WO2000001364A1

WO2000001364A1 - Stable pharmaceutical compositions of thieno [3,2-c] pyridine derivatives

Info

Publication number: WO2000001364A1
Application number: PCT/IN1999/000015
Authority: WO
Inventors: Pratibha Pilgaonkar; Bhanumathi Balasubramaniam; Mohit Gupta; Satish Chandra Upadhyay
Original assignee: Sun Pharmaceutical Industries Ltd.
Priority date: 1998-07-01
Filing date: 1999-04-29
Publication date: 2000-01-13
Also published as: AU4288599A

Abstract

A stable pharmaceutical composition of thieno [3,2-c] pyridine derivatives includes a water-soluble hydrophilic lubricant, namely polyethylene glycol, and at least one pharmaceutically acceptable excipient. A preferred thieno [3,2-c] pyridine derivative is ticlopidine or ticlopidine hydrochloride, which is useful for its anti-inflammatory, vasodilator and blood platelet aggregation inhibitor action. The pharmaceutical composition is free or substantially free of magnesium stearate, a water soluble polyvinlypyrrolidone and sodium starch glycollate.

Description

STABLE PHARMACEUTICAL COMPOSITIONS OF THIENO [3,2-C] PYRIDINE DERIVATIVES

FIELD OF THE INVENTION

The present invention relates to stable pharmaceutical compositions of thieno [3,2-c] pyridine derivatives.

BACKGROUND ART

United States Patent No. 4,051, 141 disclosed and claimed thieno [3,2-c] pyridine derivatives having the formula:

wherein R is selected from the group consisting of phenyl, phenyl substituted with 1 or 2 halogen atoms or alkyl having 1-6 carbon atoms or alkoxy having 1-6 carbon atoms or hydroxy or nitro, benzoyl and benzoyl substituted with chloro or fluoro or alkyl having 1-6 carbon atoms or alkoxy having 1-6 carbon atoms or 1 or 2 hydroxy groups or nitro; Ri is selected from the group consisting of hydrogen, halogen, hydroxy and alkyl having 1-6 carbon atoms; R2 is selected from hydrogen and halogen and n is 1 or 2, and in which the symbol Ri may have different meanings in each radical - (CHRi)- when n is 2, and the pharmaceutically acceptable acid addition salts thereof. The thieno [3,2-c] pyridine derivatives were disclosed as being useful for their anti-inflammatory, vasodilator and blood platelet aggregation inhibitor action. An example of the thieno [3,2-c] pyridine derivative is ticlopidine or its pharmaceutically acceptable acid addition salt.

United States Patents Nos. 4,490,377 and 4,591,592 both relate to stable pharmaceutical compositions comprising a thieno-pyridine derivative, a pharmaceutically acceptable non- volatile acidic compound, and at least one pharmaceutically acceptable excipient. These patents assert that the presence of the non-volatile acidic compound in the formulation prevents the discoloration of the tablet. The discoloration was attributed to degradation of ticlopidine for which the presence of certain excipients such as gelatin, polyvinylpyrrolidone, and magnesium stearate was believed to be an initiating factor.

United States Patent No. 5,520,928 discloses a pharmaceutical composition, which comprises ticlopidine hydrochloride, a lubricant and stabilizer, and pharmaceutically acceptable excipients, wherein a single substance, namely stearic acid, serves as both lubricant and stabilizer. This patent states that a stable ticlopidine hydrochloride composition is provided in the absence of any organic acid other than stearic acid.

In formulation of pharmaceutical dosage forms, the drug is mixed with pharmaceutically acceptable excipients. The pharmaceutically acceptable excipients themselves or trace impurities present in them may interact with the drug or accelerate the rate at which the drug degrades. In pharmaceuticals, it is essential that the drug in the composition be chemically stable in order to provide formulations to the patients that are safe and effective. It is known from the prior art that thieno [3,2-c] pyridine derivatives are unstable and degrade in the presence of pharmaceutically acceptable excipients, for example, gelatin, polyvinylpyrrolidone and magnesium stearate. We have also found that they degrade in the presence of sodium starch glycollate. In the above- mentioned prior art compositions, magnesium stearate or stearic acid was used as lubricant.

It is well known to those skilled in the art that both magnesium stearate and stearic acid are water insoluble hydrophobic compounds.

These lubricants thus must be used in appropriate amounts in a careful and reproducible manner in each manufacturing batch such that they do not hinder the dissolution and thereby the bioavailability of the drugs. Although any deviation from the prescribed manner entails bioavailability risks, magnesium stearate is still widely used in tablet formulations because of its desirable lubricant attributes. However, the use of magnesium stearate in thieno [3,2-c] pyridine derivative compositions is particularly undesirable because it is found to increase the rate of degradation of thieno [3,2-c] pyridine derivatives.

SUMMARY OF THE INVENTION

The present invention provides a pharmaceutical composition of thieno [3,2-c] pyridine derivatives comprising a thieno [3,2-c] pyridine derivative, a water-soluble hydrophilic lubricant and pharmaceutically acceptable excipient(s) such that the pharmaceutical composition:

(a) is stable,

(b) is easy to process into tablets or capsules, and (c) maintains its disintegration and dissolution characteristics upon storage.

Usually, a hydrophilic environment such as around a hydrophilic lubricant that has a tendency to take up moisture from the environment increases the rate of drug degradation. However, it was surprisingly found that polyethylene glycol inspite of its hydrophilic nature provides an environment in which thieno [3,2-c] pyridine derivatives exhibit a high degree of chemical stability. More specifically, it was surprisingly found that the HPLC chromatogram obtained from the HPLC stability indicating assay method showed only a peak for ticlopidine and did not show any other peak such as that for compounds known to result from the degradation of ticlopidine, even after the composition had been stored at 60 °C for 1 month or at 40°C/75% Relative Humidity for 1 month.

It is well known to those skilled in the art that polyethylene glycol may become soft and sticky due to heat generated in processing. We further believe that they act as good solvents for the thieno [3,2-c] pyridine derivatives and thereby result in gradual changes in tablet properties such as tablet hardness, disintegration and dissolution. However, preferred pharmaceutical compositions of the present invention are not only surprisingly stable but are also easy to process into tablets or capsules and maintain their disintegration and dissolution characteristics upon storage.

It is to be understood that both the foregoing general description and the following detailed description are exemplary, but are not restrictive, of the invention.

DETAILED DESCRIPTION OF THE INVENTION

The present invention provides a stable oral pharmaceutical composition which is free of or substantially free of magnesium stearate, a water-soluble polyvinylpyrrolidone and sodium starch glycollate; and comprises:

(a) therapeutically effective amounts of thieno [3,2-c] pyridine derivative having the formula:

wherein R is selected from the group consisting of (i) phenyl, (ii) phenyl substituted with 1 or 2 halogen atoms or alkyl having 1-6 carbon atoms or alkoxy having 1-6 carbon atoms or hydroxy or nitro, (iii) benzoyl and (iv) benzoyl substituted with chloro or fluoro or alkyl having 1-6 carbon atoms or alkoxy having 1-6 carbon atoms or 1 or 2 hydroxy groups or nitro; Ri is selected from the group consisting of hydrogen, halogen, hydroxy and alkyl having 1-6 carbon atoms; R2 is selected from hydrogen and halogen and n is 1 or 2, and in which the symbol Ri may have different meanings in each radical -(CHRi)- when n is 2, or a pharmaceutically acceptable acid addition salt thereof; (b) a water-soluble hydrophilic lubricant comprising a polyethylene glycol having an average molecular weight from about 1000 Dalton to about 30,000 Dalton; and

(c) at least one pharmaceutically acceptable excipient. According to the present invention, the pharmaceutical composition contains a thieno [3,2-c] pyridine derivative or its pharmaceutically acceptable acid addition salt. The thieno [3,2-c] pyridine derivative may be used in therapeutically effective amounts useful for their anti-inflammatory, vasodilator and blood platelet aggregation inhibitor action. More particularly, the preferred class of compounds to which this invention is applicable includes compounds of the formula shown above in which R is phenyl or phenyl substituted with one or two halogen atoms, Ri is hydrogen, R₂ is hydrogen and n is 1, or a pharmaceutically acceptable acid addition salt thereof. In a preferred embodiment of the present invention, the thieno [3,2-c] pyridine derivative is ticlopidine or its pharmaceutically acceptable acid addition salt.

According to the present invention, the pharmaceutical composition contains a water-soluble hydrophilic lubricant which is polyethylene glycol. Polyethylene glycol is a condensation polymer formed by the reaction of ethylene oxide and water under pressure in the presence of a catalyst. The polyethylene glycol may have a general formula HOCH2(CH2θCH2)mCH_OH where m represents the average number of oxyethylene groups. Alternatively, it may be represented by the general formula H(OCH₂CH₂)nOH, where n is a number 1 more than the value of m in the previous formula. Polyethylene glycol is commonly referred to by its abbreviated synonym PEG. Polyethylene glycol is available in different grades based on its molecular weight. The number, which follows PEG, indicates the average molecular weight of the polymer. The polyethylene glycol grades 200-600 are liquids while grades 1000 and above such as PEG 1500, PEG 4000, PEG 6000, PEG 8000 and PEG 20,000 are solid at ambient temperature. Polyethylene glycol is sold under the trademarks Carbowax^® and Lutrol E^® by Union Carbide Corporation and BASF Pic, respectively.

Any pharmaceutically acceptable grade of polyethylene glycol is believed to provide a stable microenvironment for the thienopyridine derivative. The polyethylene glycol that may be used in the present invention is a solid at ambient temperature and has an average molecular weight from about 1000 Dalton to about 30,000 Dalton. In a preferred embodiment of the present invention, the polyethylene glycol has an average molecular weight of about 6000 Dalton to about 20,000 Dalton. More specifically, grades of PEG 6000 and above, which are available as free flowing milled powders, are preferred. These grades have a higher melting point and therefore have a reduced tendency (as opposed to lower molecular weight PEG) for causing stickiness between dies and punches when the material becomes warm during compression. These grades can also improve the binder effectiveness and impart plasticity to the formulation.

According to the present invention, the polyethylene glycol may be used in amounts effective as a lubricant.

The preferable amount of polyethylene glycol is from about 0.1 % to about 10%, more preferably from about 0.5% to about 5%, by weight of the total weight of the composition.

According to the present invention, the pharmaceutical composition contains at least one pharmaceutically acceptable excipient (i.e., other than polyethylene glycol). The pharmaceutical excipients that may be used in the present invention include tabletmg excipients that are well known to those skilled in the art. These include diluents, disintegrants, binders, lubricants, coloring agents, flavoring agents, and sweetening agents. Examples of pharmaceutically acceptable excipients may be found in the Handbook of Pharmaceutical Excipients, Second Edition, 1994 and other sources of pharmaceutical literature.

In the preferred embodiment of the present invention, the pharmaceutically acceptable excipient is microcrystalline cellulose. Microcrystalline cellulose is a purified, partially depolymerized cellulose derived from purified grades of wood pulp. It is sold under the trademarks Avicel^® by FMC Corporation, USA and Emcocel^® by Edward Mendall Co Inc, USA. Microcrystalline cellulose is commercially available in different particle size grades such as Avicel PH -101, Avicel PH-102, Avicel PH- 103, Avicel PH-105, Avicel PH-112, Avicel PH-113, Avicel PH-200, Avicel PH-301 and Avicel PH-302. The different grades have different properties and applications and function as directly compressible diluents or filler-binders.

Furthermore, microcrystalline cellulose also functions as a good disintegrant by allowing water to enter the tablet matrix by means of capillary pores. A pharmaceutical excipient such as microcrystalline cellulose also acts as a good adsorbent for the polyethylene glycol such that during the process of compressing the pharmaceutical composition into tablets it contributes to resolving the problem of sticking of the tablet surfaces to the punch faces and the die walls. It was found that pharmaceutical compositions of the present invention were easy to process into tablets when microcrystalline cellulose was used as a diluent. The preferred grade that is used in the present invention is Avicel^® PH-102.

The microcrystalline cellulose may be used in the present invention in an amount from about 1 % to about 85 % by weight of the total weight of the composition. In preferred embodiments, the microcrystalline cellulose is used in an amount from about 5% to about 40% (and most preferably from about 10% to about 25%) by weight of the total weight of the composition.

In preferred embodiments of the present invention, talc is used as a lubricant in combination with the polyethylene glycol. Talc is preferably used in the present invention because it has an antiadherent action and contributes to resolving the problem of sticking of the tablet surfaces to the punch faces and the die walls. The talc may be used in an amount from about 2% to about 10% by the weight of the total weight of the composition. In more preferred embodiments of the present invention, the talc is used in amounts from about 5% to about 10% by weight of the total weight of the composition.

The pharmaceutical composition of the present invention may be formed into tablets by conventional wet granulation, dry granulation or direct compression methods.

In one embodiment of the wet granulation procedure, generally the drug, the diluent(s) (e.g. lactose) and a part of the disintegrant(s) (e.g. starch) are mixed together. The excipients in this dry mixture may themselves act as binders in which case the dry mixture may be granulated using a suitable solvent preferably purified water. Alternatively the dry mixture may be granulated with the aid of a solution of a binder (e.g. methylcellulose). Solutions of binders may be prepared in any of the organic solvents or in water or in blends of water and organic solvents that are well known to those skilled in the art. Preferably, the solvent may be water or a mixture of water and alcohol. The granules are dried and then mixed with the lubricant(s) and the remaining disintegrant(s). The lubricated granules are compressed into tablets.

In another embodiment of the wet granulation procedure the drug and a part of the disintegrant(s) are mixed together and granulated as decribed above. The granules are dried and then mixed with the lubricant(s), diluent(s) and the remaining disintegrant(s). The lubricated granules are compressed into tablets.

In the dry granulation procedure, the drug, the diluent(s), the binder(s) and a part of the disintegrant(s) are mixed and compacted, and the compacted mass is passed through sieves to form granules. The granules are mixed with the lubricant(s) and the remaining disintegrant(s) and then compressed into the tablets.

In direct compression the drug is mixed with polyethylene glycol and the pharmaceutically acceptable excipient(s), and the blend so obtained is compressed into tablets.

The tablets formed according to the process of the present invention may optionally be coated by conventional methods using a dispersion of a water-soluble polymer. The pharmaceutical composition of the present invention may be formed into capsules in any suitable manner. For example, the ingredients may be mixed and the blend so obtained filled into capsules. Alternatively, the blend may be granulated by conventional means and the granules so obtained filled into capsules. Yet another way is to convert the blend into spherical pellets by conventional means and fill the pellets so obtained into capsules. Still another way is by making tablets as herein described and filling the tablets into capsules. The invention is further illustrated by the following examples. These examples are by no means intended to limit the scope of the invention but are given by way of illustration.

EXAMPLE 1

It was found that a 1 : 1 physical mixture of ticlopidine with magnesium stearate or sodium starch glycollate or polyvinylpyrrolidone (PVP K-30) was discolored upon storage at 85 °C for 24 hours. A stability indicating HPLC assay method was used to analyze the mixtures. The HPLC chromatogram showed peaks for the degradation products of ticlopidine. These excipients were not used in the pharmaceutical composition.

Tablets were made according to the formula given in Table 1

TABLE 1

This formulation is prepared by a conventional wet granulation method in which ticlopidine hydrochloride and a part of pregelatinized starch are mixed together in a blender and granulated with water. The dried granules are sized and mixed with sifted microcrystalline cellulose, talc and polyethylene glycol 8000 and rest of the pregelatinized starch. The resultant blend is compressed into core tablets which are dedusted and coated using a hydroxypropylmethylcellulose based aqueous coating system commercially available under the Trademark Opadry Yellow YS 12524 A^® to a weight build-up of 4% .

The coated tablets were placed in high density polyethylene (HDPE) bottle having a child resistant cap and stored at 40°C and 75% Relative Humidity (RH).

The tablets were analyzed for any change in dissolution according to standard procedure as described under " Dissolution: Procedure for Capsules, Uncoated Tablets and Plain Coated Tablets" in United States Pharmacopoeia, XXIII, page 1792 (Published by the United States Pharmacopoeial Convention, Inc, 12601 Twinbrook Parkway, Rockville, MD). The dissolution medium was 900 ml degassed 0.1N HC1. (Type I Apparatus, basket speed 50 rpm). The drug content was determined by a stability indicating HPLC method. The results are indicated in Table 2. The "Assay" in the table represents calculated percentage over theoretical drug content in the tablet i.e. 250.0 mg ticlopidine hydrochloride. The results demonstrate that the formulation was stable.

TABLE 2

EXAMPLE 2 Tablets were made according to the formula given in Table 3. TABLE 3

The ticlopidine hydrochloride, microcrystalline cellulose, the pregelatinized starch and corn starch were mixed together in a suitable blender . A wet mass was formed by mixing purified water and the wet mass passed through sieves. The granules obtained were dried, milled and sized and then blended with PEG 8000 and talc. The lubricated granules were compressed into tablets. The tablets were coated using a hydroxypropylmethylcellulose based aqueous coating system commercially available under the trademark Opadry Y- 1-7000^® to a weight build-up of 2% . The coated tablets were placed in high density polyethylene (HDPE) bottles, having a child-resistant cap and stored at 40°C/75% RH.

The tablets were tested for any change in disintegration as per standard procedure described under disintegration test procedure for Plain Coated Tablets in the United States Pharmacopoeia, XXIII, page 1791 (Published by the United States Pharmacopoeial Convention, Inc, 12601 Twinbrook Parkway, Rockville, MD). The tablets were tested for dissolution as described in Example 1 . The drug content was determined by stability indicating HPLC method. The results are indicated in Table 4.

TABLE 4

The HPLC chromatograms showed a peak for ticlopidine but did not show any other peak such as those that were detected in mixtures of ticlopidine with magnesium stearate or sodium starch glycollate or with polyvinylpyrrolidone (PVP K-30).

EXAMPLE 3 Tablets were made according to the formula given in Table 5. TABLE 5

The ticlopidine hydrochloride, lactose monohydrate, the pregelatinized starch and part of the com starch (39.0 mg) were mixed together in a suitable blender. A wet mass was formed by mixing purified water and the wet mass was passed through sieves. The granules obtained were dried, milled, sized, and then blended with remaining starch (19.5 mg), PEG 8000 and the talc. The lubricated granules were compressed into tablets.

The tablets were coated using a hydroxypropylmethylcellulose based aqueous coating system commercially available under the trademark Opadry Y- 1-7000^® to a weight build-up of 2% .

The coated tablets were placed in high-density polyethylene (HDPE) bottles having a child-resistant cap and stored at 60°C. The drug content was deteπnined by a stability indicating HPLC method. The results are indicated in Table 6. Table 6

Initial 15 days 1 month 60°C 60°C

Assay 101.67% 102.07% 101.85%

The HPLC chromatograms showed a peak for ticlopidine but did not show any other peak such as those that were detected in mixtures of ticlopidine with magnesium stearate or sodium starch glycollate or polyvinylpyrrolidone. The data demonstrate that the tablets were stable.

Although illustrated and described herein with reference to certain specific embodiments and examples, the present invention is nevertheless not intended to be limited to the details shown. Rather, various modifications may be made in the details within the scope and range of equivalents of the claims and without departing from the spirit of the invention.

Claims

1. A stable oral pharmaceutical composition which is free or substantially free of magnesium stearate, a water-soluble polyvinylpyrrolidone and sodium starch glycollate; and comprises:

wherein R is selected from the group consisting of (i) phenyl, (ii) phenyl substituted with 1 or 2 halogen atoms or alkyl having 1-6 carbon atoms or alkoxy having 1-6 carbon atoms or hydroxy or nitro, (iii) benzoyl and (iv) benzoyl substituted with chloro or fluoro or alkyl having 1-6 carbon atoms or alkoxy having 1-6 carbon atoms or 1 or 2 hydroxy groups or nitro; Ri is selected from the group consisting of hydrogen, halogen, hydroxy and alkyl having 1-6 carbon atoms; R2 is selected from hydrogen and halogen and n is 1 or 2, and in which the symbols Ri may have different meanings in each radical - (CHRi)- when n is 2, or a pharmaceutically acceptable acid addition salt thereof;

(b) a water-soluble hydrophilic lubricant comprising a polyethylene glycol having an average molecular weight from about 1000 Dalton to about 30,000 Dalton; and

(c) at least one pharmaceutically acceptable excipient.

. A stable oral pharmaceutical composition as in claim 1 wherein the thieno [3,2-c] pyridine derivative has the formula

wherein R is phenyl or phenyl substituted with one or two halogen atoms, Ri is hydrogen, R₂ is hydrogen and n is 1, or a pharmaceutically acceptable acid addition salt thereof.

3. A stable oral pharmaceutical composition as in claim 1 wherein the thieno [3,2-c] pyridine derivative is ticlopidine or a pharmaceutically acceptable acid addition salt thereof.

4. A stable oral pharmaceutical composition as in claim 1 wherein the polyethylene glycol has an average molecular weight from about 6000 Dalton to about 20,000 Dalton.

5. A stable oral pharmaceutical composition as in claim 1 wherein the polyethylene glycol is present in amounts effective as a lubricant.

6. A stable oral pharmaceutical composition as in claim 1 wherein the polyethylene glycol is present in amounts from about 0.5% to about 5 % by weight of the total weight of the pharmaceutical composition. 7. A stable oral pharmaceutical composition as in claim 1 wherein the pharmaceutically acceptable excipient comprises microcrystalline cellulose.

8. A stable oral pharmaceutical composition as in claim 7 wherein the microcrystalline cellulose is present in amounts from about 1 % to about 85% by weight of the total weight of the composition. 9. A stable oral pharmaceutical composition as in claim 7 wherein the microcrystalline cellulose is present in amounts from about 10% to about 25 % by weight of the total weight of the composition.

10. A stable oral pharmaceutical composition as in claim 1 wherein talc is used as a lubricant in combination with the polyethylene glycol.

11. A stable oral pharmaceutical composition as in claim 10 wherein the talc is present in an amount from about 2% to about 10% by weight of the total weight of the composition. 12. A stable oral pharmaceutical composition which is free or substantially free of magnesium stearate, a water-soluble polyvinylpyrrolidone and sodium starch glycollate; and comprises:

Ticlopidine hydrochloride in a therapeutically effective amounts;

Microcrystalline cellulose from about 5% to about 40 % by weight of the total weight of the composition;

A water-soluble hydrophilic lubricant comprising a polyethylene glycol from about 0.1 % to about 10% by weight of the total weight of the composition; said polyethylene glycol having an average molecular weight from about 1000 Dalton to about 30,000 Dalton; and

Talc from about 2% to about 10% by weight of the total weight of the composition.

3. A stable oral pharmaceutical composition which is free or substantially free of magnesium stearate, a water-soluble polyvinylpyrrolidone and sodium starch glycollate; and comprises: Ticlopidine hydrochloride in a therapeutically effective amounts;

Microcrystalline cellulose from about 10% to about 25 % by weight of the total weight of the composition;

A water-soluble hydrophilic lubricant comprising a polyethylene glycol from about 0.5% to about 5% by weight of the total weight of the composition; said polyethylene glycol having an average molecular weight from about 1000 Dalton to about 30,000 Dalton; and Talc from about 5% to about 10% by weight of the total weight of the composition.

14. A stable oral pharmaceutical composition which is free or substantially free of magnesium stearate, a water-soluble polyvinylpyrrolidone and sodium starch glycollate; and comprises:

Ticlopidine hydrochloride from about 50% to about 70% by weight of the total weight of the composition;

Microcrystalline cellulose from about 15% to about 25 % by weight of the total weight of the composition; Starch from about 5% to about 15% by weight of the total weight of the composition;

PEG 8000 from about 0.5% to about 75% by weight of the total weight of the composition; and

Talc from about 5% to about 10% by weight of the total weight of the composition.