2-butanone-O,O',O''-(phenylsilylidyne)trioxime

Endpoint summary

Additional information

Key study: A bacterial reverse mutation assay was performed in an equivalent method to OECD 471 with S. typhimurium tester strains TA98, TA100, TA1535 and TA1537 and E. coli tester strain WP2 uvrA in the presence and absence of Aroclor-induced rat liver S9 up to 5000 µg/plate test item concentration. Under the conditions of this study, test article was concluded to be negative.

Key study: An in-vitro chromosomal aberrations test in human lymphocytes was performed according to OECD Guideline 473. Lymphocytes were exposed up to1600 µg/ml test item, with and without S9 mix. In both the absence and presence of S9 mix, test item caused no statistically significant increase in the proportion of metaphase figures containing chromosomal aberrations, at any dose level, when compared with the solvent control. No statistically significant increases in the proportion of polyploid cells were seen. In conclusion, no evidence of clastogenic activity was observed in this in vitro cytogenetic test system.

Key study: Read-across from an analogue substnace: A Mouse Lymphoma L5178Y mammalian cell mutagenicity test was performed on the analogue butanone oxime up to 6.5 µg/plate in accordance with a test method similar to OECD Guideline 476. Based on the read-across approach, 2-butanone-O,O',O''- (phenylsilylidyne)trioxime was determined to be non-mutagenic with metabolic activation and mutagenic without metabolic activation but in presence of cytotoxicity under test conditions.

Key study: An in-vivo mammalian erythrocyte micronucleous test was performed with test item according to EEC method B12 and OECD guideline 474. Mice were treated with a single intraperitoneal administration of the test substance at dose levels of 0 (control) 500, 1000 and 2000 mg/kg bw (based on a preliminary toxicity test results) in dry corn oil. Bone marrow smears were obtained at 24 and 48 hours after dosing. Since the test substance did not cause any significant increase in the incidence of micronucleated immature erythrocytes, it was concluded that the test item did not show any evidence of causing chromosome damage when administered by intraperitoneal injection in-vivo to mcie.

Justification for selection of genetic toxicity endpoint
No study was selected, since the studies were negative in a weight of evidence approach.

Short description of key information:
Key study: Test method equivalent to OECD 471. GLP study. Test article was determined to be negative in the bacterial reverse mutation assay.
Key study: Test method according to OECD 473. GLP study. Test item did not show any clastogenic activity in the in-vitro cytogenetic test.
Key study: Test method similar to OECD 476 (read-across). Based on read-across approach from the experimental data on the analogue butanone oxime, it cannot be concluded that 2-butanone-O,O',O''- (phenylsilylidyne)trioxime induces gene mutation in mammalian cells.
Key study: Test method according to OECD 474. GLP study. The test item did not show any evidence of causing chromosome damage when administered by intraperitoneal injection in in-vivo to mice.

Endpoint Conclusion: No adverse effect observed (negative)

Justification for classification or non-classification

Based on the available information on genetic toxicity in-vitro and in-vivo, the test substance was determined to be negative for genetic toxicity, and therefore the substance is not classified according to CLP Regulation (EC) No 1272/2008.