Formulation, Optimization and in Vitro Evaluation of Gastroretentive Mucoadhesive Microspheres of Furosemide

Objective: The objective of this study was to formulate and evaluate sustained release gastro retentive microspheres of furosemide using mucoadhesive polymers. It was expected that gastro retention plus mucoadhesion would contribute to extending the rate of drug release in the acidic medium in vitro, thereby projecting this formulation as a potential candidate for improvement of oral bioavailability of furosemide. Methods: Mucoadhesive microspheres of furosemide were formulated by ionic gelation method by using two opposite charge mucoadhesive polymers (cationic chitosan and anionic sodium alginate). The formulations were optimized by employing 22 Results: The microspheres formed were spherical in shape, and size ranged between 692-815 μm. Drug entrapment efficiency, % mucoadhesion and % drug release were ranged between 74.82-84.21 %, 22-43 % and 85.01-94.21 % respectively. DSC analysis revealed that there was no incompatibility between drug and excipients. The mechanism of drug release from microspheres followed Hixson-Crowell model. Comparison of drug release with marketed formulation (Lasix-40 factorial design and characterized for in vitro evaluation i.e. drug entrapment efficiency, mucoadhesion study, drug release study, swelling study, etc.