Formulation and Evaluation of Gastro Retentive Floating Tablets of Stavudine

The purpose of this research work was to develop gastroretentive drug delivery system of stavudine. Floating tablets were prepared by direct compression method using gas generating agents such as sodium bicarbonate and citric acid anhydrous, polymers like HPMC K4M, HPMC K15M and Xanthan gum. Formulations tried for different ratios of drug and polymers to get desired release profile. Prepared tablets (F1-F9) were evaluated in terms of precompression and postcompression parameters. Stavudine floating tablets were prepared by direct compression method were found to be good without chipping, capping and sticking. The drug content was uniform in all the tablet formulations indicating uniform distribution of drug within the matrices. All the prepared batches showed satisfactory floating lag time and total floating time found to be more than 24hrs. Among all formulations, F6 showed the drug release in most sustained manner and showed 98.434± 0.542 % of in vitro drug release at the end of 24 hrs and selected as the best formulation. The in vitro data obtained for the optimized formulation (F6) was fitted in different models viz. zero order, first order, Higuchi and Korsemeyer-Peppas equation for release kinetics and showed that the formulation follows Zero order release and the best fit model for the formulation was Korsemeyers-peppas model. Slope value (n) in Korsemeyer-Peppas equation for formulation was found as 0.7230 suggested that the release of stavudine from the formulation followed the non-Fickian transport mechanism. Further formulation F6 was subjected to accelerated stability studies for 3 months showed that formulation was intact without interaction. Finally optimized formulation F6 complying with all properties of floating tablets and found to be satisfactory.