FORMULATION DEVELOPMENT AND EVALUATION OF SUSTAINED RELEASE MATRIX TABLETS OF VERAPAMIL HYDROCHLORIDE

Sustained release matrix tablets reduce the frequency of the dosing and increase the effectiveness of the drug by localization at the site of action, providing uniform drug delivery. Sustained release matrix tablets of verapamil hydrochloride were prepared by using HPMC K15M, Xanthan and Guar Gum polymers with different concentration in various batches of the formulations to facilitate the drug release which cause patient compliance as the dosing frequency is reduced. Verapamil HCl was considered as an ideal drug for designing sustained release formulation because of the high frequency of administration and short biological half-life. The sustained release matrices of Verapamil HCl were prepared by wet granulation technique. Drug release was studied by using Dissolution testing apparatus 2 (paddle method)  with 0.1 N HCl buffer for 2 hours followed by pH 6.8 Phosphate buffer for 8 hours. The in vitro drug release of various formulations was performed and compared. The results shows that the tablets formulated with HPMC K15M polymer shows more sustained action when compared to that of Xanthan and Guar gum. The high viscosity of the polymers binds the formulation of matrix thus sustains the release of drug. It was also observed that the increase in concentration of the polymer decreased the drug release from the polymer matrix.