1,1,1,3,5,5,5-heptamethyl-3-octyltrisiloxane

Endpoint summary

Key value for chemical safety assessment

Genetic toxicity in vitro

Description of key information

Bacterial reverse mutation assay: 1,1,1,3,5,5,5-heptamethyl-3-octyltrisiloxane was negative with and without metabolic activation in S. typhimurium TA 97s, TA 98, TA 100, TA 102 and TA 1535 (OECD TG 471) (Noack-Laboratorium, 2001).
Mammalian mutagenicity study: 1,1,1,3,5,5,5-heptamethyl-3-octyltrisiloxane was negative with and without metabolic activation in mouse lymphoma L5178Y cells (OECD TG 490) (Eurofins, 2016).

The studies were conducted according to appropriate OECD guidelines or to similar protocols, and in compliance with GLP.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (negative)

Genetic toxicity in vivo

Description of key information

Mammalian micronucleus assay: 1,1,1,3,5,5,5-heptamethyl-3-octyltrisiloxane was negative in mouse bone marrow polychromatic erythrocytes (OECD TG 474) (CHV, 1995).

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (negative)

Additional information

1,1,1,3,5,5,5-Heptamethyl-3-octyltrisiloxane has been tested for mutagenicity to bacteria, in a study which was conducted according to the OECD TG 471, compliant with GLP (Noack-Laboratorium, 2001). No evidence of a test-substance related increase in the number of revertants was observed with or without metabolic activation in Salmonella typhimurium strains TA 97a, TA 98, TA 100, TA 1535, or TA 102 in the initial or the repeat experiments up to limit concentrations. Appropriate positive and solvent controls were included and gave the expected results. It is concluded that the test substance is negative for mutagenicity to bacteria under the conditions of the test.

A supporting bacterial mutagenicity study was available, which confirmed the results from the key study (BRRC, 1995). 1,1,1,3,5,5,5-heptamethyl-3-octyltrisiloxane has been tested for mutagenicity to bacteria, in a study which was conducted according to the OECD TG 471 with acceptable restrictions, and compliant with GLP. No evidence of a test-substance related increase in the number of revertants was observed with or without metabolic activation in Salmonella typhimurium strains TA 98, TA 100, TA 1535, TA 1537 or TA 1538 in the initial or the repeat experiments up to limit concentrations. Appropriate positive and solvent controls were included and gave the expected results. It is concluded that the test substance is negative for mutagenicity to bacteria under the conditions of the test.

1,1,1,3,5,5,5-Heptamethyl-3-octyltrisiloxane has been tested in a valid study according to OECD 490 and under GLP. No statistically or biologically significant increase in the mutant frequency was observed with or without metabolic activation when tested up to limit concentrations in mouse lymphoma L5178Y cells. It is concluded that the test substance is negative for mutagenicity to mammalian cells under the conditions of the test.

1,1,1,3,5,5,5-Heptamethyl-3-octyltrisiloxane has been tested for ability to induce micronuclei in mouse bone marrow polychromatic erythrocytes, in a study conducted according to OECD TG 474 with acceptable restrictions, and in compliance with GLP (CHV, 1995). No increase in the number of micronuclei was observed when test substance was administered by intraperitonal injection up to limit concentration. No toxicity to bone marrow was observed as evaluated by the ratio of polychromatic erythrocytes to normochromatic erythrocytes. Appropriate solvent and positive controls were included and gave expected results. It is concluded that the test substance is negative for the induction of micronuclei under the conditions of this study.

Justification for classification or non-classification

Based on the available data for 1,1,1,3,5,5,5 -heptamethyl-3-octyltrisiloxane, no classification is required for genetic toxicity according to Regulation (EC) No. 1272/2008.