2,11-Dioxa-3,10-disiladodecane, 3,3,10,10-tetramethoxy-

Endpoint summary

Additional information

Information is available for 1,6 -bis(trimethoxysilyl)hexane from reliable in vitro studies for mutagenicity to bacteria and cytogenicity in mammalian cells. In addition, a reliable in vivo micronucleus assay is available.

1,6-Bis(trimethoxysilyl)hexane has been tested for mutagenicity to bacteria in a study which was conducted according to the Japanese guideline MOL, No 76 (similar to OECD 471) and in compliance with GLP (Dow Corning, 1991). No evidence for a test-substance related increase in the number of revertants was observed with or without metabolic activation in the initial or repeat experiments using S. typhimurium TA 1535, TA 1537, TA 98 and TA 100 and E. coli WP2 uvr A. Appropriate positive and solvent controls were included and gave expected results. It is concluded that the test substance is negative for mutagenicity to bacteria under the conditions of the test.

1,6-Bis(trimethoxysilyl)hexane has been tested for cytogenicity with mammalian cells in a study which was conducted according to a protocol that is similar to OECD 473, and in compliance with GLP (Dow Corning, 1996). Evidence of a test substance induced dose-related increase in the number of cells with chromosome aberrations was observed with and without metabolic activation in Chinese hamster lung fibroblasts (Clone 11). Appropriate positive and solvent controls were included and gave expected results. It is concluded that the test substance is positive for cytogenicity under the conditions of the test.

In vitro mammalian mutagenicity testing is not required as a positive result was obtained in the in vitro cytogenicity assay.

1,6-Bis(trimethoxysilyl)hexane has been tested in an in vivo rat micronucleus assay which was conducted according to OECD 474 and in compliance with GLP (BioReliance, 2010). No evidence of test substance related induction of micronuclei was observed following administration of the test substance by oral gavage at doses of 500, 1000 and 2000 mg/kg bw. No reduction in the ratio of PCEs to total erythrocytes was observed. Appropriate vehicle and positive controls were included and gave expected results. It is concluded that the test substance is not clastogenic under the conditions of the test.

As the evidence for potential for induction of damage to chromosomes that was obtained in the in vitro study was not confirmed when an in vivo micronucleus assay was carried out, it is considered that no further testing is required, and the registered substance is not genotoxic.

Short description of key information:
In vitro:
Gene mutation (Bacterial reverse mutation assay / Ames test): negative with and without metabolic activation in S. typhimurium TA 1535, TA 1537, TA 98 and TA 100 and E. coli WP2 uvr A (similar to OECD 471) (Hita Research Laboratories , 1991).
Cytogenicity in mammalian cells: positive with and without metabolic activation in Chinese hamster lung fibroblasts (Clone 11) (similar to OECD 473) (Hita Research Laboratories, 1996b).
In vivo:
Micronucleus assay in rat (oral gavage study): negative in male Sprague Dawley rats at doses of 500, 1000 and 2000 mg/kg bw (OECD 474) (BioReliance, 2010).

Endpoint Conclusion: No adverse effect observed (negative)

Justification for classification or non-classification

The evidence for clastogenicity obtained from an in vitro chromosome aberration study was not confirmed in an in vivo micronucleus assay, so 1,6-bis(trimethoxysilyl)hexane is not classified for mutagenicity to germ cells according to Regulation (EC) No 1272/2008.