Registration Dossier
Registration Dossier
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EC number: 211-659-0 | CAS number: 682-01-9
Endpoint summary
Administrative data
Description of key information
Key value for chemical safety assessment
Skin sensitisation
Endpoint conclusion
- Endpoint conclusion:
- no adverse effect observed (not sensitising)
- Additional information:
There is one negative skin sensitisation study for tetrapropyl orthosilicate, but there was no evidence of a positive control or preliminary study in the study report, therefore the study is not sufficiently reliable to be a key study. There is also a skin sensitisation study on the structurally-related substance, tetraethyl orthosilicate, which was also negative. Together these two studies form a weight-of-evidence against a sensitising potential for tetrapropyl orthosilicate.
In the absence of reliable data for tetrapropyl orthosilicate, it is considered appropriate to use an additional study on tetraethyl orthosilicate to form a weight-of-evidence for the skin sensitisation endpoint.
The registered substance and read-across substance are both moderately lipophilic substances (log Kow3.4 and 3.0, respectively) for which dermal uptake is favourable. After uptake both substances hydrolyse rapidly with half-lives of 1.6 and 2.5 hours respectively at pH 7 and 37.5°C forming propanol or ethanol and silicic acid. N-propanol is not sensitising to skin (EC, 2008), nor is ethanol (OECD, 2004), therefore read-across based on the common hydrolysis product is relevant.
Migrated from Short description of key information:
Two studies form a weight-of-evidence for skin sensitisation potential of tetrapropyl orthosilicate.
In a guinea pig maximisation study conducted using a protocol comparable to OECD 406 (with restrictions: no positive control or preliminary study) and to GLP (Dow Corning Corporation, 1984; reliability score 4) tetrapropyl orthosilicate was not sensitising to the skin of guinea pigs.
In a skin sensitisation study (Buehler test; reliability score 2) conducted to OECD 406 (with restrictions: only 10 test animals and no positive control) tetraethyl orthosilicate was not sensitising to the skin of guinea-pigs (Degussa-Huls, 1992).
Justification for selection of skin sensitisation endpoint:
The assessment of skin sensitisation is based on a weight of evidence approach from two studies, one each on the registration substance itself and on a relevant surrogate substance.
Respiratory sensitisation
Endpoint conclusion
- Endpoint conclusion:
- no study available
Justification for classification or non-classification
Based on the weight of evidence tetrapropyl orthosilicate is not classified for skin sensitisation according to Regulation (EC) No 1272/2008.
Information on Registered Substances comes from registration dossiers which have been assigned a registration number. The assignment of a registration number does however not guarantee that the information in the dossier is correct or that the dossier is compliant with Regulation (EC) No 1907/2006 (the REACH Regulation). This information has not been reviewed or verified by the Agency or any other authority. The content is subject to change without prior notice.
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