Enzymatic reactive oxygen species assay to evaluate phototoxic risk of metabolites.

Enzymatic reactive oxygen species assay to evaluate phototoxic risk of metabolites. Toxicol Lett. 2017 Jul 08;: Authors: Kato M, Ohtake H, Sato H, Seto Y, Onoue S Abstract The present study aimed to verify the feasibility of an enzymatic reactive oxygen species (eROS) assay to evaluate the phototoxic risk of compounds after their metabolization. The eROS assay was designed based on the combined use of an in vitro drug metabolism system and a ROS assay. The incubation time of compounds with human hepatic S9 fractions was optimized with the use of fenofibrate (FF), a typical phototoxicant with metabolite-related phototoxicity, and the reproducibility and robustness of the eROS assay were examined using FF. The eROS assay was applied to 12 phototoxic compounds, including 7 phototoxicants with metabolite-related phototoxicity, to clarify the assay performance. According to the eROS data on singlet oxygen generation from FF and metabolic conversion profiles of FF and fenofibric acid, the incubation time of chemicals with human hepatic S9-mix was determined to be 4min. The singlet oxygen-based evaluation system in the eROS assay was found to be acceptable as a high-throughput assay because of its favorable intra-/inter-day reproducibility (coefficient of variation: ca. 8%) and robustness (Z'-factor: 0.23). Singlet oxygen data on phototoxicants with phototoxic metabolites tended to exceed 120% of control, suggesting the feasibility of the e...
Source: Toxicology Letters - Category: Toxicology Authors: Tags: Toxicol Lett Source Type: research