FORMULATION AND EVALUATION OF GASTRORETENTIVE FLOATING DRUG DELIVERY SYSTEM OF AMLODIPINE

Abstract

Amlodipine has been the most widely used drug for the treatment of high blood pressure or chest pain (angina) and other conditions caused by coronary artery disease. The present investigation concerns the development and evaluation of floating tablets of amlodipine which after oral administration, are designed to prolong the gastric residence time, increase drug bioavailability and sustain the drug release. A 32 full factorial design was employed to evaluate contribution of HPMC (K4M/K15M) ratio (polymer blend) and sodium bi carbonate on floating lag time and drug release for 24 hrs. The tablets were prepared by direct compression method and further evaluated for pre compression parameters, physical characteristics, buoyancy, lag-time, swelling index and in vitro release using USP 24 basket type dissolution apparatus using pH 1.2 as a dissolution medium. Multiple regression analysis was performed for factorial design batches to evaluate the response. All formulation had floating lag time below 3 min and constantly floated on dissolution medium for 24 hrs. The optimized formulations were subjected to various kinetic models and it was found that the mechanism of drug release was predominantly diffusion in combination with polymeric relaxation. The best formulation remained buoyant and showed a sustained drug release for 24 hrs.