Formulation and Evaluation of Floating Sustained Release Tablets of Valsartan for Gastro-Retentive Drug Delivery

摘要

The purpose of this research was to formulate and evaluate the Floating sustained release tablets of Valsartan 200mg, an anti hypertensive drug. Valsartan is a type I angiotensin II receptor antagonist. The tablets are prepared by direct compression method. The formulations was optimized by incorporating varying composition of HPMC K15, K100, E5 and MCC as diluent, Sodium bicarbonate, Citric acid as floating agents, Magnesium sterate agent as lubricant. All the excipients are tested for compatibility with drug, which revealed that there was no physical and chemical interaction occurred. The Preformulation parameters such as bulk density, tapped density, compressibility index and Hausner's ratio were analyzed. The thickness, hardness, friability, weight variation, disintegration time and drug content uniformity was evaluated for core tablets. The effect of these variables on drug release also studied. The In-Vitro drug release studied were Performed in the USP dissolution apparatus-II (paddle) using 0.1N HCL buffer as dissolution media at 100 rpm speed and temperature of 37oc ± 5oc. the sampling was done at periodic time intervals of 1,4,8,12,16,20 and 24 hours and was replaced by equal volume of dissolution media after each withdrawal. The cumulative amount of drug release at different intervals is estimated using UV spectrophotometer. Based on the evaluation result the formulations F-5 containing HPMC K.15 were selected as best formulation. The tablets was found to follow Zero order kinetics and Higguchi mechanism of drug release, 'n' value is less than 0.5 which confirms that the drug release through the matrix was fickian diffusion.