Lipid peroxidation processes photoinduced by titanium dioxide in emulsion systems, representative of sunscreen formulations

摘要

This article studies the peroxidation of linoleic acid and of porcine skin lipids on ultraviolet B (UVB) irradiation, in the presence of various TiO_2 specimens used as inorganic sunscreen pigments in different emulsion systems. It was found that different TiO_2 specimens induce quite variable lipid peroxidation in the same emulsion system, which suggests that the different coatings widely differ in their effectiveness to lower the photocatalytic activity of TiO_2. However, it was also found that the extent of lipid peroxidation caused by the same TiO_2 pigment in different emulsions was even more variable than the effects of different pigments in the same system. This finding might imply that the choice of the formulation components different from TiO_2 could be of paramount importance as far as the potential skin damage induced by the photocatalytic activity of TiO_2 is concerned.