FORMULATION, EVALUATION AND OPTIMIZATION OF FLOATING MATRIX TABLETS OF CARVEDILOL

Bilayer floating tablets were prepared by direct compression using HPMC K100M and Ethyl cellulose as the release controlling polymers and sodium bicarbonate as a gas generating agent. The optimum concentrations of the above ingredients were determined under experimental conditions and on the basis of trial batches of the tablets. In the present study bilayer tablet was prepared manually using single station punching machine. Accurately weighed 150mg of sustained release layer powder mixture was fed manually into die cavity. Sustained release layer was compressed at mild compression force (2-3 kg/cm2 ). After that accurately weighed 100mg of immediate release powder mixture was manually fed into the die over sustained release layer and compressed. Eleven formulations were prepared and evaluated for various evaluation parameters of bilayer tablet for physical properties, floating and in vitro drug release. All the formulations showed optimum flow properties, percentage of weight variation and friability. Accordingly, the increase of sodium bicarbonate from 0.5 to 9 % in the polymer resulted in a decrease in FLT from 9 to 1 min (F1-F3). Because of the amount of sodium bicarbonate also affected the drug release from the formulation, F2 have optimum concentration (4.5%) of sodium bicarbonate. The drug release pattern and drug uniformity were found to be satisfactory. Considering the in vitro drug release studies batch F9 was selected as optimized formulation Keywords: Bilayer floating matrix tablet, carvedilol, HPMCK100M, Sodium bicarbonate, sodium starch glycolate