PH INDEPENDENT EXTENDED RELEASE PHARMACEUTICAL FORMULATION

PROBLEM TO BE SOLVED: To provide a pharmaceutical formulation of acidic pharmacologic agent which demonstrates improved uniformity of release over the wide range of pH values encountered between the stomach and intestinal tract.SOLUTION: The pharmaceutical formulation of acidic pharmacologic agent comprises an acidic pharmacologic agent dissolved or dispersed in a matrix comprising about 10-40 wt.% of a neutral water-swellable hydrophilic polymer and 20 wt.% to about 50 wt.% of an acid-soluble polymer which swells in water at pH values above about 5. A particularly preferred formulation comprises divalproex sodium. There are also provided a pre-tablet granulation and a method for producing both the pre-tablet granulation and the tablet unit dosage form.