Photoprotective Cosmetic Emulsions Based on Brazilian Smectite Clays

Abstract

Photoprotective cosmetic emulsions have gained significant attention in the cosmetic industry due to their ability to protect against harmful ultraviolet radiation (UV). In this work, photoprotective cosmetic emulsions were prepared by adding 5% natural (Branca and Verde Inferior) and commercial (Brasgel and Cloisite) Brazilian clays to different photoprotective emulsions with and without UVA and UVB chemical filters (EB, EB1 and EB2). All clays were benefited (crushed, milled and sieved) and characterized (X ray fluorescence and X ray diffraction). Additionally, a thermal treatment (120 °C by 24 h) was accomplished in the natural clays, aimed at decontamination. The emulsions were characterized for their organoleptic properties, centrifugation test, viscous behavior, pH values and in vitro sun protection factor (SPF). The cosmetic emulsions prepared without any addition of UV chemical filters presented the lowest in vitro and UVB absorption values because the clays used (Cloisite and Branca) did not have the potential to absorb UV radiation. Although some of the cosmetic emulsions prepared from EB1 and EB2 photoprotective emulsions presented phase separation, all of them presented in vitro SPF values according to the Brazilian standard (above 6), indicating that they have the potential to be used in the cosmetic industry.