AMORPHOUS CLOPIDOGREL HYDROGEN SULFATE COMPOSITION
FIELD OF THE INVENTION
The present invention relates to a non-hygroscopic, stable pharmaceutical composition of amorphous clopidogrel hydrogen sulfate.
BACKGROUND OF THE INVENTION
Clopidogrel hydrogen sulfate, (αS)- α-(2-chlorophenyl)-6,7- dihydrothieno[3,2-c]pyridine-5(4H)-acetic acid methyl ester hydrogen sulfate is a platelet aggregation inhibitor.
Clopidogrel hydrogen sulfate is commercially available as a 75 mg tablet (as clopidogrel free base). It is sold under the name PLAVIX. The therapeutic uses of clopidogrel and its salts were disclosed in US
4,529,596 and US 4,847,265.
US 5,989,578 reported pharmaceutical compositions containing pharmaceutically acceptable salts of clopidogrel and aspirin.
US 6,215,005, US 6,180,793, US 5,132,435, US 6,080,875 and WO 02/059128 described various methods of synthesis of clopidogrel and its salts. US 6,429,210 disclosed a crystalline form of clopidogrel hydrogen sulfate designated as form II. The process described in EP 281459 for the preparation of clopidogrel hydrogen sulfate leads to a crystalline form (form I). In the prior art crystalline clopidogrel hydrogen sulfate was used in pharmaceutical compositions.
Clopidogrel hydrogen sulfate in amorphous form has a higher bioavailability than the crystalline forms. Over extended storage periods an amorphous clopidogrel hydrogen sulfate can convert to a crystalline form, with consequent changes in its dissolution profile. So, there is a need for a stable, non-hygroscopic composition comprising amorphous clopidogrel hydrogen sulfate.
Amorphous clopidogrel hydrogen sulfate can be prepared from a crystalline form of clopidogrel hydrogen sulfate or clopidogrel hydrogen sulfate solvate. Thus amorphous clopidogrel hydrogen sulfate may be prepared by dissolving crystalline clopidogrel hydrogen sulfate or clopidogrel hydrogen
sulfate isopropyl alcohol solvate in, for example, methanol, refluxing for about 2 hours and distilling off the solvent s from the solution.
A high dosage strength solid unit oral dosage form of amorphous clopidogrel hydrogen sulfate having satisfactory stability has not been successfully developed prior to the present invention.
The object of the present invention is to provide a stable, non- hygroscopic composition of amorphous clopidogrel hydrogen sulfate.
DESCRIPTION OF THE INVENTION
The present invention provides a non-hygroscopic, stable pharmaceutical formulation of amorphous clopidogrel hydrogen sulfate. More particularly the invention relates to a composition comprising a mixture of amorphous clopidogrel hydrogen sulfate; either or both of calcium stearate and magnesium stearate; and a non-hygroscopic additive. Optionally at least one additional excipient is used. The additional excipients include pharmaceutical lubricants, disintegrators, glidents, adsorbants, fillers, or mixtures thereof. Preferably, the process for preparing a non-hygroscopic, stable oral pharmaceutical formulations of amorphous clopidogrel hydrogen sulfate includes the blending of ingredients including amorphous clopidogrel hydrogen sulfate, calcium stearate or magnesium stearate and a non-hygroscopic additive.
Preferably, the process further includes the step of compressing the ingredients into a solid dosage form after the step of blending. Preferably, amorphous clopidogrel hydrogen sulfate is present in an amount of from about 5% to about 90% of the weight of the final composition, more preferably from about 10% to about 40% and most preferably from about 20% to 30% of the weight of the final composition.
Surprisingly, it has been found that a non-hygroscopic additive in combination with calcium stearate or magnesium stearate prevents the liquefaction of amorphous clopidogrel hydrogen sulfate as a result of moisture uptake and indeed prevents the finished composition from absorbing significant amounts of water over a wide range of relative humidities. The combination of calcium stearate or magnesium stearate and a non-hygroscopic additive is
particularly advantageous since such a combination prevents the liquefaction of amorphous clopidogrel hydrogen sulfate, prevents the conversion of amorphous clopidogrel hydrogen sulfate to a crystalline over an extended period of time and forms a non-hygroscopic and stable mixture which is highly compressible and have optimal flow properties, thereby providing the tablets with excellent physical properties.
Preferably, the pharmaceutical composition is stable under relative humidity of from about 30% to about 75% at 40°C and more preferably from about 30% to about 60% at 25°C. Preferably, the non-hygroscopic additive includes, but is not limited to heavy calcium carbonate, heavy magnesium carbonate, light magnesium oxide, dibasic calcium phosphate anhydrous and calcium silicate.
Preferably, the non-hygroscopic additive is present in an amount of from about 0.5% to about 20% of the weight of the final composition and more preferably from about 2% to 12% of the weight of the final composition.
Preferably, calcium stearate or magnesium stearate is present in an amount of from about 0.1% to about 5% of the weight of the final composition and more preferably from about 0.2% to 2.5% of the weight of the final composition. Calcium stearate and magnesium stearate can also be useful as lubricants.
The additional excipients may be, for example, lubricants, disintegrators, glidents, adsorbents, fillers, or mixtures thereof.
The filler includes, but is not limited to lactose anhydrous, microcrystalline cellulose, mannitol, or mixtures thereof. The lubricant includes, but is not limited to stearic acid, a salt of stearic acid, talc, sodium stearyl fumarate, or mixtures thereof.
Preferably, the disintegrator includes, but is not limited to sodium starch glycolate, starch, magnesium aluminium silicate, or mixtures thereof.
The glidents may be for example colloidal silicon dioxide, talc or mixtures thereof.
Other ingredients such as diluents, stabilizers and antiadherants, conventionally used for pharmaceutical formulations may be included in the present formulation.
The pharmaceutical composition may be, for example, in the form of a tablet, a caplet, a pellet, a capsule, a granule, a pil, a powder or a sachet preferably the pharmaceutical composition is in the form of a tablet. The capsule may contain a powder, a compressed powder or a granule. The pharmaceutical composition of the present invention is administered orally.
The pharmaceutical composition may further be coated with a moisture barrier film, an enteric-coating film or a combination thereof to improve the non- hygroscopic properties of the composition. , , .
The invention is further illustrated by the following non-limiting examples.
Example 1
10,000 tablets of the above formulation were prepared as follows. A blend was prepared of Clopidogrel Hydrogen Sulfate (978.8 g), Microcrystalline Cellulose (350 g), Lactose Anhydrous (2.49 Kg), Hydrogenated Caster Oil (100 g), Heavy Calcium Carbonate (150 g) and Calcium Stearate (30 g) in a blender and mix for 5 to 10 minutes. The final blend was then compressed into 410 mg tablets using 'D' tooling Cadmach compression machine.
Coating solution is prepared by using 102.5 gm of opadry organic with 1.25 L of isopropyl alcohol and 1.25 L of methylene chloride.
10,000 tablets of the above formulation were prepared as follows. A blend was prepared of Clopidogrel Hydrogen Sulfate (978.8 g), Microcrystalline Cellulose (350 g), Lactose Anhydrous (2.29 Kg), Hydrogenated Caster Oil (100 g), Light Magnesium Oxide (150 g) and Calcium Stearate (30 g) in a blender and mix for 5 to 10 minutes. The final blend was then compressed into 390 mg tablets using 'D' tooling Cadmach compression machine.
Coating solution is prepared by using 102.5 gm of opadry organic with 1.25 L of isopropyl alcohol and 1.25 L of methylene chloride.
Example 3
10,000 tablets of the above formulation were prepared as follows. A blend was prepared of Clopidogrel Hydrogen Sulfate (978.8 g), Microcrystalline Cellulose (350 g), Lactose Anhydrous (1.94 Kg), Hydrogenated Caster Oil (100 g), Light Magnesium Carbonate (400 g) and Calcium Stearate (30 g) in a blender and mix for 5 to 10 minutes. The final blend was then compressed into 380 mg tablets using 'D' tooling Cadmach compression machine.
Coating solution is prepared by using 102.5 gm of opadry organic with 1.25 L of isopropyl alcohol and 1.25 L of methylene chloride.
Example 4
10,000 tablets of the above formulation were prepared as follows. A blend was prepared of Clopidogrel Hydrogen Sulfate (978.8 g), Microcrystalline Cellulose (350 g), Mannitol (2.29 Kg), Hydrogenated Caster Oil (100 g), Calcium Silicate
(150 g) and Calcium Stearate (30 g) in a blender and mix for 5 to 10 minutes.
The final blend was then compressed into 390 mg tablets using 'D' tooling
Cadmach compression machine.
Coating solution is prepared by using 102.5 gm of opadry organic with 1.25 L of isopropyl alcohol and 1.25 L of methylene chloride.
Example 5
10,000 tablets of the above formulation were prepared as follows. A blend was prepared of Clopidogrel Hydrogen Sulfate (978.8 g), Microcrystalline Cellulose (350 g), Mannitol (2.04 Kg), Hydrogenated Caster Oil (100 g), Heavy Calcium carbonate (200 g) and Calcium Stearate (30 g) in a blender and mix for 5 to 10 minutes. The final blend was then compressed into 370 mg tablets using 'D' tooling Cadmach compression machine.
Coating solution is prepared by using 102.5 gm of opadry organic with 1.25 L of isopropyl alcohol and 1.25 L of methylene chloride.
Example 6
10,000 tablets of the above formulation were prepared as follows. A blend was prepared of Clopidogrel Hydrogen Sulfate (978.8 g), Microcrystalline Cellulose (350 g), Mannitol (Pearlitol SD-200) (1.94 Kg), Hydrogenated Caster Oil (100 g), Light Magnesium Carbonate (400 g) and Calcium Stearate (30 g) in a blender and mix for 5 to 10 minutes. The final blend was then compressed into 380 mg Otablets using 'D' tooling Cadmach compression machine. Coating solution is prepared by using 102.5 gm of opadry organic with 1.25 L of isopropyl alcohol and 1.25 L of methylene chloride.
Example 7
10,000 tablets of the above formulation were prepared as follows. A blend was prepared of Clopidogrel Hydrogen Sulfate (978.8 g), Microcrystalline Cellulose (350 g), Lactose Anhydrous (2.49 Kg), Hydrogenated Caster Oil (100 g), Calcium silicate (150 g) and Calcium Stearate (30 g) in a blender and mix for 5 to 10 minutes. The final blend was then compressed into 410 mg tablets using 'D' tooling Cadmach compression machine.
Coating solution is prepared by using 102.5 gm of opadry organic with 1.25 L of isopropyl alcohol and 1.25 L of methylene chloride.