In the present study an attempt has been taken to develop esomeprazole sustained release matrix tablet using hydroxypropyl methylcellulose (HPMC) polymer such as Methocel K4M CR by direct compression method. Various amount of Methocel K4M CR was used to develop matrix builder in the seven proposed formulations (F1-F7) for the study of release rate retardant effect at 20%, 25%, 30%, 35%, 40%, 45% and 50% of total weight of tablet matrix respectively. The granules were evaluated for angle of repose, loose bulk density, tapped bulk density, compressibility index, total porosity, and drug content. The prepared tablets were subjected to thickness, weight variation, hardness, friability measurements, drug content determination and in vitro release studies. The granules showed satisfactory flow properties, compressibility and drug content. All the tablet formulations complied with pharmacopoeial specifications for tested parameters. The dissolution study were conducted in the simulated gastric medium (pH 1.3) for first two hours and then in the simulated intestinal medium (pH 6.8) for 8 hours using USP dissolution apparatus II. From in vitro dissolution study, the formulation F-5 (40%) and F-6 (45%) met the official release pattern of esomeprazole for lOh period. The release mechanisms were explored and explained by Zero order, Higuchi, First order and Korsmeyer-Peppas equations. The release kinetics of formulation F-5 and F-6 very closely followed Higuchi kinetic order than first order and zero order kinetics. From Korsmeyer- Peppas equation it was found that the drug release followed both diffusion and erosion mechanism in all cases.

Keywords: Esomeprazole, Direct compression, Sustained release, Methocel K4M CR, Release Kinetics.