SI21748A - Inclusion complexes of clopidogrel and its acidic addition salts, procedure of their preparation, pharmaceutical preparations containing these complexes and their application for treatment of thrombosis - Google Patents

Abstract

The submitted invention deals with inclusion complexes of clopidogrel and its acidic addition salts with polymeric compounds, preferentially beta, gamma and eta cyclodextrins and their methylated and hydroxyalkylated derivatives, with the procedure of their preparation and their application for treating atherosclerosis and thrombosis.

Description

Inclusion complexes of clopidogrel and its acid addition salts, method for their preparation, pharmaceutical preparations containing these complexes and their use for the treatment of thrombosis.

FIELD OF THE INVENTION

The invention relates to the pharmaceutical industry and relates to new inclusion complexes of clopidogrel and its acid addition salts, preferably clopidogrel hydrocenesulfate and hydrochloride with polymeric compounds, preferably cyclodextrins.

A technical problem

Clopidogrel hydrogensulfate is a pure optically active (+) form of clopidogrel having one asymmetric C atom, therefore the compound is chemically sensitive and isomerization and formation of the less active compound can occur in the protic solvents. In addition, the ester bond is also sensitive to hydrolysis.

The compound can occur in several different polymorphic crystalline forms, differing in their stability, physical properties, characteristic spectra and solubility. The most common addition salt of clopidogrel is hydrogen sulphate, and hydrochloride is also known.

Despite the relatively high solubility in water (> 20 g / 100 ml of water), the dissolution of clopidogrel hydrogensulfate is problematic: dissolution is very uneven in neutral or even slightly acidic media (pH 5). Typically, the substance is hydrophobically adhered to the walls or surfaces. to the environment and one part does not dissolve in any way in water, even with prolonged mixing. Contact with ordinary, calcium-containing hard water immediately results in a solution clouding when calcium sulphate (insoluble) and clopidogrel base (insoluble) form from clopidogrel hydrogen sulphate. This phenomenon may lead to inaccuracies in the dosage of the compound in the pharmaceutical preparation.

For these reasons, it would make sense to include the clopidogrel molecule in a new complex form that would provide better dissolution, greater stability and more accurate dosing.

The state of the art

Clopidogrel is a generic name for methyl - (+) (S) -a- (2-chlorophenyl) -6,7-dihydrothieno [3,2c] pyridine -5 (4H) -acetate of the formula:

Therapeutic preparations usually contain this active substance in the form of hydrogen sulphate, usually containing a tablet of 98 mg of clopidogrel hydrogen sulphate, equivalent to 75 mg of clopidogrel base.

Clopidogrel hydrogensulfate is an antithrombotic substance that dramatically improves atherosclerosis and prevents myocardial infarctions or heart attacks. Recent studies have shown that clopidogrel is more effective than blood aspirin in preventing blood clots, and more particularly, milder for the gastrointestinal tract. It is also more effective than aspirin at lower doses.

Clopidogrel was first described and protected in EP 99.802, US 4,529,596 (1984 - by Sanofi).

The preparation of the (+) form of clopidogrel hydrogen sulphate was described in European patent EP 281.459; US 4,847,265 (1988, Sanofi). This patent also protects clopidogrel hydrogensulfate in polymorphic form 1. It has been discovered that this salt may exist in different polymorphic crystalline forms, differing in stability, physical properties, spectra and, of course, in the process of their preparation.

Thus, US Patent Nos. 6,504,030 B1 and US 6,429,210B1 describe polymorph Form 2.

PCT patent WO 03 / 051362A2 (TEVA, 2003) discloses polymorphic forms 1 to 6 and amorphous form.

The preparation of various polymorphic crystalline forms of clopidogrel hydrogen sulphate from 1 to 6 and the amorphous form is also disclosed in U.S. Patent Application US 2003 / 0114479A1.

In PCT application WO 03 / 066637A1 Egis (Hungary) protects the new addition salt of clopidogrel hydrochloride in crystalline forms 1 and 2 and the process for their preparation.

From the patent of Sl 9300199A, the improvement of the solubility of 1,4-dihydropyridines by the use of cyclodextrin complexes is known.

Patent Sl 8810082A8 discloses a process for the preparation of a nicardipine inclusion complex with beta-cyclodextrin that increased the solubility of the active substance.

J. Szeitli, Cyclodextrins and their Inclusion Complexes, Akademiai Kiado, Budapest, 1982 The literature deals with inclusion complexes of many active substances with various cyclodextrins.

Cyclodextrins are also known to form inclusion complexes with other molecules of suitable size and polarity (J.Pharm. Sci. 64, 1585, 1975). Cyclodextrins are cyclic compounds composed of 6 - 8 glucopyranoside units. In addition to the cylindrical structure, they are characterized by a special arrangement of hydroxyl units on the outside of the molecule, which is therefore hydrophilic, while the interior is lipophilic. Therefore, less polar active ingredient molecules (guest molecules) like to bind inside the cyclodextrin cylinder. However, they must be of suitable dimensions. Thus, these guest molecules are significantly better protected from external influences.

Description of solution to a technical problem

The present invention provides novel inclusion complexes of clopidogrel and its acid addition salts with cyclodextrins or. other polymeric substances. The new inclusion complexes have excellent, almost unlimited solubility in water, without any partial dissolution and bonding of the substance to the walls as with clopidogrel hydrogen sulphate. These complexes dissolve in water in an instant and 100% and there are no distribution problems.

From the range of different cyclodextrins, α, β, γ and η cyclodextrins can be used, and in particular their methylated and hydroxy-alkylated derivatives, which are even significantly better in solubility.

Instead of cyclodextrins, other polymeric compounds known for the preparation of pharmaceutical forms may also be used. For example, various polyvinylpyrrolidones with molecular weights between 10,000 and 40,000. In this way, clopidogrel and its addition salts also integrate nicely into the polymer structure.

The process for the preparation of inclusion complexes is carried out by first preparing an aqueous or aqueous / alcoholic solution of cyclodextrin or other polymeric substance, for example polyvinylpyrrolidone, and then adding the calculated amount of clopidogrel base and an equivalent amount of the corresponding acid to form the anion. The solution was stirred for one to three hours for the molecules in the complex to settle and then dried in an appropriate manner. For drying, any method can be used to remove the solvent from a solution that does not damage the complex formed. Preferably, lyophilization or spray drying in hot air flow is used. Alternatively, the solvent can be evaporated at a slightly elevated vacuum temperature.

Alternatively, prepare the inclusion complex with clopidogrel in one solvent and then precipitate it with another solvent in which it is insoluble.

The process of preparation of inclusion complexes of clopidogrel or. of its addition salts is similar for all cases where cyclodextrins, their methylated and hydroxyalkylated derivatives or various polyvinylpyrrolidones are used. We use different component ratios, preferably taking from 10 to 50% of clopidogrel or addition salt by weight of the complex.

The content of clopidogrel in inclusion complexes is demonstrated by HPLC analysis under the same conditions as for the determination of free clopidogrel hydrogen sulphate. The conditions are given in Embodiment 6. An example of the determination is shown in Figure Fig.1. Chromatogram A refers to free clopidogrel hydrogen sulfate and chromatogram B to its inclusion complex containing 25% of the active substance in (2-hydroxypropyl) β-cyclodextrin.

NMR spectrum of Fig. 2 (recorded at 300 MHz in D ₂ O) is a spectrum of pure clopidogrel hydrogen sulphate and shows characteristic signals at 3.8 ppm (singlet, s), 5.85 ppm (s), 6.7 ppm (doublet, d) and 7 , 3 - 7.7 (multiplet, m). The signal at 4.8 ppm was generated by proton exchange with D ₂ O.

NMR spectrum of the host compound - (2-hydroxypropyl) -beta-cyclodextrin in FIG. 3. shows typical signals at 1.13 ppm (d), from 3.4 - 4.1 ppm (multiple multiplets), 5.1 ppm (wide s) and 5.25 ppm (wide s).

The NMR spectrum of the inclusion complex of clopidogrel hydrogen sulphate in (2hydroxypropyl-beta-cyclodextrin in Figure Figure4 4) demonstrates the presence of both components in the polymeric structure.

IR spectra attached to the figures Figs. 5, 6, 7 and 8 are recorded in a KBr tablet.

The spectrum in Fig. 5. Represents pure crystalline clopidogrel hydrogen sulfate with a very characteristic signal at 1752 cm &^lt; ^-1 &^gt;.

The IR spectrum of FIG. 6. represents a mechanical mixture of clopidogrel hydrogen sulphate (27% content) and (2-hydroxypropyl) -beta-cyclodextrin. The absorption bands of both components of the mixture are visible, including the characteristic band at 1752 cm ¹ .

The IR spectrum of FIG. 7. represents the inclusion complex of clopidogrel hydrogen sulfate containing 27% in (2-hydroxypropyl) -beta-cyclodextrin. The absorption band at 1752 cm ¹ is visible but significantly less pronounced than in the mechanical mixture of the two components, indicating that the clopidogrel hydrogen sulphate molecule is immobilized inside the polymer structure and shaded. Some other absorption bands are also different.

The IR spectrum of FIG. 8. represents pure (2-hydroxypropyl) -beta-cyclodextrin.

In determining the melting point, we found that the melting ranges of inclusion complexes differ from the values for crystalline clopidogrel hydrogen sulphate and (2hydroxypropyl) -beta-cyclodextrin alone, or the same for other cyclodextrins. We found out that we are not dealing with a simple mechanical mixture of components. Melting points were determined with a Kofler microscope and are not corrected.

Clopidogrel Hydrogensulfate ................................................ ......... 184 - 188 ° C

Mechanical mixture of both components .......................... partly at 182-187 ° C completely at 205-210 ° C (2-hydroxypropyl) -beta-cyclodextrin .............................................. ..> 290 ° C

Inclusion complex (27%) in (2-hydroxypropyl) -beta-cyclodextrin. 190 - 200 ° C

In inclusion complexes, no melting point is observed in the range of free crystalline clopidogrel hydrogen sulphate, but the melting point is usually higher and less sharp, but certainly lower than the basic cyclodextrin from which we derived.

For some preparation methods, for example by solvent evaporation or precipitation, the melting point of the complex may also be lower than the melting points of the two individual components.

Thermal developments in the heating of inclusion complexes are also indicated by DSC thermograms recorded on SDT 2960, TA Instruments Inc.

The thermogram of Fig. 9. is characteristic of free crystalline clopidogrel hydrogen sulphate, where the major change in the melting point of the substance is 184 ° C.

The thermogram in Fig. 10. indicates a mechanical mixture of both components of the inclusion complex (active ingredient content 27%), where the melting point of clopidogrel hydrogen sulphate at 182 ° C is visible.

The thermogram in Fig. 11. is characteristic of an inclusion complex with 27% clopidogrel hydrogen sulphate in (2-hydroxypropyl) -beta-cyclodextrin, where the melting point of the active substance is no longer visible.

Also in the thermogram in Fig. 12. for the inclusion complex with 27% of clopidogrel hydrogen sulphate in methyl-beta-cyclodextrin, no thermal changes accompanying the melting of clopidogrel hydrogen sulphate in the range 182-184 ° C are seen.

From the IR spectra and thermograms discussed, it can be concluded that clopidogrel is in a different chemical bond in these complexes.

X-ray powder diffractograms were recorded on a Siemens D 5000 diffractometer using a reflection technique under the following conditions: CuKa radiation, range 2 ° - 37 °, step 0.04 °, integration time 1 sec.

The diffraction pattern of FIG. 13 for clopidogrel hydrogen sulfate indicates a distinct crystalline structure. In the diffraction pattern of FIG. 14 for the mechanical mixture of clopidogrel hydrogen sulphate and (2-hydroxypropyl) -beta-cyclodextrin are still visible reflexes not characteristic of crystalline clopidogrel hydrogen sulphate.

But the diffraction pattern in Fig. 15 from the inclusion complex with 27% clopidogrel hydrogen sulphate in the matrix of (2-hydroxypropyl) -beta-cyclodextrin and also the diffractogram in Fig. 16 of the inclusion complex with 25% clopidogrel hydrogen sulphate in methyl-β-cyclodextrin show no crystal structure. Inclusion complexes are therefore amorphous compounds, which is also expected in view of their preparation.

These spectral and thermal studies confirm that the inclusion complexes of clopidogrel and its acid addition salts with cyclodextrins are novel complex compounds and are by no means merely a mechanical mixture of components.

The invention also relates to pharmaceutical preparations having antithrombotic and anti-sclerotic activity, containing a therapeutically effective amount of the inclusion complex, together with pharmaceutically acceptable carriers and other excipients.

Suitable pharmaceutical formulations are solid dosage forms, such as tablets with immediate or delayed release of the active substance, effervescent tablets or dispersion tablets or capsules.

These preparations are prepared by known methods such as mixing, dissolving, granulating, drying and tabletting. For example, inclusion complexes of 27% or 50% of the active substance can be filled directly into the appropriate size capsules without any other additives. 363 mg / ml capsules are used. 196 mg of the complex to give a dose of 98 mg of the active ingredient.

The following embodiments are explained, but by no means limited to, the invention:

Example 1.

Dissolve 1600 mg of methyl-beta-cyclodextrin in 20 ml of water. A specially prepared solution of 306.6 mg of clopidogrel base in 2 ml of isopropyl alcohol, 2 ml of water and 93.4 mg of sulfuric acid is then added to this solution. The solution was then stirred for 3 hours at room temperature. It is then filtered, frozen and freeze-dried. 2110 mg of inclusion complex was obtained containing 19% clopidogrel hydrogen sulphate.

Example 2.

Dissolve 1600 mg of beta-cyclodextrin in 30 ml of water and 8 ml of isopropanol at 50 ° C and add a specially prepared solution of 400 mg of clopidogrel hydrogen sulphate in 10 ml of water and 10 ml of isopropanol. The mixture was stirred for 1 hour at 50 ° C, sterile filtered, frozen and lyophilized. A 1920 mg inclusion complex containing 20% clopidogrel hydrogen sulfate is obtained.

Example 3.

g (2-hydroxypropyl) -beta-cyclodextrin is dissolved in 300 ml of water. While stirring, a specially prepared solution of 9.2 g of clopidogrel base and 2.4 ml of hydrochloric acid (37%) in 30 ml of water and 30 ml of isopropanol is added. Stirred for 3 hours at room temperature. The solution is filtered, frozen, and lyophilized. We get it

46.8 g of inclusion complex containing 25.6% clopidogrel hydrochloride. The compound is very easily soluble in water.

Example 4.

g (2-hydroxypropyl) -beta-cyclodextrin is dissolved in 150 ml of water and a specially prepared solution of 6 g of clopidogrel hydrogen sulphate in 20 ml of water and 10 ml of isopropanol is slowly added while stirring. Stir for 2.5 hours at room temperature. Filtered through a fine filter and then dried on a spray dryer in a hot air flow at 120 ° C. An amorphous complex, 22 g, containing 27.2% clopidogrel hydrogen sulphate was obtained.

Example 5.

g of polyvinylpyrrolidone K-30 with a molar mass of 40,000 is dissolved in 120 ml of water. While stirring, a specially prepared solution of 3.83 g of clopidogrel base in 20 ml of isopropanol and 10 ml of water and 1.17 g of sulfuric acid is added. The mixture was stirred at room temperature for 2 hours and then the solvent was evaporated in vacuo. 15 g of an inclusion complex containing 33.3% of clopidogrel hydrogen sulfate are obtained.

Example 6.

Dissolve 1.11 g of clopidogrel base in 20 ml of ethanol, while stirring 0.71 g of 50% sulfuric acid, followed by 2.19 g of methyl beta-cyclodextrin.

The mixture was stirred at 50 ° C for 1 hour and then the solvent was evaporated in vacuo at 50 ° C. The substance was then dried under high vacuum. 3.71 g (100%) of an amorphous white substance are obtained which contains 40% of clopidogrel hydrogen sulphate and melts at 162-165 ° C.

Example 7.

A specially prepared solution of 1 g of clopidogrel hydrogen sulphate in 18 ml of methanol is heated to 50 ° C and 1.5 g (2-hydroxypropyl) -beta-cyclodextrin is added while stirring. Stir for another 1 hour at this temperature.

This solution is then slowly poured into 200 ml of methyl t-butylether during vigorous stirring. The precipitated white solid was filtered and washed with 50 ml of methyl t-butylether. After drying in vacuo, 2.51 g (100%) of an amorphous white substance containing 40% of clopidogrel hydrogen sulfate are obtained. It melts at 166-171 ° C.

Example 8.

Testing the stability of the inclusion complex solution

A solution of the clopidogrel hydrogen sulphate inclusion complex (25%) in (2-hydroxypropyl) -beta cyclodextrin at a concentration of 40 mg of the complex / 40 ml of water was incubated at 50 ± 3 ° C and 85% relate. air humidity.

The reference solution contained 10 mg of clopidogrel hydrogen sulphate / 40 ml of water.

The substance content was monitored by HPLC chromatography under the following conditions:

column:

mobile phase A: mobile phase B: buffer composition:

gradient:

flow rate:

detection:

Orpegen HDSil 18-5S-100, (RP-18), 150 x 4.6 mm,

15% acetonitrile / 85% pH 2.0 buffer,

70% acetonitrile / 30% pH 2.0 buffer,

0.92 g of sodium, heptansulfonate + 1 ml of triethylamine / 1000 ml of water, pH 2.0 was adjusted with 85% perchloric acid, from 100% mob. phase A at 50% A in 20 min, ml / min,

UV at 220 nm.

Test result of (accelerated) stability shown in the decrease in the concentration of the active substance at the time of incubation:

Compound 1 / incubation time (hours) - » 0 1 6 20 34 45 90 clopidogrel hydrogensulfate 99.8 99.1 99,4 99.0 98.9 97.8 96.8 inclusion. complex (25%) 99,9 99,9 99,9 99.5 98.7 98.4 98.0

Solutions of inclusion complexes in water are even slightly more stable during incubation than solutions of clopidogrel hydrogen sulphate of the same concentration.

Claims (12)

Patent claims Clopidogrel inclusion complexes of the formula: and its acid addition salts with polymeric compounds, preferably cyclodextrins. 2. Inclusion complexes of clopidogrel and its addition salts with beta-cyclodextrin. 3. Injection complexes of clopidogrel and its addition salts with methyl-beta-cyclodextrin. 4. Inclusion complexes of clopidogrel and its addition salts with (2-hydroxypropyl) beta-cyclodextrin. 5. Inclusion complexes of clopidogrel and its addition salts with gamma-cyclodextrin. 6. Inclusion complexes of clopidogrel and its addition salts with eta-cyclodextrin. 7. Inclusion complexes of clopidogrel and its addition salts with polyvinylpyrrolidone. Process for the preparation of inclusion complexes of clopidogrel and its addition salts according to claims 1 to 7, characterized in that clopidogrel or its addition salts in aqueous or aqueous / alcoholic solution are mixed only with a solution of cyclodextrin or polyvinylpyrrolidone in a weight ratio of 15 50% clopidogrel relative to the total weight of the complex, stirred for 1 to 4 hours at room temperature or elevated to 60 ° C, filtered and dried. Process according to claim 8, characterized in that the drying is carried out by lyophilization or by dispersing the solution in a stream of hot air at a temperature of from 100 to 150 ° C, or otherwise by removing the solvent, preferably in a vacuum. The process according to claims 8 and 9, characterized in that the drying of the complex is carried out by evaporation of the solvent in vacuo at elevated temperature to 60 ° C. Process according to claims 8 and 9, characterized in that the complex is obtained in solid form by precipitation of the complex solution in one solvent by adding another solvent in which it is insoluble. 12. Pharmaceutical preparations having antithrombotic and antisclerotic action, characterized in that they contain a therapeutically effective amount of the inclusion complex of clopidogrel or its addition salts with beta-cyclodextrin, methyl-beta-cyclo14 dextrin, hydroxyalkyl-beta-cyclodextrins, gamma-cyclodextrins, gamma-cyclodextrins, gamma-cyclodextrins or polyvinylpyrrolidone, together with pharmaceutically acceptable carriers and other excipients.