No abstract

A multiparticulate drug delivery system was studied in which the drug release of a model drug theophylline could be modulated by interactions of ammonio methacrylate polymer and anions. The system consisted of a EUDRAGIT NE coated anionic core, layered with drug and further layered with EUDRAGIT RS. The effects of different anions like chloride, succinate, citrate, and acetate as well as the thickness of the polymer layers on the in vitro drug release were studied. It was seen that succinate and acetate anions had permeability enhancing effects and citrate and chloride anions had permeability retarding effects on the polymer. The results indicate that changing these variables would enable us to get a desired release profile and hence the proposed system could be a viable alternative to existing technologies for the development of a controlled drug delivery system.