Ethyl 2-methyl-1,3-dioxolane-2-acetate

Endpoint summary

Description of key information

The substance is a colourless to pale yellow liquid whose molecular weight is 174.19 g/L. Its water solubility is 124.8 g/L and Log POW is 0.8. The substance does not contain any ionisable group and it is hydrolitically stable. These physical-chemical properties, as well as results from toxicology and ecotoxicology studies, have been taken into account for determining a toxicokinetic profile.

Key value for chemical safety assessment

Bioaccumulation potential:

low bioaccumulation potential

Absorption rate - oral (%):

100

Absorption rate - dermal (%):

25

Absorption rate - inhalation (%):

100

Additional information

Absorption

Oral absorption: because of the low molecular weight (174.19 g/mol), good water solubility (124.8 g/L) and moderate Log P_OW(0.8) it is likely that the substance may pass through aqueous pores (bulk passage of water) or be carried through the epithelial barrier by diffusion. In a fully compliant OECD 422 study no signs of systemic toxicity up to an including the limit dose of 1000 mg/kg/day were observed, and this may be due to rapid elimination and/or low intrinsic toxicity (no toxicity was observed in aquatic ecotoxicity tests at limit concentrations). On this basis 100% oral absorption will be used for risk assessment purposes.

Inhalation absorption: the good water solubility suggests that vapour of the substance could be retained within the mucus however the small molecular weight as well as the moderate Log P_OWwould infer absorption by passive diffusion across the respiratory tract epithelium, similarly with what is expected to occur following oral administration. In the absence of specific data, inhalation absorption is assumed to be complete (100%) for risk assessment purposes.

Dermal absorption: the physical state and low molecular weight would favour dermal uptake however, because of the good water solubility and moderate Log P_OW it is considered that the substance may be too hydrophilic to cross the stratum corneum. On this basis a value of 25% dermal absorption will be used for risk assessment purposes, in accordance with principles adopted in the EFSA guidance on estimating dermal absorption of pesticide active substances (EFSA, 2012).

 

Distribution

The substance is relatively small and has good water solubility therefore a wide distribution within the body can be expected. Given the moderate Log P_OWvalue, potential for bioaccumulation is low and this is supported by the results of a fully compliant OECD 422 study in which no signs of toxicity were observed up to and including the limit dose of 1000 mg/kg/day.

 

Metabolism

No substantial metabolism is expected. The material was determined to be not readily biodegradable and is hydrolytically stable under the entire range of pH values (4, 7 or 9) which can be encountered within the body, with half-lives longer than one year at pH 4 and 7, and of more than 11 days at pH 9.Based on the chemical structure of the test material, changes at the ester functional group could produce 1,3-dioxolane-2-acetic acid, 2-methyl and ethanol.

 

Excretion

Given the low molecular weight and good water solubility the substance can be expected to be rapidly absorbed and excreted into the urine, either unchanged by passive diffusion or as conjugates.