Skin penetration and photoprotection of topical formulations containing benzophenone-3 solid lipid microparticles prepared by the solvent-free spray-congealing technique

摘要

Purpose: Solid-lipid microparticles loaded with high amounts of the sunscreen UV filter benzophenone-3 were prepared by spray congealing with the objective of decreasing its skin penetration and evaluate whether the sunscreen's photoprotection were impaired by the microencapsulation process. Methods: The microparticles were produced using the natural lipids carnauba wax or bees wax and three different concentrations of benzophenone-3 (30, 50 and 70%) using spray congealing technique. Results: The microparticles presented properties suitable for topical application, such as spherical morphology, high encapsulation efficiency (95.53-102.2%), average particle sizes between 28.5 and 60.0 mu m with polydispersivities from 1.2 to 2.5. In studies of in vitro skin penetration and preliminary stability, formulations of gel cream containing carnauba wax solid lipid microparticles and 70% benzophenone-3 when compared to the formulation added of bees wax solid-lipid microparticles containing 70% benzophenone-3, was stable considering the several parameters evaluated and were able to decrease the penetration of the UV filter into pig skin. Moreover, the formulations containing solid lipid microparticles with 70% benzophenone-3 increased the photoprotective capacity of benzophenone-3 under UV irradiation. Conclusion: The results show that spray-congealed microparticles are interesting solid forms to decrease the penetration solar filters in the skin without compromising their photoprotection.