Chlorodimethylvinylsilane

Endpoint summary

Additional information

Information is available from a reliable bacterial mutagenicity study for chloro(dimethyl)vinylsilane (CAS 1719-58-0). No further information is available for the registered substance, however, reliable data are available for the related substance dichloro(methyl)(vinyl)silane (CAS 124-70-9). Chloro(dimethyl)vinylsilane hydrolyses very rapidly to dimethyl(vinyl)silanol (half-life < 1 min at 25°C and pH 4, 7 and 9), and dichloro(methyl)(vinyl)silane hydrolyses very rapidly to methyl(vinyl)silanediol (half-life ca. <1 min at pH7)

. These silanols have the same functional groups as dimethyl(vinyl)silanol, including a vinyl group (which may be associated with genetic toxicity in some substances (Benigni et al, (2008)). No trends in genetic toxicity have been observed in mono- and di-chloro silanes and mono- and di- methyl silanes, therefore it is considered that read-across between the substances is appropriate. The structural analogue has been selected on the basis of similarity of functional group and hydrolysis rate. The bacterial mutagenicity data available for the structural analogue indicates a potential for genetic toxicity which was not confirmed in the in vitro studies on mammalian cells; the bacterial mutagenicity study on the registered substance gave a negative result so it is considered that read-across from this substance is conservative. Additional information is given in a supporting report (PFA, (2013aa) attached in Section 13 of the IUCLID 5 dossier. Data from other vinyl-containing structural analogues, and for the related silanol hydrolysis product trimethylsilanol (CAS 1066-40-6) are presented in the table below. It can be seen that a positive result was obtained in a bacterial mutagenicity assay with dichloro(methyl)(vinyl)silane; a negative result is available for the registered substance. The other positive result was obtained in an in vitro cytogenicity assay on trimethoxy(vinyl)silane, and was not confirmed in an in vivo micronucleus assay. As the weight of evidence of the vinyl containing substances is for lack of genetic toxicity, it is considered that read-across of negative results is justified.

CAS Number	Chemical Name	Bacterial mutagenicity	In vitro mammalian cytogenicity	In vitro mammalian mutagenicity	In vivo genotox
001719-58-0	Chloro(dimethyl)vinylsilane	Negative Leuschner, J. (2002)
000124-70-9	Dichloro(methyl)(vinyl)silane	Positive +MA Not cytotoxic San, R. H. C. and Blair Shelton, J. (1990)	Negative Morris, A. (2010)	Negative Harbell, (1991)
000075-94-5	Trichloro(vinyl)silane	Negative Shin Etsu (2009)
002768-02-7	Trimethoxyvinylsilane	Negative MHLW (2005a)	Positive +MA Not cytotoxic MHLW (2005b)	Negative Ebert. (1996)	Negative in micronucleus Slesinski. (1985)
000078-08-0	Triethoxy(vinyl)silane	Negative Bowles, A. J. (2002).	Negative Durward (2002)	Negative Harbell (1991)
1066-40-6	Trimethylsilanol	Negative Herbold. (1986)	Negative Jagannath, (1978)	Negative Litton Bionetics (1978)	Negative CA*Bioassay Systems Corporation (1982) Negative RDL** DCC (1983)

Chloro(dimethyl)vinylsilane has been tested in a reliable bacterial mutagenicity study conducted according to OECD TG 471 and under GLP. No evidence of mutagenicity was observed with or without metabolic activation in Salmonella typhimurium strains TA 98, TA 100, TA 102, TA 1535 and TA 1537. Appropriate positive and solvent controls were included and gave the expected results (Leuschner 2002).

Dichloro(methyl)(vinyl)silane has been tested in a valid and reliable in vitro chromosome aberration assay according to OECD TG 473 and under GLP. No increase in the frequency of aberrations resulting from treatment with the test substance was detected. The expected results were obtained with vehicle and positive controls. It is concluded that the test substance is negative for the induction of chromosome aberrations in mammalian cells under the conditions of the test (Morris 2010). The original study was considered reliability 1. Read-across to the registered substance is considered scientifically justified and is reliability 2.

Dichloro(methyl)(vinyl)silane has been tested in a valid study according to a method that appears to be similar to OECD TG 476, and under GLP, but full details of the protocol are not available. No increase in the mutant frequency was observed in the presence or absence of metabolic activation. Appropriate solvent and positive controls were included and gave the expected results. The results indicate that the test material was not mutagenic under the conditions of the test (Harbell 1991). The original study and the read-across are considered to be reliability 2.

In vivo testing is not required as the overall conclusion of the in vitro genetic toxicity studies is negative.

Short description of key information:
In vitro:
Gene mutation (Bacterial reverse mutation assay / Ames test): negative with and without activation in Salmonella typhimurium strains TA 198. TA 100, TA 102, TA 1535, TA 1537 (OECD TG 471) (Leuschner 2002).

Cytogenicity in mammalian cells: read-across from related substance Dichloro(methyl)(vinyl)silane 124-70-9: negative with and without metabolic activation in peripheral human lymphocytes (OECD 473) (Morris 2010).

Mutagenicity in mammalian cells: read-across from related substance Dichloro(methyl)(vinyl)silane 124-70-9: negative with and without metabolic activation in mouse lymphoma L5178Y cells (OECD 473) (Harbell 1991).

Endpoint Conclusion: No adverse effect observed (negative)

Justification for classification or non-classification

Based on the available in vitro genotoxicity data, chloro(dimethyl)vinylsilane is not classified for mutagenicity according to Regulation 1272/2008/EC