Preparation and In vivo Evaluation of Mucoadhesive Microspheres for Gastroretentive Delivery of Misoprostol

The aim of the present investigation was to prepare and evaluate the Misoprostol mucoadhesive microspheres for gastroretentive drug delivery. Sodium alginate and sodium carboxy methyl cellulose were used as mucoadhesive polymers. Microsphere formulations were prepared using Ionotropic gelation technique. All the microspheres were characterized for particle size, scanning electron microscopy, FT-IR study, percentage yield, drug entrapment, stability studies and for in vitro release kinetics. Based on the results, the formulation M12 was selected as optimized formulation. In vitro drug release study of optimized formulation M12 showed 98.23% after 12 h in a controlled manner, which is essential for anti ulcer therapy. The marketed product shows the drug release of 95.23 within 1 h. The results of mucoadhesion study showed better retention of prepared microspheres (8) h in chic duodenal and jejunum regions of intestine. The results showed significant higher retention of mucoadhesive microspheres in upper GI tract. Pharmacokinetic study revealed that the bioavailability was found to be increased significantly when compared with marketed tablets. The drug release of Misoprostol optimized formulation M12 followed zero order, Higuchi and Korsmeyer-Peppas kinetics indicating diffusion controlled with non-Fickian (anomalous) transport thus it projected that delivered its active ingredient by coupled diffusion and erosion. Overall, the result indicated prolonged delivery with improved bioavailability of Misoprostol from mucoadhesive microspheres due to higher retention in the upper GI tract.