Registration Dossier

Administrative data

Link to relevant study record(s)

Reference
Endpoint:
basic toxicokinetics in vitro / ex vivo
Data waiving:
study technically not feasible
Justification for data waiving:
other:

Description of key information

REACH_data waiving | Basic toxicokinetics

Key value for chemical safety assessment

Additional information

Ethanol, 2,2'-oxybis-, reaction products with 3-(triethoxysilyl)-1-propanamine (CAS 152261-43-3) is a complex reaction mixture (UVCB) of 3-aminopropyltriethoxysilane (CAS 919-30-2) and diethylene glycol (CAS111-46-6). Diethylene glycol is the main component besides smaller amounts of ethanol (CAS 64-17-5). No free 3-aminopropyltriethoxysilane is detectable, because it is covalently bound to the oligomeric structures of the reaction product.

Ethanol, 2,2'-oxybis-, reaction products with 3-(triethoxysilyl)-1-propanamine is unstable upon contact with moisture. lt undergoes further condensation reactions that form highly polymerized poly silicic acids while liberating the diethylene glycol, that was initially bound to the oligomeric structures. The underlying chemistry is commonly known as sol-gel reaction. The poly silicic acid moieties are not stable and prone to further condensation generatingwaterinsoluble, resinous polymers. The molecular weight of the resulting polymers is predicted to be over 1000. These polymers are stable and not bioavailable.

Due to the reactivity of Ethanol, 2,2'-oxybis-, reaction products with 3-(triethoxysilyl)-1-propanamine toxicokinetic assessment cannot be performed.

Because 3-aminopropyltriethoxysilane is completely consumed into polymer matrix the toxicological profile of Ethanol, 2,2'-oxybis-, reaction products with 3-(triethoxysilyl)-1-propanamine will be mainly determined by diethylene glycol and to a lesser extent by ethanol.

Diethylene glycol is almost completely absorbed via oral route. Dermal bioavailability of diethylene glycol was estimated to be 10%. The main metabolic pathway for metabolism of diethylene glycol is oxidation via alcohol dehydrogenases and aldehyde dehydrogenases. The main metabolite found was 2-hydroxyethoxyacetic acid besides oxalic acid and other acid metabolites. Acid metabolites of diethylene glycol are eliminated in urine and may also be metabolized to carbon dioxide and eliminated in exhaled breath (see REACH registration dossier, ECHA dissemination site; OECD SIDS Dossier, diethylene glycol, 2007).  

Ethanol is absorbed by all application routes. It is mainly distributed in the body in aqueous compartments. More than 90% of the resorbed dose is metabolized in the liver, with the remaining quantity being eliminated unchanged via kidney or exhaled. Ethanol is metabolized in the liver by oxidation to acetaldehyde and acetic acid. The acetic acid enters intermediary metabolism or is degraded to water and CO2(see REACH registration dossier, ECHA dissemination site).