UV protection afforded by gel-trapped TiO2 particles

Abstract

We have developed a technology to incorporate micronized titanium dioxide (TiO₂), together with antioxidants, in particles of a UV-visible transparent polymer gel. These particles are coated with silica to avoid clustering and the size of the micronized TiO₂ reduces the back scattering of white light. gel-trapped TiO₂ minimizes the oxidative stress exerted by UV radiation, increases the photo-stability of some accompanying ingredients, such as avobenzone. The size of the particles is in the micrometre range. This favors their permanence on the top of the stratum corneum. Gel-trapped TiO₂-based sunscreens provide a larger SPF and two-fold larger UVA protection than equal-composition sunscreens that contain larger amounts of untrapped TiO₂.