Claims for Patent: 6,495,162

Summary for Patent: 6,495,162

Title:	Controlled release oral tablet having a unitary core
Abstract:	A controlled release antihyperglycemic tablet that does not contain an expanding polymer and comprising a core containing the antihyperglycemic drug, a semipermeable membrane coating the core and at least one passageway in the membrane.
Inventor(s):	Cheng; Xiu Xiu (Davie, FL), Chen; Chih-Ming (Davie, FL), Jan; Steve (Coral Springs, FL), Chou; Joseph (Coral Springs, FL)
Assignee:	Andrx Pharmaceuticals, Inc. (Davie, FL)
Application Number:	10/016,556
Patent Claims:	1. A controlled release pharmaceutical tablet comprising: (a) a core comprising: (i) 50-98% of an antihyperglycemic drug; (ii) 0-40% of a binding agent; and (iii) 0-20% of an absorption enhancer; (b) a water soluble seal coat; (c) a semipermeable membrane coating covering said core wherein the membrane is permeable to the passage of water and biological fluids and is impermeable to the passage of the antihyperglycemic drug wherein said coating comprises 50-99% of a polymer; 0-40% of a flux enhancer and 0-25% of a plasticizer; and (d) at least one passageway in the semipermeable membrane for the release of the antihyperglycemic drug. 2. A controlled release pharmaceutical tablet as defined in claim 1 wherein the core consists essentially of: 75-95% of the antihyperglycemic drug; 3-15% of the binding agent; and 2-10% of the absorption enhancer; and the coating comprises: 75-95% of the polymer; 2-20% of the flux enhancer; and 2-15% of the plasticizer. 3. A controlled release pharmaceutical tablet as defined in claim 1 that exhibits the following dissolution profile when tested in a USP type 2 apparatus at 75 rpm in 900 ml of simulated intestinal fluid (pH 7.5 phosphate buffer) and at 37.degree. C.: after 2 hours 0-25% of the drug is released; after 4 hours 10-45% of the drug is released; after 8 hours 30-90% of the drug is released; after 12 hours not less than 50% of the drug is released; after 16 hours not less than 60% of the drug is released; and after 20 hours not less than 70% of the drug is released. 4. A controlled release pharmaceutical tablet as defined in claim 1 that exhibits the following dissolution profile when tested in a USP type 2 apparatus at 75 rpm in 900 ml of simulated intestinal fluid (pH 7.5 phosphate buffer) and at 37.degree. C.: after 2 hours 0-15% of the drug is released; after 4 hours 20-40% of the drug is released; after 8 hours 45-90% of the drug is released; after 12 hours not less than 60% of the drug is released; after 16 hours not less than 70% of the drug is released; and after 20 hours not less than 80% of the drug is released. 5. A controlled release pharmaceutical tablet as defined in claim 1 that is administered with or shortly after the evening meal. 6. A controlled release pharmaceutical tablet as defined in claim 1 wherein the binding agent is water soluble. 7. A controlled release pharmaceutical tablet as defined in claim 1 wherein the water soluble binding agent is polyvinyl pyrrolidone, hydroxypropyl cellulose, hydroxyethyl cellulose, waxes or mixtures thereof. 8. A controlled release pharmaceutical tablet as defined in claim 7 wherein the water soluble binding agent is polyvinyl pyrrolidone. 9. A controlled release pharmaceutical tablet as defined in claim 1 wherein the absorption enhancer is selected from the group consisting of fatty acids, surfactants, chelating agents, bile salts or mixtures thereof. 10. A controlled release pharmaceutical tablet as defined in claim 1 wherein the absorption enhancer is a fatty acid selected from the group consisting of capric acid, oleic acid or their monoglycerides. 11. A controlled release pharmaceutical tablet as defined in claim 1 wherein the absorption enhancer is a surfactant selected from the group consisting of sodium lauryl sulfate, sodium taurocholate and polysorbate 80. 12. A controlled release pharmaceutical tablet as defined in claim 1 wherein the absorption enhancer is a chelating agent selected from the group consisting of citric acid, phytic acid, ethylene diamine tetraacetic acid and ethylene glycol-bis(.beta.-aminoethyl ether)-N,N,N,N-tetraacetic acid. 13. A controlled release pharmaceutical tablet as defined in claim 1 wherein the absorption enhancer is a bile salt. 14. A controlled release pharmaceutical tablet as defined in claim 1 wherein the absorption enhancer is sodium lauryl sulfate. 15. A controlled release pharmaceutical tablet as defined in claim 1 wherein the semipermeable membrane around the core is a water insoluble cellulose derivative. 16. A controlled release pharmaceutical tablet as defined in claim 15 wherein the water insoluble cellulose derivative in the membrane around the core is cellulose acetate. 17. A controlled release pharmaceutical tablet as defined in claim 1 wherein semipermeable membrane comprises a flux enhancer. 18. A controlled release pharmaceutical tablet as defined in claim 17 wherein the flux enhancer is sodium chloride, potassium chloride, sucrose, sorbitol, mannitol, polyethylene glycol, propylene glycol, hydroxypropyl cellulose, hydroxypropyl methycellulose, hydroxypropyl methycellulose phthalate, cellulose acetate phthalate, polyvinyl alcohols, methacrylic acid copolymers or mixtures thereof. 19. A controlled release pharmaceutical tablet as defined in claim 18 wherein the flux enhancer is polyethylene glycol with an average molecular weight between 380 and 420. 20. A controlled release pharmaceutical tablet as defined in claim 1 wherein the plasticizer is triacetin. 21. A controlled release pharmaceutical tablet as defined in claim 1 wherein at least two passageways are formed in the semipermeable membrane. 22. A controlled release pharmaceutical tablet as defined in claim 1 wherein peak plasma levels are obtained 8-12 hours after administration. 23. A controlled release tablet as defined in claim 1 wherein the antihyperglycemic drug is a biguanide. 24. A controlled release tablet as defined in claim 1 wherein the antihyperglycemic drug is metformin or a pharmaceutically acceptable salt thereof. 25. A controlled release antihyperglycemic tablet comprising: (a) a core consisting essentially of: (i) 50-98% of metformin or a pharmaceutically acceptable salt thereof; (ii) 0-40% of a water soluble binding agent; and (iii) 0-20% of an absorption enhancer; (b) optionally a water soluble seal coat; (c) a semipermeable membrane coating covering said core comprising: (i) 50-99% of a polymer; (ii) 0-40% of a flux enhancer; and (iii) 0-25% of a plasticizer; and (d) at least one passageway in the semipermeable membrane for the release of metformin. 26. A controlled release pharmaceutical tablet as defined in claim 25 wherein the core consists essentially of: 75-95% of the metformin of a pharmaceutically acceptable salt thereof; 3-15% of the binding agent; and 2-10% of the absorption enhancer; and the coating comprises: 75-95% of the polymer; 2-20% of the flux enhancer; and 2-15% of the plasticizer; and at least one passageway in the semipermeable membrane for the release of metformin. 27. A controlled release pharmaceutical tablet as defined in claim 25 that exhibits the following dissolution profile when tested in a USP type 2 apparatus at 75 rpm in 900 ml of simulated intestinal fluid (pH 7.5 phosphate buffer) and at 37.degree. C.: after 2 hours 0-25% of the drug is released; after 4 hours 10-45% of the drug is released; after 8 hours 30-90% of the drug is released; after 12 hours not less than 50% of the drug is released; after 16 hours not less than 60% of the drug is released; and after 20 hours not less than 70% of the drug is released. 28. A controlled release pharmaceutical tablet as defined in claim 25 that exhibits the following dissolution profile when tested in a USP type 2 apparatus at 75 rpm in 900 ml of simulated intestinal fluid (pH 7.5 phosphate buffer) and at 37.degree. C.: after 2 hours 0-15% of the drug is released; after 4 hours 20-40% of the drug is released; after 8 hours 45-90% of the drug is released; after 12 hours not less than 60% of the drug is released; after 16 hours not less than 70% of the drug is released; and after 20 hours not less than 80% of the drug is released. 29. A controlled release pharmaceutical tablet as defined in claim 25 that is administered with or shortly after the evening meal. 30. A controlled release pharmaceutical tablet as defined in claim 25 wherein the water soluble binding agent is polyvinyl pyrrolidone, hydroxypropyl cellulose, hydroxyethyl cellulose, waxes or mixtures thereof. 31. A controlled release pharmaceutical tablet as defined in claim 30 wherein the water soluble binding agent is polyvinyl pyrrolidone. 32. A controlled release pharmaceutical tablet as defined in claim 25 wherein the absorption enhancer is selected from the group consisting of fatty acids, surfactants, chelating agents, bile salts or mixtures thereof. 33. A controlled release pharmaceutical tablet as defined in claim 25 wherein the absorption enhancer is a fatty acid selected from the group consisting of capric acid, oleic acid or their monoglycerides. 34. A controlled release pharmaceutical tablet as defined in claim 25 wherein the absorption enhancer is a surfactant selected from the group consisting of sodium lauryl sulfate, sodium taurocholate and polysorbate 80. 35. A controlled release pharmaceutical tablet as defined in claim 25 wherein the absorption enhancer is a chelating agent selected from the group consisting of citric acid, phytic acid, ethylene diamine tetraacetic acid and ethylene glycol-bis(.beta.-aminoethyl ether)-N,N,N,N-tetraacetic acid. 36. A controlled release pharmaceutical tablet as defined in claim 25 wherein the absorption enhancer is a bile salt. 37. A controlled release pharmaceutical tablet as defined in claim 25 wherein the absorption enhancer is sodium lauryl sulfate. 38. A controlled release pharmaceutical tablet as defined in claim 25 wherein the semipermeable membrane around the core is a water insoluble cellulose derivative. 39. A controlled release pharmaceutical tablet as defined in claim 25 wherein the water insoluble cellulose derivative in the membrane around the core is cellulose acetate. 40. A controlled release pharmaceutical tablet as defined in claim 25 wherein semipermeable membrane comprises a flux enhancer. 41. A controlled release pharmaceutical tablet as defined in claim 40 wherein the flux enhancer is sodium chloride, potassium chloride, sucrose, sorbitol, mannitol, polyethylene glycol, propylene glycol, hydroxypropyl cellulose, hydroxypropyl methycellulose, hydroxypropyl methycellulose phthalate, cellulose acetate phthalate, polyvinyl alcohols, methacrylic acid copolymers or mixtures thereof. 42. A controlled release pharmaceutical tablet as defined in claim 41 wherein the flux enhancer is polyethylene glycol with an average molecular weight between 380 and 420. 43. A controlled release pharmaceutical tablet as defined in claim 25 wherein the plasticizer is triacetin. 44. A controlled release pharmaceutical tablet as defined in claim 25 wherein at least two passageways are formed in the semipermeable membrane. 45. A controlled release pharmaceutical tablet as defined in claim 25 wherein peak plasma levels are obtained 8-12 hours after administration. 46. A controlled release pharmaceutical tablet as defined in claim 25 further comprising an effective amount of the metformin or pharmaceutically acceptable salt coated onto the semipermeable membrane or mixed into the semipermeable membrane to provide an immediate release of an effective amount of the metformin or pharmaceutically acceptable salt. 47. A controlled release tablet consisting of: (a) a core consisting essentially of: (i) 50-98% of metformin or a pharmaceutically acceptable salt thereof; (ii) 0-40% of a water soluble binding agent; and (iii) 0-20% of an absorption enhancer; (b) optionally a water soluble seal coat; (c) a semipermeable membrane coating covering said core consisting essentially of: (i) 50-99% of a polymer; (ii) 0-40% of a flux enhancer; and (iii) 0-25% of a plasticizer; and (e) at least one passageway in the semipermeable membrane for the release of metformin.