ethylene oxide (環氧乙烷)

ethylene oxide
環氧乙烷
ethylene oxide (環氧乙烷)
環氧乙烷 (ethylene oxide)

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Toxicological Profile for Ethylene Oxide Draft for Public Comment
September 2020

At higher concentrations (300 and 400 ppm), blood ethylene oxide levels increased sublinearly and continued to increase during the 4-hour exposure. The sublinear increase in blood levels correlated with tissue glutathione depletion.
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In mice and rats, the glutathione transferase pathway is predicted to dominate; however, depletion of the glutathione will limit the capacity for conjugation at concentrations exceeding 100 ppm in the mouse and 200 ppm in the rat. T
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The model predicts that, over a range of exposures (20–500 ppm for 4 hours), the hydrolysis pathway will dominate metabolism in the human relative to the glutathione transferase pathway (EH/GST ratio: 60/20). In mice and rats, the glutathione transferase pathway is predicted to dominate; however, depletion of the glutathione will limit the capacity for conjugation at concentrations exceeding 200 ppm in the mouse. The EH/GST ratio was relatively constant (30:60) in the rat.
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3.1.6 Animal-to-Human Extrapolations
The disposition and metabolism of inhaled ethylene oxide is species dependent. Species differences exist regarding the relative contribution of the metabolic pathways discussed in Section 3.1.3 (the nonenzymatic hydrolysis pathway and the glutathione conjugation pathway) (Fennell and Brown 2001). Although ethylene oxide exposure concentrations <200 ppm are predicted to result in similar blood levels among rats, mice, and humans, higher exposure concentrations would result in higher blood levels in mice compared to rats and humans. The higher blood levels in mice are likely the result of glutathione depletion. Interspecies extrapolation would need to account for species differences in metabolic pathways, species-specific contribution of exposure concentration, and the identity of the toxicant or toxicants (ethylene oxide itself and/or its metabolite[s]) responsible for a particular toxic effect.
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Toxicological Profile for Ethylene Oxide Draft for Public Comment; September 2020
Source or References (資訊來源或是參考資訊):
https://www.atsdr.cdc.gov/toxprofiles/tp137.pdf
Info cited on 2021-12-11-WD6 (資訊引用於 中華民國110年西元2021年12月11日) by 湯偉晉 (WeiJin Tang)
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