Formulation and in vitro Evaluation of Gastroretentive Oral Matrix Tablets of Potential Anti- HIV Agent

The purpose of this research was to prepare and evaluate floating drug delivery system of Lamivudine. Floating matrix tablets of Lamivudine were developed to prolong gastric residence time and increase its bioavailability. Rapid gastrointestinal transit could result in incomplete drug release from the drug delivery system above the absorption zone leading to diminished efficacy of the administered dose. The tablets were prepared by direct compression technique, using polymers such as hydroxyl propyl methyl cellulose (HPMC E15), Ethyl cellulose and Xanthan gum combination and other standard excipients. Sodium bicarbonate was incorporated as a gas-generating agent. The effects of different concentrations of HPMC, EC and Xanthan gum on drug release profile and floating properties were investigated. Comparable release profiles between the commercial product and the designed system were obtained. The model fitting showed that the optimized formulation F2 formulations followed Korsmeyer and Peppas model, which had a higher value of correlation coefficient (r). While tablet hardness had little or no effect on the release kinetics and was found to be a determining factor with regards to the buoyancy of the tablets.