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Categories

Categories

Category name:
3-MPA family, simple esters

Justifications and discussions

Category definition:
3-Mercaptopropionic acid, and its esters
Category description:
This category includes 3-MPA and esters of 3-MPA with mono-alcohols differing in C-chain length (C1 – C18) and degree of branching.
Category rationale:
This category includes 3-MPA and esters of 3-MPA with mono-alcohols differing in C-chain length (C1 – C18) and degree of branching. BuMP and ODMP contain a linear alcohol side chain, whereas EHMP is manufactured from 2-ethylhexanol, and iOMP and iC13MP contain branched site chains with overall a low degree of branching (mostly methyl-branches).
3-MPA as free acid is included in this category, since it is formed by ester hydrolysis and is therefore the primary common metabolite in this category.
The category members follow structurally related trends in physical chemical properties (water solubility, log Kow, and vapour pressure). The available acute oral toxicity studies also revealed a trend towards less toxicity with increasing carbon chain length. All members share a common chemical reactivity, metabolism pathways and biological properties that enable interpolation and read across between category members for systemic toxicity endpoints.
Esters with poly-alcohols are assigned to a separate category since they contain more than one free sulfhydryl function.