Preparation of Nimodipine Loaded Microspheres: Evaluation of Parameters

The purpose of this study was to prepare and characterize nimodipine loadedmicrospheres using ethyl cellulose (ec) as a carrier polymer through an emulsionsolvent evaporation method. these evaluations characterized the pattern of drugrelease from prepared microspheres. nimodipin loaded microspheres were preparedusing an emulsification solvent evaporation method. the effect of process variablessuch as stirring rate, drug polymer ratio in the organic phase, the viscosity of thedispersed phase and the emulsifier concentration, on the morphology of microspheres,particle size distribution, drug content and in vitro release profile of nimodipine wereinvestigated. the prepared microspheres were spherical with smooth surface. themean diameter of microspheres decreased with increasing the concentration of theemulsifier in the continuous phase and stirring rate of the medium. however,increasing the viscosity of the dispersed organic phase increased the particle sizeof microspheres. both the drug and polymer concentration in the organic phaseincreased the entrapment of nimodipine in ethyl cellulose microspheres. drugcontent of the microspheres was lowered by increasing the viscosity of the dispersedphase and increasing the concentration of poly vinyl alcohol. the rate of drugrelease from microspheres was directly influenced by the drug to polymer ratio, asany increase in this ratio allowed the higher release rates from microspheres. thehigher the polymer concentration the lower was the rate of drug release frommicrospheres.