title: Assessment of the photo-degradation of UV-filters and radical-induced peroxidation in cosmetic sunscreen formulations.
abstract: Photo-instability of common UV-filters is a well documented phenomenon. This study develops a method for concomitant measurement of photostability and photo-induced ROS generation in cosmetic formulations. Oil-in-water formulations containing three common UV filters (OMC, BMDBM, EHT), individually or combined, were further supplemented with phosphatidylcholine and exposed to UVA. All filters show spectral decrease after UVA exposure. OMC and EHT do not induce significant lipid-peroxidation (as measured by TBARS production) while BMDBM does. In the latter case, this is reduced when BMDBM is combined with OMC but not with EHT. Neither OMC nor EHT stabilize BMDBM with respect to loss of absorbance. ROS-generation assessed via TBARS formation was supported by EPR experiments. The UV-induced changes in UV-filter performance, as monitored in the model formulations and in commercial sunscreens, demonstrate that this is a simple and effective method for stability assessment of sunscreen filters under conditions of use.
authors.affiliation: Dipartimento di Biochimica, Biologia e Genetica, Università Politecnica delle Marche, I-60131 Ancona, Italy. e.damiani@univpm.it
authors.forename: Elisabetta
authors.initials: E
authors.lastname: Damiani
authors.forename: Paola
authors.initials: P
authors.lastname: Astolfi
authors.forename: Jochen
authors.initials: J
authors.lastname: Giesinger
authors.forename: Thomas
authors.initials: T
authors.lastname: Ehlis
authors.forename: Bernd
authors.initials: B
authors.lastname: Herzog
authors.forename: Lucedio
authors.initials: L
authors.lastname: Greci
authors.forename: Werner
authors.initials: W
authors.lastname: Baschong
mesh_terms: D019411:Clinical Laboratory Techniques; D003358:Cosmetics / Q000032:analysis / Q000528:radiation effects; D004355:Drug Stability; D004578:Electron Spin Resonance Spectroscopy; D005609:Free Radicals / Q000378:metabolism / Q000528:radiation effects; D010782:Photolysis / Q000528:radiation effects*; D017382:Reactive Oxygen Species / Q000032:analysis / Q000528:radiation effects*; D013473:Sunscreening Agents / Q000032:analysis / Q000528:radiation effects*; D017392:Thiobarbituric Acid Reactive Substances / Q000032:analysis; D014466:Ultraviolet Rays
chemical_list: D003358:Cosmetics; D005609:Free Radicals; D017382:Reactive Oxygen Species; D013473:Sunscreening Agents; D017392:Thiobarbituric Acid Reactive Substances