Patent ID: 6511678
Filing Date: 2003-01-28
Classification: A61K

Abstract:
An oral hydrophilic matrix formulation suitable for once-a-day administration comprising:a) from about 40 to about 80 w/w % of divalproex sodium; b) said divalproex sodium is in admixture with about 20 to about 50 w/w % of a pharmaceutically acceptable hydrophilic polymer selected from the group consisting of polyvinylpyrolidine, hydroxypropyl cellulose, hydroxypropylmethyl cellulose, methyl cellulose, vinyl acetate copolymers, polyethyleine oxide, methacrylic acid copolymers, and maleic anhydride/methyl vinyl ether copolymers, and; c) said formulation exhibits the following in-vitro dissolution profile, when measured in a type 2 dissolution apparatus, paddle, at 100 rpm, at a temperature of 37+0.5 C., in 500 ml of 0.1N HCl for 45 minutes, followed by 900 ml of 0.05M phosphate buffer containing 75 mM sodium laurel sulfate, pH 5.5, for the remainder of the testing period: i. no more than about 30% of total valproate is released after 3 hours of measurement in said apparatus; ii. from about 40 to about 70% of total valproate is released after 9 hours of measurement in said apparatus; iii. from about 55 to about 95% of total valproate is released after 12 hour of measurement in said apparatus, and; iv. not less than 85% of total valproate is released after 18 hours of measurement in said apparatus.