Details for Patent: 7,731,989

Title:	Gastric retained gabapentin dosage form
Abstract:	A method of treatment for epilepsy and other disease states is described, which comprises the delivery of gabapentin in a gastric retained dosage form.
Inventor(s):	Berner; Bret (El Granada, CA), Hou; Sui Yuen Eddie (Foster City, CA), Gusler; Gloria M. (Cupertino, CA)
Assignee:	Depomed, Inc. (Menlo Park, CA)
Filing Date:	Sep 26, 2008
Application Number:	12/239,591
Claims:	1. A dosage form, comprising between about 100 mg to about 4800 mg of gabapentin or pharmaceutically acceptable salt thereof, dispersed in a single polymer matrix comprising at least one swellable hydrophilic polymer that swells unrestrained dimensionally by imbibing water to increase its size to promote gastric retention of the dosage form in a stomach in a fed mode, wherein upon contact with water, gabapentin is released by diffusion from the dosage form over a period of at least five hours and at least 40 wt % of the gabapentin is retained in the dosage form 1 hour after administration. 2. The dosage form of claim 1 wherein the dosage form swells to approximately 115% of its volume prior to administration within one hour after administration. 3. The dosage form of claim 1, wherein the dosage form swells to approximately 130% of its volume prior to administration at a time later than one hour after administration. 4. The dosage form of claim 1, comprising between about 200-4000 mg gabapentin. 5. The dosage form of claim 1, comprising between about 200-2700 mg gabapentin. 6. The dosage form of claim 1, comprising between about 300-3600 mg gabapentin. 7. The dosage form of claim 1, comprising between about 500-3600 mg gabapentin. 8. The dosage form of claim 1, comprising between about 900-3600mg gabapentin. 9. The dosage form of claim 1, comprising between about 900-2400 mg gabapentin. 10. The dosage form of claim 1, wherein the gabapentin has a bioavailability greater than or equal to 80% of an equal dose of gabapentin in an immediate release dosage form. 11. The dosage form of claim 1, wherein the polymer matrix is comprised of a polymer having a molecular weight of between about 4.times.10.sup.3 to 1.times.10.sup.7 Daltons. 12. The dosage form of claim 1, wherein the swellable hydrophilic polymer comprises poly(ethylene oxide). 13. The dosage form of claim 12 wherein the poly(ethylene oxide) has a viscosity average molecular weight of between 2.times.10.sup.6 and 7.times.10.sup.6 Daltons. 14. The dosage form of claim 1, wherein the swellable hydrophilic polymer comprises hydroxypropylmethylcellulose. 15. The dosage form of claim 14, wherein the hydroxypropylmethylcellulose has a molecular weight such that a 1% aqueous solution has a viscosity at room temperature of between about 4,000-10,0000 centipoise. 16. The dosage form of claim 1, wherein the polymer matrix comprises poly(ethylene oxide) and hydroxypropylmethylcellulose. 17. The dosage form of claim 16 further comprising a lubricating agent. 18. The dosage form of claim 17 wherein the lubricating agent is magnesium stearate. 19. The dosage form of claim 1, comprising about 600 mg gabapentin. 20. The dosage form of claim 1, comprising about 300 mg of gabapentin.