Valsartan release from sustained release matrix tablet and effect of cellulose derivatives

Abstract

The present study was aimed to develop antihypertensive sustained release matrix tables of valsartan Angiotensin II receptor antagonist, using hydroxypropylmethylcellulose alone and in combination with ethyl cellulose as the matrix material in different proportion by wet granulation method. The granules were evaluated for angle of repose, bulk density and Compressibility index. The tablets were subjected to weight variation test, drug content, hardness, friability, and in vitro release studies. The granules showed satisfactory flow properties, compressibility, and all the tablet formulations showed acceptable pharmacotechnical properties. The formulated tablets also compared with a marketed product. In vitro dissolution studies indicate that EC significantly reduced the rate of drug release compared to HPMC. But no significant difference was observed in the release profile of matrix tablets made by higher percentage of EC. The result of dissolution study indicate that the formulation prepared by low viscosity grade HPMC (H1and H2) showed maximum drug release up to 8 hrs and high viscosity gread HPMC and EC formulation (H3 to H6) showed upto 12 hrs. In case of formulation containing combination of HPMC and EC (F1 to F4) prepared using factorial design, showed drug release up to 24 hrs, whereas marketed product was found to be release up to only 3 hrs.Methematical treatment of the in vitro drug release data suggest that, optimized formulation F3 fitted in to Korsmeyer and Peppas release kinetic shows R² value 0.9930. Drug release from the matrix occurred by combination of two mechanism, diffusion and erosion of tablet.