Effect of Croscormellose Sodium in Sustained Release Layer of Valsartan in Bilayer Tablet with Clopidogrel as Immediate Drug Release and Valsartan as Sustained Drug Release

Abstract

The aim of the study was to design and evaluate bilayer tablets of clopidogrel as immediate release and quick relief and valsartan for sustained release and check the effect of croscarmellose sodium (2%) in Carbopol for sustained release action. Bilayer tablets was prepared using direct compression method. Super disintegrants such as Crospovidone, Croscarmellose sodium were evaluated for immediate release of clopidogrel. Polymers HPMC K4, guar gum, ethyl cellulose and carbopol for controlling release of Valsartan. The compressed bilayer tablets were evaluated for weight variation, thickness, hardness, friability, drug content and in vitro drug release in 0.1N HCl and phosphate buffer pH 6.8. All the pre and post compression parameters were found to be within the acceptable limits. The formulations were optimized based on results of dissolution and formulations CF5 for immediate release & VF11 for sustained release. VF11 was formulated with addition of superdisentigrant and showed better controlled release and dissolution similar to VF8. The release kinetics of Valsartan was subject to curve fitting analysis in order to identify the best fit kinetic model. The regression analysis proves that VF11 follow first order release and drug release by diffusion process based on Fick’s law of diffusion. The data for stability studies infer no considerable change in drug content, dissolution rates and other quality control test were within limits.
 Keywords: Bilayer tablets, clopidogrel, valsartan, direct compression method.