title: Phototoxicity Evaluation of Pharmaceutical Substances with a Reactive Oxygen Species Assay Using Ultraviolet A.
abstract: With ultraviolet and visible light exposure, some pharmaceutical substances applied systemically or topically may cause phototoxic skin irritation. The major factor in phototoxicity is the generation of reactive oxygen species (ROS) such as singlet oxygen and superoxide anion that cause oxidative damage to DNA, lipids and proteins. Thus, measuring the generation of ROS can predict the phototoxic potential of a given substance indirectly. For this reason, a standard ROS assay (ROS assay) was developed and validated and provides an alternative method for phototoxicity evaluation. However, negative substances are over-predicted by the assay. Except for ultraviolet A (UVA), other UV ranges are not a major factor in causing phototoxicity and may lead to incorrect labeling of some non-phototoxic substances as being phototoxic in the ROS assay when using a solar simulator. A UVA stimulator is also widely used to evaluate phototoxicity in various test substances. Consequently, we identified the applicability of a UVA simulator to the ROS assay for photoreactivity. In this study, we tested 60 pharmaceutical substances including 50 phototoxins and 10 non-phototoxins to predict their phototoxic potential via the ROS assay with a UVA simulator. Following the ROS protocol, all test substances were dissolved in dimethyl sulfoxide or sodium phosphate buffer. The final concentration of the test solutions in the reaction mixture was 20 to 200 μM. The exposure was with 2.0~2.2 mW/cm2irradiance and optimization for a relevant dose of UVA was performed. The generation of ROS was compared before and after UVA exposure and was measured by a microplate spectrophotometer. Sensitivity and specificity values were 85.7% and 100.0% respectively, and the accuracy was 88.1%. From this analysis, the ROS assay with a UVA simulator is suitable for testing the photoreactivity and estimating the phototoxic potential of various test pharmaceutical substances.
authors.affiliation: Toxicological Screening and Testing Division, National Institute of Food and Drug Safety Evaluation, Ministry of Food and Drug Safety, Cheongju, Korea.
authors.forename: Yong Sun
authors.initials: YS
authors.lastname: Lee
authors.affiliation: Toxicological Screening and Testing Division, National Institute of Food and Drug Safety Evaluation, Ministry of Food and Drug Safety, Cheongju, Korea.
authors.forename: Jung-Sun
authors.initials: JS
authors.lastname: Yi
authors.affiliation: Herbal Medicinal Products Division, National Institute of Food and Drug Safety Evaluation, Ministry of Food and Drug Safety, Cheongju, Korea.
authors.forename: Hye Rim
authors.initials: HR
authors.lastname: Lim
authors.affiliation: Toxicological Screening and Testing Division, National Institute of Food and Drug Safety Evaluation, Ministry of Food and Drug Safety, Cheongju, Korea.
authors.forename: Tae Sung
authors.initials: TS
authors.lastname: Kim
authors.affiliation: Toxicological Screening and Testing Division, National Institute of Food and Drug Safety Evaluation, Ministry of Food and Drug Safety, Cheongju, Korea.
authors.forename: Il Young
authors.initials: IY
authors.lastname: Ahn
authors.affiliation: Toxicological Screening and Testing Division, National Institute of Food and Drug Safety Evaluation, Ministry of Food and Drug Safety, Cheongju, Korea.
authors.forename: Kyungyuk
authors.initials: K
authors.lastname: Ko
authors.affiliation: Toxicological Screening and Testing Division, National Institute of Food and Drug Safety Evaluation, Ministry of Food and Drug Safety, Cheongju, Korea.
authors.forename: JooHwan
authors.initials: J
authors.lastname: Kim
authors.affiliation: Toxicological Evaluation and Research Department, National Institute of Food and Drug Safety Evaluation, Ministry of Food and Drug Safety, Cheongju, Korea.
authors.forename: Hye-Kyung
authors.initials: HK
authors.lastname: Park
authors.affiliation: Toxicological Research Division, National Institute of Food and Drug Safety Evaluation, Ministry of Food and Drug Safety, Cheongju, Korea.
authors.forename: Soo Jung
authors.initials: SJ
authors.lastname: Sohn
authors.affiliation: Toxicological Screening and Testing Division, National Institute of Food and Drug Safety Evaluation, Ministry of Food and Drug Safety, Cheongju, Korea.
authors.forename: Jong Kwon
authors.initials: JK
authors.lastname: Lee
keywords: Alternative testing method; Photoreactivity; Photosafety screening; Phototoxicity; Reactive oxygen species; Ultraviolet A