Formulation, optimization and evaluation of mucoadhesive microspheres of captopril

Abstract

The objective of the present study was to develop mucoadhesive microspheres of captopril in order toachieve extended retention in upper gastro intestinal tract to enhance absorption and bioavailability. The microsphereswere prepared by emulsification method using different ratio of sodium alginate with captopril by cross-linking withcalcium chloride. Fourier-transform infrared spectroscopy study shows that captopril and other excipients arecompatible with each other. The effects of polymers concentration on drug release profile were investigated. Responsesurface methodology was applied to systemically optimize the drug release profile. Polymer to drug ratio and stirringspeed were selected as independent variables. Drug entrapment efficiency, percentage mucoadhesive and in vitro drugrelease after 6 hours were selected as dependent variables. Obtained microspheres were subjected to differentevaluation parameters such as percentage yield, particle size analysis, drug entrapment efficiency, percentagemucoadhesive, in vitro drug release, drug release kinetics and scanning electron microscopy. The optimized formulation(MM10) showed satisfactory drug entrapment efficiency of 80.34±1.8 %, percentage mucoadhesive of 95.75±1.2 andpercentage drug release after 6 hours of 26.08±0.45 %. Scanning electron microscopy analysis revealed that particleswere spherical with smooth surface. Particles were free flowing with average particle size of 51.43 μm. Better resultswere observed from optimized mucoadhesive microspheres of captopril, thereby improving the bioavailability due toprolong release of drug in stomach.