Formulation and Evaluation of Extended Release Matrix Tablets for HIV Diseases

Abstract

Nevirapine is a virustatic drug has a very short half life and undergoes consider¬able first-pass metabolism thus necessitating an adequate zero order delivery. Objectives: The aim of the present study was to prepare and characterize extended release sustained tablets of Nevirapine (NVP) using hydrophilic (HPMC K4M). Methods: The FTIR and DSC studies confirmed that no chemical interaction took place in the final formulations. The scanning electron microscopy was used to visualize the effect of dissolution medium on matrix tablet surface. Release kinetics was evaluated by using United States Pharmacopoeia (USP)-23 type I dissolution apparatus. Results: The in-vitro drug release study of formulation with HPMC revealed that the sustained release was only for several hr. The effect of polymer on release profile of drug from matrix tablet was slow over 24 h. Drug release was by non-fickian diffusion mechanism. Resin encapsulated matrix tablet of NVP exhibited good controlled release characteristics and were found suitable for once a day oral controlled release products. Fitting the in-vitro drug release data to indicated that diffusion along with erosion could be the mechanism of drug release. Conclusion: In conclusion, the results suggest that the developed controlled release tablets of NVP with matrix could perform therapeutically better than tablets prepared with HPMC K4M, leading to improved efficacy and better patient compliance.