Related Articles Analytical studies on photochemical behavior of phototoxic substances; effect of detergent additives on singlet oxygen generation. Pharm Res. 2008 Apr;25(4):861-8 Authors: Onoue S, Yamauchi Y, Kojima T, Igarashi N, Tsuda Y PURPOSE: Monitoring of reactive oxygen species (ROS) generation from photoirradiated compounds would be effective for the prediction of the phototoxic potential. The aim of this investigation was to clarify the possible role of biomimetic vehicle systems on the photochemical properties of phototoxic compounds, focusing on the singlet oxygen generation. MATERIALS AND METHODS: Nine phototoxic and one non-phototoxic compounds (200 microM), dissolved in Tween 20, sodium laurate, or sodium dodecyl sulfate (SDS) micellar solution, were exposed to UVA/B light (250 W/m2), and singlet oxygen generation was monitored by RNO bleaching methodology. Photochemical properties of photosensitizers were also evaluated by UV measurement, and the interaction of photosensitizers with surfactant micelles was assessed by Z-potential and NMR spectroscopic analyses. RESULTS: All phototoxic compounds tended to generate singlet oxygen under light exposure in the all micellar solutions tested. There appeared to be some differences in photoreactivity of both cationic and anionic photosensitizers among the micelles tested, whereas ROS data on anthracene, dissolved in three micellar solutions, were found to be quite similar. Phot ...