FABRICATION DEVELOPMENT, OPTIMIZATION AND CHARACTERIZATION OF GASTRORETENTIVE MICROSPHERES OF AN ANTIHYPERTENSIVE DRUG

Abstract

The objective of the present study was to develop floating microspheres of Captopril in order to achieve an extended retention in the upper GIT which may enhance the absorption and improve the bioavailability. In the present study, preparation of captopril floating microspheres, evaluation of Floating Drug Delivery System (FDDS) in vitro, forecast of the release, and optimization of stirring speed and polymers ratio to match target release profile was investigated. The microspheres were prepared by solvent evaporation method using different ratio of hydroxyl propyl methyl cellulose (HPMC K4M) with drug in the mixture dichloromethane and ethanol at ratio of (1:1), with tween80 as the surfactant. Differential Scanning Calorimeter (DSC) study shows that drug and other excipients are compatible with each other. The effects of polymers concentration on drug release profile were investigated. The floating microspheres were characterized by and results obtained are % yield, particle size analysis, drug entrapment efficiency, surface topography, buoyancy percentage, in-vitro drug release was studied for 12 hour and scanning electron microscopy. Accelerated stability study was also performed for three months indicated that optimized formulation was stable. The floating microspheres showed better result and it may be use full for prolong the drug release in stomach and improve the bioavailability. The outcome showed that the polymer ratio and stirring speed affected the size, incorporation efficiency and drug release of microspheres (> 12 h), floating time (> 12 hr) and the best results were obtained at the ratio of HPMC K4M: EC (1:6). The mean particle size of prepared floating microspheres increased but the drug release rate from the microspheres decreased as the polymer concentration increased. The developed floating microspheres of captopril may be used for prolonged drug release for at least 12 hrs, thereby improving the bioavailability and patient compliance. Key words: Floating microspheres (FDDS), captopril, hydroxyl propyl methyl cellulose, ethyl cellulose, in-vitro release studies, bioavailability.