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Description of key information

Short description of key information on bioaccumulation potential result: 
Di-2-EHTDG is predicted to be bioavailable via the oral route but is very poorly absorbed via skin.
Di-2-EHTDG is expected to undergo stepwise hydrolysis of the ester bonds yielding thiodiglycolic acid (TDGA; CAS: 123-93-3) and 2-ethyl-1-hexanol (2-EH; CAS: 104-76-7). Both substances are very polar and thus subject to renal elimination. Tissue accumulation can be excluded.

Key value for chemical safety assessment

Bioaccumulation potential:
no bioaccumulation potential
Absorption rate - oral (%):
100
Absorption rate - dermal (%):
0.05
Absorption rate - inhalation (%):
0.05

Additional information

Absorption

Oral absorption of Di-2-EHTDG is predicted to be high. The Danish EPA (% G.I. abs. for 1 mg dose) predicts an oral absorption of 100% following a dose of 1 mg.

The EpiSuite DermWin v2.02 program predicts a very low dermal absorption of 0.00003 mg/cm²/event.

The inhalative absorption can be neglected due to the very low vapour pressure of the substance.

Distribution

The substance will be hydrolysed; the hydrolysis products are water soluble and are predicted to have no accumulation potential. They are expected to enter the urine shortly after systemic absorption.

Metabolism

Di-2-EHTDG will undergo enzymatic and non-enzymatic ester hydrolysis. This is a stepwise process and mixed hydrolysis and oxidation products are likely to occur at least as intermediate metabolites.

The resulting molecules, TDGA and 2-EH, are soluble in water. Both substances can be further oxidised [R2S to R2S(=O)2; -CH2OH to -COOH]. Carboxylic acids can be subject to glucuronidation (mediated by UGT isozymes) prior to urinary excretion.

Excretion

The hydrolysis products of Di-2-EHTDG as well as the oxidised metabolites are soluble in water (TDGA: 317 g/L; 2-EH: 1 g/L, 2-ethylhexanoic acid: 1.1 g/L) and will be excreted rapidly via urine, either as such or as conjugates with glucuronic acid. Significant faecal excretion is not expected.