5-ethyl-1,3-dioxane-5-methanol

Endpoint summary

Link to relevant study record(s)

Reference

Endpoint:

basic toxicokinetics, other

Data waiving:

other justification

Justification for data waiving:

other:

Description of key information

No specific studies are available. 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.

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 REACH, 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

Based on an assessment of its physicochemical properties, CTF (5 -ethyl-1,3 -dioxane-5 -methanol) is likely to be extensively absorbed following oral and inhalation exposure. Dermal absorption is demonstrated by findings in the 90 -day toxicity study. Dermal absorption is also likely but may be less extensive. The substance satisfies Lipinski's rule of 5 (OECD QSAR Toolbox). In the absence of any specific data, default assumptions of 50%, 50% and 100% absorption are made for the oral, dermal and inhalation routes respectively for the purposes or risk assessment, according to REACH Guidance (and on the basis that dermal absorption will not exceed oral absorption).

Distribution

5 -ethyl-1,3 -dioxane-5 -methanol is a water soluble small molecule and is therefore likely to be rapidly and extensively distributed in the blood following oral, dermal or inhalation exposure. Findings in the 90 -day rat study demonstrate distribution of CTF to the liver, and also indicate the distribution of CTF (and/or its metabolites) to the systemic circulation and kidneys.

 

Metabolism

5 -ethyl-1,3 -dioxane-5 -methanol can be predicted to be extensively metabolised by a combination of hydrolytic and oxidative reactions. The OECD QSAR Toolbox predicts a total of 44 low molecular weight hepatic metabolites. Findings of increased liver weight in the 90 -day rat study are consistent with the extensive hepatic metabolism of CTF.

Excretion

Rapid urinary excretion of the low molecular weight and water-soluble metabolites of 5 -ethyl-1,3 -dioxane-5 -methanol is predicted; bioaccumulation is therefore unlikely. Increased kidney weights, seen in the 90 -day rat study, are consistent with the urinary excretion of CTF and/or its metabolites.