Poly[oxy(methyl-1,2-ethanediyl)], α,α'-(2,2-dimethyl-1,3-propanediyl)bis[ω-hydroxy-]

Endpoint summary

Description of key information

No specific studies are available however based on physicochemical data, toxicity data and theoretical assessment, the basic toxicokinetics of Reaction products of 2,2-dimethylpropane-1,3-diol and methyloxirane can be adequately characterised. The substance is likely to be rapidly and extensively absorbed following oral and inhalation exposure, absorption following dermal exposure is likely to be less extensive. Rapid and extensive distribution is predicted. Extensive hepatic metabolism and urinary excretion of metabolites is likely to limit systemic exposure and no bioaccumulation is predicted.

Key value for chemical safety assessment

Bioaccumulation potential:

no bioaccumulation potential

Absorption rate - oral (%):

50

Absorption rate - dermal (%):

50

Absorption rate - inhalation (%):

100

Additional information

No specific studies are required. According to Column 1 of Annex VIII of the REACH regulation, assessment of the toxicokinetic behaviour of the substance (to the extent that can be derived from the relevant available information) is required and this is provided. An adequate assessment of the basic toxicokinetics of the substance can be made from the existing toxicity data and theoretical considerations, without the need for specific testing.

Absorption

Poly[oxy(methyl-1,2-ethanediyl)], α,α'-(2,2-dimethyl-1,3-propanediyl)bis[ω-hydroxy- is a variable molecular weight oligomer. Oral absorption is likely for the lower molecular weight oligomers (n=1, n=2) based on the moderate log Pow value and very high water solubility. Oral absorption is likely to decrease with increasing molecular weight, and is therefore likely to be less extensive for the higher molecular weight oligomers and unlikely for the highest molecular weight oligomers. Bioavailability is predicted for the low molecular weight oligomers but not for the highest molecular weight oligomers, based on Lipinski’s Rule of Five (OECD QSAR Toolbox). No oral toxicity data are available forPoly[oxy(methyl-1,2-ethanediyl)], α,α'-(2,2-dimethyl-1,3-propanediyl)bis[ω-hydroxy. A default assumption of 50% oral absorption may be made for the purposes of risk assessment, according to REACH Guidance.

The dermal absorption ofPoly[oxy(methyl-1,2-ethanediyl)], α,α'-(2,2-dimethyl-1,3-propanediyl)bis[ω-hydroxy- is likely to be less extensive than its oral absorption; a degree of dermal absorption is likely but this will be more extensive for the lower molecular weight oligomers (n=1, n=2) and may be low for the higher molecular weight oligomers. The very low vapour pressure ofPoly[oxy(methyl-1,2-ethanediyl)], α,α'-(2,2-dimethyl-1,3-propanediyl)bis[ω-hydroxy-means that any substance coming into contact with the skin is unlikely to be lost through volatilisation. Dermal absorption is therefore predicted, but is likely to be less rapid and extensive than oral absorption. Surfactant properties are predicted forPoly[oxy(methyl-1,2-ethanediyl)], α,α'-(2,2-dimethyl-1,3-propanediyl)bis[ω-hydroxy-(OECD QSAR Toolbox), which may act to increase dermal absorption through the disruption of protein structure. In the absence of any specific data, a default assumption of 50% dermal absorption may be made for the purposes of risk assessment, according to REACH Guidance and on the basis that dermal absorption will not exceed oral absorption.

Poly[oxy(methyl-1,2-ethanediyl)], α,α'-(2,2-dimethyl-1,3-propanediyl)bis[ω-hydroxy- is of very low volatility, therefore inhalation exposure is not predicted unless the substance is used in situations in which liquid aerosols may be generated (e.g. by spraying). If inhalation exposure were to occur, absorption is potentially extensive. A default assumption of 100% inhalation absorption may be made, if required, for the purposes of risk assessment.

Distribution

Based on its high water solubility, the systemic distribution of absorbed Poly[oxy(methyl-1,2-ethanediyl)], α,α'-(2,2-dimethyl-1,3-propanediyl)bis[ω-hydroxy- is likely to be rapid and extensive following oral, dermal or inhalation exposure.

Metabolism

OECD QSAR Toolbox predicts a total of 66 hepatic metabolites generated through ether hydrolysis and sequential oxidation.

Excretion

The high water solubility and low molecular weight ofPoly[oxy(methyl-1,2-ethanediyl)], α,α'-(2,2-dimethyl-1,3-propanediyl)bis[ω-hydroxy- and its metabolites indicate rapid urinary excretion. The predicted metabolism of the substance and its log Pow value indicate that bioaccumulation is unlikely.