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

Synopsis 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 (TiO2) 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 μg cm−2 h−1 for EMC and 0.14 μg 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. Resume Le but de cette etude etait d’evaluer le potentiel de penetration cutanee de filtres organiques et inorganiques contenus dans des emulsions solaires conditionnees sous forme d’aerosol en utilisant une methode in vitro. Pour cela, des methodes analytiques ont duetre mises au point. Ces experiences ont ete realisees sur deux types d’emulsion (E/H et E/Si). Cette etude a ete realisee en utilisant des cellules de diffusion statiques (Cellules de Franz). La determination des filtres UV organiques (Methylene Bis Benzotriazolyl Tetramethylbutylphenol (MBBT); Bis-Ethylhexyloxyphenol Methoxyphenyl Triazine (BEMT); Diethylamino Hydroxybenzoyl Hexyl Benzoate (DHHB); Ethylhexyl Methoxycinnamate (EMC); 2-Ethylhexyl Dimethyl PABA (ED-PABA)) a ete effectuee a 1’aide de la Chromatographie Liquide Haute Performance (CLHP). II etait done important de developper une methode unique pour la quantification des cinq filtres organiques en presence dans le but de faciliter 1’etude. La determination des filtres inorganiques (dioxyde de titane (TiO2) et oxyde de zinc (ZnO)) a ete accomplie en utilisant une methode d’emission spectrometrique (ICP-OES). Ces deux methodes analytiques ont ete validees. Apres une duree de test de 24 h, les resultats ont montre une tres faible penetration pour deux des filtres organiques (Maximum 1.21 μg/cm2/h pour 1’EMC et 0.14 μg/cm2/h pour le MBBT) et pas de penetration pour les filtres inorganiques. De plus, plus de 50% des filtres UV restent a la surface de la peau. Les resultats obtenus corroborent ceux presentes dans la litterature. Des produits solaires sprayable contenant de fortes concentrations en filtres UV et possedant un faible taux de passage cutane ont ete developpes.