In vitro evaluation of the cutaneous penetration of sprayable sunscreen emulsions with high concentrations of UV filters

Abstract

The aim of this study was to evaluate the possible penetration through human skin of organic and inorganic filters contained in sunscreen emulsions packaged in aerosol cans, using an in vitro method. Experiments were carried out on two different types of emulsion: W/Si and W/O. This study was conducted using static diffusion cells (Franz cells). The determination of organic UV filters [Methylene Bis Benzotriazolyl Tetramethylbutylphenol (MBBT); Bis-Ethylhexyloxyphenol Methoxyphenyl Triazine (BEMT); Diethylamino Hydroxybenzoyl Hexyl Benzoate (DHHB); Ethylhexyl Methoxycinnamate (EMC); and 2-Ethylhexyl Dimethyl PABA (ED-PABA)] was performed by High Performance Liquid Chromatography (HPLC). Therefore, it was important to develop a single analytical method for the quantification of the five organic filters with the aim of facilitating the experiment. The determination of inorganic filters [titanium dioxide (TiO(2)) and zinc oxide (ZnO)] was performed using an emission spectrometric analysis method (ICP-OES). The HPLC and ICP-OES methods were validated. After a penetration test of 24 h duration, the results showed very low penetration only for two of the organic filters (maximum penetration of 1.21 microg cm(-2) h(-1) for EMC and 0.14 microg cm(-2) h(-1) for MBBT) and no penetration for the inorganic filters. Moreover, more than 50% of each sunscreen agent stayed on the surface on the skin. These results are consistent with those in the literature that presents similar experiments. This study showed that the sprayable sunscreen products developed, which contained high concentrations of UV filters, presented a low level of skin penetration.