METHODS OF TREATMENT USING A GASTRIC RETAINED GABAPENTIN DOSAGE FORM

1 . A dosage form, comprising:

a core comprising gabapentin, and

a semipermeable membrane surrounding the core, the semipermeable membrane comprising a plasticizer and being permeable to a fluid in an environment of use and substantially impermeable to unsolubilized gabapentin,

wherein the dosage form has a size to promote retention in the upper gastrointestinal tract of a subject in a fed mode for a period of about 5 hours, and wherein at least about 80 wt % of the gabapentin is released from the dosage form in about 5-12 hours via controlled release through the semipermeable membrane.

2 . The dosage form of claim 1 , wherein the core comprises about 300 mg gabapentin.

3 . The dosage form of claim 1 , wherein the core comprises about 600 mg gabapentin.

4 . The dosage form of claim 1 , wherein the semipermeable membrane comprises a material selected from the group consisting of cellulose esters, cellulose ethers, polyalkylene oxides, polyvinyl alcohol, and polyvinylpyrrolidone.

5 . The dosage form of claim 4 , wherein the cellulose ether is selected from the group consisting of ethyl cellulose, hydroxyethylcellulose, hydroxypropylcellulose, and methylcellulose.

6 . The dosage form of claim 1 , wherein the plasticizer is selected from esters and fatty acids.

7 . The dosage form of claim 1 , wherein the dosage form further comprises a second therapeutic agent selected from the group consisting of a hydantoin, an iminostilbene, a valproate, a phenyltriazine, a barbiturate, a dexoybarbiturate, a benzodiazepine, a carbamate, an anticonvulsant other than gabapentin, a tricyclic antidepressant, levadopa, carbidopa, an opioid, lithium, carbamazepine, valproate, trifluoperazine, clonazepam, risperidone, lorazepam, venlafaxine, clozapine, olanzapine, a neuroleptic, a serotonin reuptake inhibitor, buproprion, nefadone, venlaxatine, nefadone, diazepam, oxazepam, a dopaminergic agent, clonazepam, a triptan and ergotamine.

8 . A method for treating epilepsy, psychiatric disorders, neuropathic pain or movement disorder, comprising

administering an extended release dosage form, comprising:

a core comprising gabapentin, and

a semipermeable membrane surrounding the core, the semipermeable membrane comprising a plasticizer and being permeable to a fluid in an environment of use and substantially impermeable to unsolubilized gabapentin,

wherein the dosage form is formulated to have a size to promote retention in the upper gastrointestinal tract of a subject in a fed mode for a period of about 5 hours, and wherein at least about 80 wt % of the gabapentin is released from the dosage form in about 5-12 hours via controlled release through the semipermeable membrane.

9 . The method according to claim 8 , wherein the dosage form provides for bioavailability of gabapentin at a level greater than or equal to 80% of that provided by an equal dose of gabapentin released by the immediate release dosage form as measured by the plasma AUC inf .

10 . The method according to claim 9 , wherein the gabapentin is released into the upper gastrointestinal tract over a period of about 5-12 hours at a rate sufficient to achieve a lower maximum plasma concentration (C max ) compared to an equal dose of gabapentin provided by an immediate release dosage form.