Preparation and Evaluation of Self-nanoemulsifying Formulation of Efavirenz

Efavirenz is an antiretroviral drug which exhibits lower absorption in gastric fluid due to poor water solubility characteristics. Self-nanoemulsifying drug delivery systems (SNEDDS) were designed with the objective of improving the solubility and dissolution rate of the drug. Solubility of efavirenz was determined in various vehicles, which includes oils (/modified oils), surfactants and co-surfactants. Pseudo-ternary phase diagrams were constructed to identify the most efficient selfemulsification region. Based on the solubility labrafac PG(oil), tween 80 (surfactant), PEG 200 (Cosurfactant) were selected for preparation of SNEDDS. FTIR spectroscopy was performed in order to investigate the interaction between any of the ingredients used in the formulation. The prepared formulations were evaluated for thermodynamic stability (centrifugation, heating cooling cycle (H/C cycle), freeze thaw cycle), dispersibility, robustness to dilution, particle size measurements, zeta potential, refractive index, percent transmittance, viscosity, drug content and In vitro drug release. The FTIR data confirms that there is no interaction between the drug and the excipients. The optimized efavirenz SNEDDS contains labrafac PG(15%), Tween 80(19%) and PEG 200(38%) which shows mean globule size of 142.8 nm. In vitro drug release of the formulation was found to be 97.4 % in 20min whereas pure drug shows only 22.4% at the end of 30 min. The stability study of prepared SNEDDS shows same physicochemical properties as compare to initial SNEDDS after 3 month storing in stability chamber at 40°C and 75%RH