Development of Solid Self Emulsifying Drug Delivery Systems Containing Efavirenz: in Vitro and in Vivo Evaluation

Efavirenz is a drug with an absorption window. Its oral bioavailability is 40-50%. The aim of this work was to formulate solid self-emulsifying drug delivery system to improve the solubility and bioavailability of efavirenz. Solubility of Efavirenz was determined in various vehicles like oils, surfactants and co surfactants. Which, upon dilution with aqueous media, spontaneously form fine oil in water (micro) emulsion with less than 300 nm in droplet size. Pseudoternary phase diagrams were constructed to identify the self (micro) emulsifying region. Seven S(M)EDDS formulations were prepared. The optimized liquid self-emulsifying drug delivery system formulation (F3) was converted into solid S(M)EDDS with free flowing powder by adsorbing onto a solid carrier like Neusilin US2 for encapsulation. X-ray diffraction studies showed no physicochemical interaction. The in-vitro dissolution characteristics and in-vivo bioavailability studies of optimized formulation and reference standard confirmed that better systemic absorption and bioavailability also found to be increased with optimized formulation.