ABSTRACT:
The present study was aimed at preparing a Floating matrix drug delivery system for the model drug Labetalol Hydrochloride, and evaluating the various processing parameters including the buoyancy studies and in vitro drug release studies. Floating matrix tablets of Labetalol hydrochloride were developed to prolong gastric residence time and increase its bioavailability. Floating matrix tablets containing 85 mg Labetalol Hydrochloride were developed using different polymer combinations. Seven formulations containing varying proportions of polymers like HPMC K4M and Carbopol 934 P, Sodium carboxy methyl cellulose and fixed amount of gas generating agent such as Sodium bi carbonate were prepared. The tablets were prepared by direct compression technique. The formulations were optimized on the basis of acceptable tablet properties, floating lag time, total duration of floating and in vitro drug release. The prepared tablets remained buoyant for 17 hrs in the release medium. The results of dissolution studies, floating lag time indicated that formulations S1 exhibited good and controlled drug release. Applying the linear regression analysis and model fitting showed the selected formulation S1 showed diffusion coupled with erosion drug release mechanism, followed zero order kinetics. Optimized floating matrix tablets S1 showed no change in physical appearance, drug content, or in vitro dissolution pattern after storage at 40°C / relative humidity 75% for a period of 3 months.