The objective of present study is to formulate and optimize the self emulsifying drug formulations systems of nevirapine by use of 22 factorial designs to enhance the oral absorption of nevirapine by improving its stability, solubility, dissolution rate and diffusion profile. SEFS are the isotropic mixtures of oil, surfactant, co-surfactant and drug that form oil in water micro emulsion when introduced into aqueous phase under gentle agitation. Solubility of nevirapine in different oils, surfactants and co-surfactants was determined for the screening of excipients. Pseudo-ternary phase diagrams were constructed by the aqueous titration method and formulations were developed based on the optimum excipient combinations with the help of data obtained through the maximum micro emulsion region containing combinations of oil, surfactant and co-surfactant. The formulations of SEFS were optimized by 22 factorial designs. The optimum formulation of SEFS contains 32.5% oleic acid, 44.16% tween 20 and 11.9% PEG 600 as oil, surfactant and co-surfactant respectively. The SEFS were evaluated for the following drug content, self-emulsification time, rheological properties, zeta potential, in-vitro diffusion studies, thermodynamic stability studies and in-vitro dissolution studies. An increase in dissolution was achieved by SEFS compared to pure form of nevirapine. Overall, this study suggests that dissolution and oral bioavailability of nevirapine could be improved by SEFS technology.
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