Application of In Vitro Skin Allergy-Amino Acid Derivative Reactivity Assay in Preliminary Screening of Sensitization of Sunscreens

The sensitization of 20 chemical sunscreens was evaluated using amino acid derivative reactivity assay (ADRA). Cysteine derivative N-2-(1-naphthyl) acetyl-L-cysteine (NAC) and lysine derivative α-N-2-(1-naphthyl) acetyl-L-lysine (NAL) were used to mimic skin proteins, which reacted with chemical sunscreens. The amino acid derivative depletion percentage of 20 chemical sunscreens were determined by high performance liquid chromatography, and then their skin sensitization were predicted. The feasibility of ADRA method was judged by comparing the consistency of ADRA prediction results with the compound evaluation reports produced by European Scientific Committee on Consumer Safety (SCCS). It was shown that 19 chemical sunscreens such as 3-benzylidene camphor were predicted to be negative, and benzophenone-3 was predicted to be positive. ADRA could be used as an alternative in vitro method for animal experiments to predict and screen the skin sensitization of compounds simply and quickly.