Abstract

Different retardant polymers including Carbopol 934P, HydroxyPropyl Methyl Cellulose (HPMC) (Methocel K4M) and Eudragit@ NE30D, RL30D and RS30D as release controlling materials were evaluated. The drug release medium consisted of hydrochloric acid buffer, pH-1.2, for the first two hours and phosphate buffer, pH-6.8, for the remaining period of time during the experiements. The influence of variables including polymer type, drug: polymer ratio, tablet filler type and tablet hardness on isosorbide dinitrate (ISDN) release profile was discussed. From the retardant polymers investigated, Eudragit NE30D exhibited proper release characteristics. The pattern of drug release from formulation prepared from Eudragit NE30D was shown to corespond to the Higuchi equation. According to the equation, M(t)/M(oo)=k.t(n), ISDN release mechanism from Eudragit NE30D matrix tablets (40 mg) was based on non-Fickian-Diffusion process. It was also realized that, matrix preparation was a suitable method for the formulation of ISDN-CR tablets.