Studies on Bio-adhesion of Matrix Tablets: I. Release Profile of Theophylline Anhydrous

Abstract

Controlled release matrix tablets of theophylline anhydrous were designed with different types of bioadhesive polymers. HPMC 15 cps and 50 cps, Na-CMC, Gelatin, Xanthun gum and PVP K-30 were selected to formulate matrix tablets. Tablets of theophylline were prepared by direct compression method and were subjected to in vitro drug dissolution for 8 hrs in a gastric fluid media by using thermal shaker with a shaking speed of 50 rpm at a temperature of 37 ± 0.5°C. The in vitro release study as well as retention time of bioadhesive tablets on mucous membrane were investigated to develop a bioadhesive polymer based controlled release delivery system and to evaluate the performance of such delivery device. Na-CMC, HPMC and Xanthan gum based tablets showed greater bio-adhesive strength where as gelatin and PVP K-30 based tablets showed poor bioadhesive strength. Na-CMC and Xanthun gum loaded tablets were not discharged from the mucous membrane and these tablets were fully dissolved in the gastric fluid. Xanthan gum, Na-CMC and HPMC based formulation showed nearly zero-order release. On the contrary, gelatin and PVP K-30 based formulation showed a burst release within one hour of dissolution.