Prodotti solari: Fotoprotezione e fotostabilità

Ultraviolet (UV) radiation is an etiologic cause for non-melanoma skin cancer (basalcell carcinoma and squamouscell carcinoma) and malignant melanoma, but the spectral range promoting the tumor induction is still to be explained. It follows that it is mandatory the complete photoprotection from sunscreens towards the whole UV range. In the European Union, sunscreens are tested on their effectiveness by means of 4 indicators: SPF (Sun Protection Factor), UVA-PF (Protection Factor), SPF/PF-UVA ratio, and critical wave length. However, SPF can confirm that sunscreen products protect us from sunburn under good condition of use. In order to achieve a whole protection, instead, it is also interesting to calculate other indicators to assess protection against non-melanoma skin cancers and to quantify the effectiveness of the product against UVA1 and UVA2. Photostability of sunscreens represents a further significant problem concerning photoprotection. It has been clearly demonstrated that not all UVA and UVB absorbers are sufficiently photostable. Within UV exposure, in fact, some of them may change spectral performance. High SPF value implies the long-lasting photoprotection, but this is only guaranteed when UV filters remain stable throughout the entire period of sun exposure. Thus, the production of photostable products is extremely important. But, most sunscreens on the market do not have a photostability label. Therefore, there is a need for a global uniform claim on UV photoprotection.