Registration Dossier

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:

In the key skin sensitisation study on read-across substance N-(dimethylvinylsilyl)-1,1-dimethyl-1-vinylsilylamine (Harlan Laboratories, 2012), no skin reactions were observed at challenge.


To reduce animal testing REACH recommends to make use of a read-across approach where appropriate based on the high accordance in properties relevant for the specific endpoint. In the case of sensitisation the relevant properties are structural similarity as well as physical-chemical properties in the same range. In the following paragraphs the proposed read-across from N-(dimethylvinylsilyl)-1,1-dimethyl-1-vinylsilylamine is described. Read-across hypothesis The hypothesis is that source and target substances have similar toxicological properties because they are structurally similar and hydrolyse to similar silicon-containing hydrolysis products and the same non-silicon containing hydrolysis product, ammonia. Ammonia does not have any adverse effects for sensitisation at the relevant concentrations based on publicly available information (OECD SIDS, 2007). Both hexamethyldisilazane and N-(dimethylvinylsilyl)-1,1-dimethyl-1-vinylsilylamine hydrolyse rapidly on contact with water, half-life less that 1 minute at pH 4, 7 and 9, to produce trimethylsilanol and ammonia or dimethylvinylsilanol and ammonia. Both substances and their respective silicon-containing hydrolysis products are structurally similar. Both parent substances are disilazanes, containing the Si-N-Si functional group.The registration substance (CAS 1185-55-3) has three methyl groups bounds to each silicon; the read-across substance (CAS 7691-02-3) has two methyl and one vinyl group bound to each silicon. Due to the presence of two vinyl groups, N-(dimethylvinylsilyl)-1,1-dimethyl-1-vinylsilylamine is expected to be more reactive than hexamethyldisilazane so represents potential worse-case for sensitisation. Therefore read-across from N-(dimethylvinylsilyl)-1,1-dimethyl-1-vinylsilylamine to hexamethyldisilazane is considered vaild for skin sensitisation.

Migrated from Short description of key information:
The key study for skin sensitisation, carried out according to the OECD 406 test guideline and in compliance with GLP reports no skin sensitisation potential in guinea pig (Harlan Laboratories 2012).

Justification for selection of skin sensitisation endpoint:
Study was conducted in accordance with an appropriate guideline and in compliance with GLP.

Respiratory sensitisation

Endpoint conclusion
Endpoint conclusion:
no study available

Justification for classification or non-classification

Based on the available data from read-across substance N-(dimethylvinylsilyl)-1,1-dimethyl-1-vinylsilylamine, hexamethyldisilazane does require classification for skin sensitisation according to Regulation (EC) No 1272/2008.