is used in the treatment of HIV and these are designed in such a way that release of the drug is for 10 to 12 hours. The Microspheres were prepared by the Solvent Evaporation method using varying concentrations of sustained release polymers Eudragit RS PO and Ethyl cellulose100cpc, Ethyl cellulose N22. The compatibility of the polymers was ruled out by FT-IR studies and found to be compatible. Total 15 formulations were prepared. The Efavirenz microspheres were evaluated for their physical properties like angle of repose, bulk density and swelling index and found to have good flow property. The prepared microspheres were evaluated for in process and finished product quality control tests including appearance, Bulk density, Entrapment efficiency and in- vitro drug release. The dissolution medium used was pH 7.0 phosphate buffer. All formulations showed acceptable pharmaco-technical properties and complied with in-house specifications for tested parameters. The results of dissolution studies indicated all formulations released up to 12hours and formulation containing Eudragit RS PO i.e. F14 was the most successful formulation with 96.82% drug release at the end of 12 hours.
