Effect of Method of Preparation on Physical Properties and in Vitro Drug Release Profile of Losartan Microspheres – a Comparative Study

Present investigation describes preparation of microspheres by solvent evaporation and W/O emulsion solvent evaporation methods followed by in vitro characterization of microspheres to evaluate the effect of method of preparation on physical properties and drug release profile of microspheres. The microspheres were found to be discrete, spherical with free flowing properties. The morphology (Scanning Electron Microscopy), particle size distribution, entrapment efficiency and their release profiles were investigated. The yield was found to be maximum in case of solvent evaporation method. The mean geometric particle size of microspheres prepared by solvent evaporation method was found in the ranges of 40-50 μm and the microspheres prepared by W/O emulsion solvent evaporation method was found in a ranges of 126-150 μm, respectively. The microcspheres formulation prepared by solvent evaporation method has shown greater encapsulation efficiency than W/O emulsion solvent evaporation method. The drug carrier interactions were investigated in solid state by Fourier Transform Infrared (FT-IR) spectroscopy study. In vitro drug release rate for microspheres was found to be sustained over 8 hours. Hence, it can be concluded that the formulation prepared by solvent evaporation method, has potential to deliver Losartan potassium in a controlled manner in a regular fashion over extended period of time in comparison to all other formulations and can be adopted for a successful oral delivery of Losartan potassium for safe management of hypertension. All data are verified as statistically significant by using one way ANOVA at 5 % level of significance (p < 0.05).