EEC/COLIPA project on in vitro phototoxicity testing: First results obtained with a Balb/c 3T3 cell phototoxicity...

In a joint validation project eight laboratories from the European Cosmetic Industry Association (COLIPA) as well as FRAME (England) and ZEBET (Germany) are trying to develop validated in vitro methods to be incorporated into new international guidelines for acute phototoxicity testing. The first stage of the study involved selection of the most promising in vitro phototoxicity tests for further validation. 20 chemicals with known phototoxic properties (12 phototoxins, four UV-absorbing non-phototoxins and four non-UV absorbing non-phototoxins) were tested under identical conditions of UV exposure conditions (sun simulator, UVA 5 J/cm(2)) in a standardized cytotoxicity assay with Balb/c 3T3 fibroblasts (endpoint: neutral red uptake, NRU). 19 of the 20 chemicals were correctly classified by the 3T3 NRU phototoxicity test, and therefore, this simple assay for phototoxicity seems very promising and should be validated further.