Abstract
The investigation is aimed to study the effect of different viscosity grades of Hydroxypropyl methylcellulose (HPMC K4M, K15M, K100M) at different concentration on the release rate of two drugs with different aqueous solubility, that is freely water soluble drug Propranolol hydrochloride and practically water insoluble drug Valsartan. Hydrophilic matrix tablets containing 80 mg of drug and 10%, 15% 30%, 45% and 60% w/w of each of the three grades of the polymer were fabricated for both the drugs respectively. Formulations were evaluated with respect to drug release studies for 24 hours and rate kinetics study was done on each formulations. The result indicated that of the various viscosity grades of HPMC, HPMC K15 was able to better control the release for both water soluble and insoluble drug at desired rate for 24 hrs. For water soluble Propranolol hydrochloride HPMC K15M concentration required to give desired release profile is 45% of tablet weight and for the insoluble drug Valsartan the HPMC K15M concentration needed to get desired release profile is 15%. The Peppas release kinetic model defined the drug release for the optimized Propranolol HCl controlled release formulation indicating non Fickian diffusion. For Valsartan, the Hixon Crowell model best defined the release rate kinetics.
