Authors: A. Duggan and G. Wakefield
Affilation: Oxonica Materials Ltd, United Kingdom
Pages: 195 - 198
Keywords: sunscreen, photostability, titanium oxide, manganese, UVA
Conventional sunscreen formulations typically contain, in addition to organic UV absorbers, inorganic nanoparticles such as titanium oxide or zinc oxide. Titanium oxide nanoparticles have significant drawbacks due to a high photoactivity which results in degradation of other organic formulation components and loss of efficacy during topical use. This effect is particularly evident in loss of UVA protection. Doping a low level of manganese ions into the titanium oxide nanoparticle lattice results in an almost total quenching of photoactivity, an increase in intrinsic UVA absorption, and significant free radical scavenging activity. As a result of this, sunscreen formulations containing TiO2:Mn nanoparticle based formulations significantly outperform commercially available sunscreens over extended exposure to simulated solar radiation, resulting in high protection, UVA stable performance for all day UV protection.