Formulation and In vivo Evaluation of Mucoadhesive Microspheres of Valsartan using Natural Gum

Abstract

Microspheres containing valsartan were prepared by the ionotropic gelation method, using sodium alginate with other mucoadhesive polymers namely HPMC K 100M and Eudragit RL 100, Olibanum gum and Guar gum. The prepared batches were evaluated for different evaluation parameters. The in vitro drug release of optimized formulation M13 showed the sustained release of Valsartan up to 98.89 ± 5.25% within 12 h whereas marketed product displayed the drug release of 90.99 ± 4.96%. The release mechanism from microspheres followed the zero order and higuchi model (R2 = 0.988, 0.979) respectively. The optimized formulation (M13) shown % entrapment efficiency, % yield, swelling index and mucoadhesiveness of 98.18, 97.64, 97.42 and 96.18% respectively. From FTIR studies no incompatibility was found between drug and excipients. SEM confirmed that particles were of spherical in shape. Optimized formulation (M 13) was stable at 40°C ± 2°C/75% RH ± 5% RH for 6 months. From in vivo bioavailability studies, valsartan optimized formulation M13 exhibited sustained release in a controlled manner when compared with marketed product. Mean time to reach peak drug concentration (Tmax) was 4.00 ± 0.05 h and 3.00 ± 0.04 h for the optimized and marketed product respectively, while mean maximum drug concentration (Cmax) was 10.85 ± 0.03 ng/mL and 8.54 ± 0.01 ng/mL respectively. AUC0–∞ of optimized formulation was found to be 147.42 ± 1.16 ng.h/mL, when compared with marketed product of 119.15 ± 1.13 ng.h/mL, AUC values of optimized formulation were found to be significantly higher (p<0.05) than of marketed product. Valsartan muco-adhesive microspheres would be a promising drug delivery system, could play a potentially significant role in pharmaceutical drug delivery in the treatment of hypertension.   &nbsp