(3-chloropropyl)diethoxymethylsilane

Endpoint summary

Additional information

Studies were chosen as key when the available study was of relevance and of sufficient quality for classification, labelling and for risk assessment. 

The key bacterial mutagenicity study on (3-chloropropyl)diethoxymethylsilane was conducted according to OECD TG 471 and under GLP, the test substance induced a mutagenic effect in S. typhimurium TA 1535 with and without metabolic activation. Appropriate positive and solvent controls were included and gave expected results. The test substance is considered to be a direct-acting mutagen, inducing base pair mutations (Hüls AG,1995).

No data are available for mutagenicity to a bacterial strain capable of detecting cross-linking or oxidising mutagens. In view of the lack of genetic toxicity demonstrated in studies on mammalian cells [and in vivo], and the absence of structural features that indicate that such mutagenicity is likely,testing in an appropriate 5^th strain is not considered necessary. In addition, the only silicon-containing substance which has given a positive result in a bacterial strain capable of detecting cross-linking or oxidising mutagens contains an epoxy- side-chain (which is associated with cross-linking mutagenicity), and this substance was positive in Salmonella typhimurium strains TA 100, TA 1535 as well as in E.coli WP2 uvrA.

 

The key mammalian cell gene mutation study on (3-chloropropyl)diethoxymethylsilane was conducted according to OCED TG 476 and under GLP, the test substance was non-mutagenic in CHO cells under the conditions of the test. Appropriate positive and solvent controls were included and gave expected results (Hüls AG,1997f).

 

The key in vivo erythrocyte micronucleus study on (3-chloropropyl)diethoxymethylsilane was conducted according to EU Method B.12 and under GLP, the test substance was not genotoxic under the conditions of the test. Appropriate positive and solvent controls were included and gave expected results.  It should be noted that the PCE / NCE ratio was reduced in the test substance indicating toxicity to bone marrow and demonstrating that the test substance reached the target tissue (Hüls AG,1996).

The test substance was considered to be a direct-acting mutagen after a bacterial reverse mutation assay. Further mutagenicity testing in mammalian cells in contrast was negative, indicating that the effect observed in bacteria was not relevant to mammalian cells. In vitro cytogenicity testing is not required as there is a reliable in vivo micronucleus study available. The results of this study were also negative, confirming the conclusion from the in vitro studies that the test substance has no genotoxic potential.

Justification for selection of genetic toxicity endpoint
No study was selected, since all available studies were negative.

Short description of key information:
In vitro:

Gene mutation (Bacterial reverse mutation assay/ Ames test): Salmonella typhimurium strain: TA 100, TA 98, TA 1535 and TA 1537: Positive with and without metabolic activation in strain TA 1535 (equivalent or similar to OECD 471).

Mammalian gene mutation (Chinese hamster ovary cell gene mutation assay): Negative with and without metabolic activation (according to OECD 476).

In vivo:

Chromosome aberration (in vivo erythrocyte micronucleus assay): Negative (according to EU Method B.12).

Endpoint Conclusion: No adverse effect observed (negative)

Justification for classification or non-classification

Based on the available in vitro and in vivo data on mutagenicity of the registered substance, (3-chloropropyl)diethoxymethylsilane is not classified for mutagenicity according to Regulation (EC) 1272/2008 or Directive 67/548/EEC.