THEOPHYLLINE TABLETS COATED WITH AQUEOUS LATEXES CONTAINING DISPERSED PORE FORMERS

Constant drug release was achieved from theophylline tablets coated with a multiporous membrane in an aqueous environment. The tablets were coated with an aqueous acrylic latex containing a dispersed pore‐forming agent with pH‐dependent solubility characteristics. The pore former, dibasic calcium phosphate, was insoluble in the latex but leached put rapidly in 0.1 M HCI. Theophylline was then released at a constant rate through the multiporous membrane. The drug release was a function of the level of the pore‐forming agent and the membrane thickness, but independent of the pH of the dissolution medium and the degree of agitation. Copyright © 1990 Wiley‐Liss, Inc., A Wiley Company