Formulation, Characterization and In-vitro Evaluation of Abacavir Sulphate Loaded Microspheres

The aim of the present investigation was to formulate, characterize and evaluate Abacavir Sulphate (AS) loaded microspheres. Microspheres were prepared by emulsion – solvent evaporation method, using Ethyl cellulose, HPMC K4M, Eudragit RSPO and Eudragit L 100 in different combinations and proportions, in order to achieve better controlled release. The entrapment efficiency of all the formulations was found to be in the range of 79.45±7.71 to 89.79± 5.47%. The encapsulation efficiency was also found to be dependent on nature of polymer used in the formulation. Scanning electron microscopic analysis confirmed the formation of discrete, spherical, free flowing microspheres with a size range of 25.69±10.55μm to 37.93±26.39μm. All the formulations (F1-F8) exhibited anomalous diffusion mechanism and followed zero order kinetics. The formulation coded as F2 prepared with HPMC K4M was selected as best formulation showed 94% of drug release at the end of 24 hours with best Physico-chemical properties. Therefore such a design can be used for the controlled delivery of AS in the form of microspheres for the treatment of HIV. Stability of the optimized formulation revealed promising results when stored under refrigeration and room temperature.