet mass is rubbed through a sieve and the granulate is dried. After drying, the granulate is mixed with polyvinylpyrrolidone and magnesium stearate. Tablet cores (10,000 tablets) are pressed from the dry mix in a tablet press with a 7 mm punch diameter. Each tablet contains 50 mg of active substance.

2. The tablets from item 1 are sprayed with a solution of cellulose acetate phthalate and cetyl alcohol in a mixture of isopropanol and methylene chloride in an Accela Cota Manesty coating apparatus. The final tablet weight is 110 mg.

Solution for intravenous administration

A solution for intravenous administration containing 4 mg of active compound per ml is prepared from the following ingredients.

Compound of Example II 44

Sterile water up to a final volume of 1000 ml

The active ingredient dissolves in such an amount of water as to obtain 1000 ml of solution. This solution is filtered through a 0.22 pm filter and immediately poured into sterile ampoules. The filled ampules are sealed.

capsules

Capsules containing 30 mg of active compound are made from the following ingredients:

<td>Relationship with Example 1</td><td>300 g</td>

<td>Lactose</td><td>700 g</td>

<td>Microcrystalline cellulose</td><td>40 g</td>

<td>Low hydroxypropyl cellulose</td><td></td>

<td>degree of substitution</td><td>60 g</td>

<td>Disodium phosphate</td><td>2 g</td>

<td>Purified Water</td><td>q.^s.</td>

<td colspan="2">The active ingredient is mixed with dry ingredients and granulated by adding a phosphate solution</td>

disodium. The wet mass is extruded in an extruder, spheronized and dried in fluidized dries.

The 500 g pellets produced are initially coated with a solution of 30 g hydroxypropyl methylcellulose in 750 g water in a fluidized bed coating apparatus. After drying, the pellets are coated with a second coating of the composition given below:

Coating solution:

Hydroxypropyl methylcellulose phthalate 77 g

Cetyl alcohol 4 g

Acetone 200 g

Ethanol 600 g

The capsules thus coated are filled into capsules.

suppositories

Suppositories are made by melting using the following ingredients. Each suppository contains 40 mg of active compound.

Compound of example II 4 g

WitepsolH-15 110 g

The active ingredient is homogenized with Witepsol H-15 at 41 ° C. The molten mass is filled into prefabricated suppository packs in the amount needed to obtain a net weight of 1.04 g. After the mass has cooled, the packs are sealed hot. Each suppository contains 40 mg of active ingredient.

178 994

Stability in terms of racemization at different pH values

The stability of the optically pure compounds of the present invention in terms of racemization was tested at low concentrations in a refrigerator in aqueous buffered solutions at pH 8,9,3,10 and 11.2. Stereochemical stability was measured by comparing the optical purity of the (-) - 5-methoxy-2 - {[(4-methoxy-3,5-dimethyl-2-pyridinyl) methyl] sulfinyl} -1H-benzimidazole isomer in a buffer solution immediately after dissolution and after a few days. The measurement was carried out by chromatography on an analytical chiral column. An example of the unexpectedly high stereochemical stability of the compounds of the invention under alkaline conditions is the fact that no racemization of the test compound at pH 11.2 was found even after 21 days. At a pH of 8, 9.3 and 10, chemical degradation of the compound becomes more apparent, which hinders the measurement of the degree of racemization, but no detectable racemization was found after 16 days at any pH tested.

In another experiment on racemization of optically pure compounds prepared according to the invention, an aqueous phosphate buffered solution (pH = 11) (+) - the 5-methoxy-2 - {[(4-methoxy-3,5-dimethyl-2-pyridinyl) isomer) methyl] sulfinyl} -1H-benzimidazole (c = 10⁵M) was kept at 37 ° C for 26 hours and no racemization was observed.

178 994

UPRP Publishing Department Price PLN 4.92 (including 23% VAT)