FABRICATION AND EVALUATION OF GASTRORETENTIVE FLOATING MATRIX TABLETS OF NEVIRAPINE
The present study was carried out in fabricating gastro retentive formulation of Nevirapine using semi synthetic and natural polymers. Floating tablets were prepared by direct compression method using directly compressible microcrystalline cellulose as vehicle. Gum Xanthan and hydroxypropyl methylcellulose (HPMC E4M) were used as polymers for sustaining the drug release and sodium bicarbonate was used as an effervescent agent. Tablets were characterized for their pre compression and post compression parameters. Floating characteristics like floating lag time, floating time were evaluated and were considered as one of the factor for selecting the best formulation. The in vitro release studies were carried out in pH 1.2 buffer for 8hrs. The content uniformity was found to be within the compendial requirements and the release was extended for more than 8hrs. The best fit release kinetics was achieved with zero order followed by higuchi and non-fickian diffusion. The release of Nevirapine was significantly influenced by the concentration of polymer