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Administrative data

Key value for chemical safety assessment

Genetic toxicity in vitro

Description of key information

Bacterial mutagenicity: negative, with and without metabolic activation in Salmonella typhimurium strains TA 98, TA 100, TA 1535, TA 1537 or E. coli WP2 uvrA (OECD 471) (Bioreliance, 2001).

Cytogenicity in mammalian cells: negative, with and without metabolic activation in V79 cells (OECD 473) (Eurofins, 2017).

Mutagenicity in mammalian cells: negative, with and without metabolic activation in mouse lymphoma L5178Y (OECD 490) (Eurofins, 2018).

Endpoint conclusion
Endpoint conclusion:
no adverse effect observed (negative)

Genetic toxicity in vivo

Endpoint conclusion
Endpoint conclusion:
no study available

Additional information

3 -Trimethoxysilylpropane-1-thiol has been tested in a valid bacterial reverse mutation assay, according to the OECD TG 471 (1997), and under GLP, using Salmonella typhimurium strains TA 98, TA 100, TA 1535, TA 1537 or E. coli WP2 uvrA (Bioreliance, 2001).

No increase in the number of revertants was observed in any test strain, with or without metabolic activation. Appropriate positive and solvent controls were added and gave expected results. It is concluded that the test substance is negative for mutagenicity to bacteria under the conditions of the test.

In another bacterial mutagenicity study (Evonik, 1989), which was comparable to guideline, a positive result was reported in S. typhimurium TA 1538 only, with and without metabolic activation. These results, however, are not supported by the key study (BioReliance, 2001) and another two reliable bacterial mutagenicity studies (Wacker, 1990; Evonik, 1988). Therefore, the test substance is considered to be negative for mutagenicity to bacteria.

3-Trimethoxysilylpropane-1-thiol has been tested for ability to cause chromosome aberrations in Chinese hamster V79 cells according to OECD TG 473 and under GLP (Eurofins, 2018). No increase in the number of cells with aberrations was observed in experiment I with metabolic activation, 4-hour exposure, or in experiment 2 without activation, 21-hour exposure. An increase of aberrant cells above the historical control range was observed in experiment I without metabolic activation, 4-hour exposure, at concentrations of 1.0 mM and higher. These results varied between the duplicate cultures and the mean increase was not reflected by both cultures. These inductions were considered to be not biologically relevant. To verify the outcome of the first experiment without metabolic activation, a repetition experiment was performed. In the repeat of experiment I without metabolic activation, no biologically relevant increase above the historical control range was observed. Appropriate solvent, negative (treatment medium) and positive controls were included and gave expected results. It is concluded that the test substance is negative for the induction of chromosome aberrations under the conditions of this study.

3-Trimethoxysilylpropane-1-thiol (CAS 4420-74-0) has been tested for mutagenicity to mammalian cells in mouse lymphoma L5178Y cells according to OECD TG 490, and under GLP (Eurofins, 2018). No test-substance induced increase in the number of mutations was observed when tested up to precipitating concentration. Appropriate solvent, negative (treatment medium) and positive controls were included and gave expected results. It is concluded that the test substance is negative for mutagenicity to mammalian cells under the conditions of the study.

Justification for classification or non-classification

Based on the available data, no classification for mutagenicity is required for 3-trimethoxysilylpropane-1-thiol according to Regulation (EC) No 1272/2008.