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Administrative data

Key value for chemical safety assessment

Additional information

Information is available from reliable studies for all the required in vitro endpoints, and in other in vitro studies and an in vivo study. Where there was more than one result for an endpoint the most reliable study available was chosen as key study. Where there was more than one reliable study, the most recent study was selected. The results of all the studies were in agreement.


Short description of key information:
Gene mutation (Bacterial reverse mutation assay / Ames test): negative with and without activation in all strains tested (similar to OECD TG 471)
Cytogenicity in mammalian cells: negative in L5178Y mouse lymphoma cells (similar to OECD TG 473)
Mutagenicity in mammalian cells: negative in L5178Y mouse lymphoma cells (similar to OECD TG 476)
In vivo:
Mammalian Bone Marrow Chromosome Aberration Test: Negative in rat (OECD TG 475)

Endpoint Conclusion: No adverse effect observed (negative)

Justification for classification or non-classification

The available information for the substance indicates that when tested in vitro, hexamethylcyclotrisiloxane (CAS number 541 -05 -9) did not induce mutations in bacterial or mammalian cells, nor chromosome aberrations in mammalian cells. In addition, the test substance did not induce mutations in yeast or sister chromatid exchanges in mammalian cells. An in vitro unscheduled DNA synthesis assay and an E coli pos A assay also gave negative results. The conclusion reached from the in vitro results is confirmed by the negative result obtained when the analogous substance was tested in vivo in a rat bone marrow chromosome aberration assay. Therefore it is considered that classification for mutagenicity is not required.