Formulation of multilayered sustained release tablets using insoluble matrix system

In an attempt to provide sustained release of ephedrine hydrochloride, the multilayered tablet concept was utilized having a loading dose of 20 mg and a maintenance dose of 40 mg formulated in an insoluble matrix system. Several formulations having ethyl cellulose and Eudragit RS 100 were tried. Eudragit RS 100 alone did not yield good results. However, a combination of ethyl cellulose and Eudragit RS 100 retarded the release considerably. Drug release from all the tablets followed first order kinetics.