Formulation Development and Evaluation Bilayer Floating Sustained and Immediate Release Tablet of Verapamil Hydrochloride by Direct Compression Method

Abstract

In the current study a successful attempt was made to formulate Bilayer Floating tablets of Verapamil Hydrochloride by direct compression method containing loading dose, superdisintegrants in immediate release layer and maintenance dose, rate controlling polymers and gas generating agents in floating layer. Floating tablets of Verapamil Hydrochloride was prepared using HPMC K4M, HPMC K15M and Xanthum gum in different ratios for optimizing the floating layer of bilayer floating tablets. The optimized floating tablets which was used further to formulate bilayer floating tablets contains HPMC K4M or HPMC K15M and Xanthum gum in the ratio of 3:2 showed shortest buoyancy lag time with more than 24 h total buoyancy time and in-vitro drug release was more rapid compared to floating tablets containing Xanthum gum, HPMC K4 M, HPMC K15 M alone. Various physicochemical properties of Bilayer floating tablets were within the pharmacopoeial limits thus showing good mechanical strength and content uniformity of tablets. The relative efficiency of superdisintegrants in enhancing the disintegration and dissolution rates of tablets was found to be in the following order: Crosscarmellose sodium > Sodium starch glycolate > Micro crystalline cellulose. Formulation BLF2 containing 5% Crosscarmellose sodium in the immediate release layer, HPMC K4M and Xanthum gum in the ratio of 3:2 in the floating layer showed highest in-vitro drug release and it followed Higuchi as predominant mechanism of drug release. Therefore, it was considered as the best formulation.