Objective: Microemulsions (MEs) have been developed as active vehicles for sunscreens being physical sunscreens on their own.The aim of this study is to incorporate Benzophenone-3 (BZ-3), a chemical sunscreening agent into MEs resulting in a synergistic effect on its protective characteristics.
Methods: Screening of BZ-3 in different oils, surfactants and cosurfactants available for topical delivery was carried out. A full factorial study design (3.22) was adopted to study the effect of three independent variables namely;BZ-3, oil, and S/CoSmix(1:1) concentrations on the in-vitro SPF value of the prepared ME gel formulae.
Results: Formulae having SPF>30 were further evaluated regarding in-vitro permeation test. Finally, an in vitro microbiological assay was adopted to compare the survival percent of E.coli against UV exposure. Formula F11IPM ME gel consisting of 3% BZ-3 and 10% Isopropyl myristate as oil together with 60% w/w Tween80/Cremophore RH40 mix (1:1)as surfactant and cosurfactant respectively was chosen as the optimum formula having an in vitro SPF of 33.15±0.91,lowest permeation of 192±16.13µg/cm2 after eight hours and microbiological UV blocking activity of 88±5.84%which is not significantly different from the standard Spectra Ban plus (SPF=30) having a survival percent of 80±3.04%.
Conclusion: This study illustrated the potential use of microemulsified BZ-3 delivery system to improve the SPF of BZ-3
