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Proposal of GHS sub-categorization criteria for LLNA: BrdU-ELISA (OECD TG442B)
Yosuke Maeda1, Masahiro Takeyoshi2
1Chemicals Assessment and Research Center, Chemicals Evaluation and Research Institute (CERI), 1600, Shimotakano, Sugito-machi, Kitakatsushika-gun, Saitama, 3450043, Japan; The United Graduate School of Veterinary Science, Yamaguchi University, 1677-1 Yoshida, Yamaguchi-shi, Yamaguchi, 7538511, Japan.
Abstract:
The Globally Harmonized System of Classification and Labelling of Chemicals (GHS) is a hazard classification and communication system for providing information on the safe handling of chemicals worldwide. While the GHS provides sub-categorization criteria for sensitizers when using the guinea pig maximization test/Buehler test (OECD TG406) and the standard radioisotopic LLNA (OECD TG429), the sub-categorization criteria for LLNA: BrdU-ELISA (OECD TG442B) are not currently provided. In this study, we re-analyzed the existing data of 32 sensitizers classified in the 1A or 1B categories of the GHS, and attempted to determine optimal criteria for GHS sub-categorization using LLNA: BrdU-ELISA. Consequently, the optimal criterion for the GHS sub-categorization was determined to be 6% when using EC1.6, showing the correct outcomes (%) for GHS 1A and GHS 1B category chemicals were 92.3 and 84.2 for all 32 chemicals, respectively. When excluding 2-mercaptobenzothiazole which may cause strain specific low response in this assay system, the correct outcomes (%) for GHS 1A chemicals was 100. Further work would be necessary, but the GHS sub-categorization criteria proposed in this study might be promising when using LLNA: BrdU-ELISA to provide information on the skin sensitization potency category of chemicals.
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