Efavirenz Loaded Mixed Polymeric Micelles: Formulation, Optimization, and In Vitro Characterization

Efavirenz (EFZ) is a biopharmaceutics classification system (BCS) Class-II, first-line antiretroviral (ARV) drug. However, its utility through the oral route is restricted by its poor solubility. The objective of this study was to formulate EFZ-loaded binary-mixed micelles as a potential carrier for oral administration of EFZ. Rubingh's regular solution theory was used to determine the interaction behavior of the two components (Cremophor RH 40 and Phospholipon 80H) and of the mixed micelles and synergistic behavior was confirmed. The mixed miceller system was formulated using solvent evaporation method and a 3(2) factorial design was used for the optimization of selected independent variables. Miceller systems were further characterized in terms of morphology, particle size, zeta potential, percent entrapment efficiency, and drug loading. Fourier transform infrared and differential scanning calorimetry measurements confirmed the entrapment of EFZ in the micelles. The optimized formulation presented desirable qualities viz., nanometric size (17.27 +/- 0.079), high entrapment efficiency, and good colloidal stability. The prepared optimized micelles can be potential carriers for EFZ in ARV therapies.