Protetor solar formulado com a substituição do dióxido de titânio (TiO2) por argilas.

Abstract

The potential of several clays, including industrialized sodium bentonite and polycationic natural bentonites from deposits located in the Paraiban municipalities of Boa Vista, Cubati, Sossego and Olivedos, for protection against ultraviolet (UV) radiation in the 250-400 nm range was examined. Nine clays were initially characterized by X-ray fluorescence (EDX) and X-ray diffraction (XRD). Based on titanium dioxide (TiO2), zinc oxide (ZnO) and ferric oxide (Fe2O3) contents, three clays were selected for the preparation of sunscreen formulations. The formulations of sunscreens with clays, prepared in a handling pharmacy in the city of Campina Grande/PB, were characterized by ultraviolet spectrophotometry (UV-Vis) and the values of sun protection factor (SPF) determined. The clays blocked the UV radiation and the Fe2O3 content was not determinant in the UV radiation protection properties. The color, odor, hydrogen potential and stability of sunscreen cream were not altered by the presence of clay and when applied to the skin presented excellent spreadability, with formation of transparent film. In addition to their high potential for protection against UV radiation and for controlling the proliferation of fungi and bacteria, bentonite clays are natural, abundant, inexpensive, chemically inert and have low or zero toxicity to patients, which makes them promising as an additive for sun protection creams.