ABSTRACT
Several parameters should be assessed during the formulation phase in order to provide safe and efficient sunscreens with a high cosmetic quality. Product safety is guaranteed by reduced adverse reactions mainly caused by fragrances, preservatives, emulsifiers, and UV-filters. Of the UV radiation that reaches the Earth, 90-99" is UVA and only 1-10" is UVB. UVC is filtered by the ozone layer and does not reach the Earth. The first commercial sunscreen, an emulsion containing benzyl salicylate and benzyl cinnamate, became available in the US in 1928. While there are more chemical than physical UV-filters on the market, the use of inorganic UV-filters has many advantages when compared to the chemical UV-filters, such as enhancement of the protection level in the longer UVA range, photostability of the molecules, and a low photoallergic potential. It is well accepted that the use of adequate broad-spectrum UV-filters prevents photoaging and skin cancer.
