Photo-stability and photo-sensitizing characterization of selected sunscreens' ingredients

Sunscreen products are mostly used to protect human skin from adverse effects of ultra-violet light like DNA damage, photo-aging and sunburns. Photo-stability is one of the critical requirements for an effective sunscreen. However, most commercially available sunscreen compounds exhibit photo reactions leading to formation of harmful products. The objective of the current research was to investigate the photo-chemical and photo-physical properties of few selected sunscreens formulations and also to explore photo-stability and photo-sensitizing properties of few selected organic UV filters used in the sunscreens. Photo-degradation mechanisms of the selected sunscreens ingredients were analysed using time-resolved Laser Flash Photolysis and steady-state HPLC coupled with Mass Spectrometry. Oxybenzone (OXB) was revealed to be a sufficiently stable UV filter even after 24 h of radiation exposure, whereas, Avobenzone (AVOB) and Ecamsule (ECAM) were found to be a photo-unstable sunscreen. (C) 2016 Elsevier B.V. All rights reserved.