Patent ID: 6492488
Filing Date: 2002-12-10
Classification: A61K,B29B,B29K,C08J

Abstract:
A method for making a controlled release tablet comprising the steps of:converting a polyacrylic acid in a readily water swellable form from a fine powder to a granular form that is also readily water swellable by (a) delivering a fine powder of anhydrous polyacrylic acid to a compaction device; (b) compacting said polyacrylic acid powder into larger agglomerates and/or aggregates, (c) fracturing said polyacrylic acid agglomerates and/or aggregates into said granular form; and (d) optionally screening said polyacrylic acid granules to obtain the desired particle size range by removing or recycling in said process oversized and/or undersized granules, said polyacrylic acid being a polymer derived from one or more monomers having at least 50 mole percent repeating units containing a carboxylic acid group and/or an anhydride of dicarboxylic acid and said polyacrylic acid having a viscosity of at least 500 centipoise when dispersed in water and neutralized to a pH of 7 at a concentration of 10 g/L; said polyacrylic acid polymerized by precipitation polymerization in a non-aqueous medium; formulating a tablet blend comprising i) a material to be released in a controlled manner, ii) said granular polyacrylic acid in a readily water swellable form, and iii) conventional tablet formation adjuvants; and forming and compressing the tablet blend into a tablet.