Characterization of the Coating Efficacy of Inorganic UV Filters by Using Electron Spin Resonance Spectroscopy

Methods of direct coating are based on a protective film of organic or inorganic material. This protective film should envelope perfectly the nano-particle to prevent direct contact with the viable cells. The characterization of UV-filters (passive ingredients) is performed by in vitro measurements like the evaluation of the Photo Stability Rate (PSR) of chemical UV-Filters and the Coating Rate Efficacy (CRE) of physical UV Filters. The efficacy for minimizing the adverse catalytic effect of physical UV filters is measured by the Radical Status Factor (RSF). All methods together establish a coherent basement which may help to design modern cosmetics with a modern architecture aimed to slow down the free radical injury and the premature aging process, meanwhile improving a sophisticated and pleasant texture.