2-Propanone, 2,2',2''-[O,O',O''-(ethylsilylidyne)trioxime]

Endpoint summary

Additional information

In vitro gene mutation in bacteria: read-across approach from experimental data on analogue substances:

Weight of evidence: A standard NTP (National Toxicology Program) protocol was performed to investigate the mutagenicity of Acetoxime. Different concentrations of test substance (from 100 to 10000 µg/plate) were tested in Salmonella typhimurium TA100, TA 97, TA 1535, and TA 98 by the preincubation assay with and without metabolic activation. Acetoxime showed no mutagenicity in any tested strain, with or without metabolic activation. Based on these results, the read-across approach was performed and EAC3 was also considered to be non-mutagenic under test conditions.

Weight of evidence: Two bacterial reverse mutation assays (OECD Guideline 471 and GLP) were performed for Wasox-VMAC2 and Wasox-MMAC2 with strains of Salmonella typhimurium TA97a, TA98, TA100, TA102 and TA1535. Plate incorporation method was carried out at concentrations up to 5000 µg/plate in the presence and absence of metabolic activation. In none of the concentrations tested a significant increase of the mutation frequency was obtained. Based on these results, the read-across approach was applied and EAC3 was determined to be non-mutagenic under test conditions.

Supporting study: The mutagenicity of Acetone oxime at up to 100 µmoles/ plate was tested in Salmonella typhimurium TA98, TA100, TA2637 and E. coli WP2 uvrA/pKM101 by the preincubation assay with or without metabolic activation. Acetone oxime showed no mutagenicity in any tested strain, both with or without metabolic activation. Based on these results, the read-across approach was applied and EAC3 was also considered to be non-mutagenic under test conditions.

According to the available data, the weight of evidence approach was applied and the test item EAC3 was determined to be negative for in vitro gene mutation in bacteria.

In vitro and in vivo mammalian chromosome aberration: read-across from experimental data on analogue substances:

Weight of evidence (in vitro): Based on experimental data obtained in the in vitro chromosome aberration test in human lymphocytes (OECD Guideline 473 and GLP) with analogue substance Wasox-VMAC2 (positive without metabolic activation and 20 h treatment at 0.56 and 1.57 µL/mL; negative with and without metabolic activation at 3 h treatment at up to 5.00 µL/mL), the read-across approach was applied and was determined that EAC3 induces structural chromosomal aberrations in cultured human lymphocytes after a treatment length of 20 hours in absence of a metabolic activation, under test conditions.

Weight of evidence (in vitro): Based on experimental data obtained in the in vitro chromosome aberration test in human lymphocytes (OECD Guideline 473 and GLP) with analogue substance Wasox-MMAC2 (negative with and without metabolic activation up to 5.00 µL/mL), the read-across approach was applied and was considered that under study conditions, there was no evidence that EAC3 induces structural chromosomal aberrations in cultured human Lymphocytes, neither without nor with the use of a metabolic activation system.

Key study (in vivo): The Mammalian Erythrocyte Micronucleus Test (OECD Guideline 474 and GLP) was performed to detect the possible formation of micronuclei, induced by the analogue substance Wasox-VMAC2, as a result of chromosomal damage or of a damage to the mitotic apparatus of Crl:NMRI BR-mice. The test substance did not produce relevant increases of the numbers of micronuclei in polychromatic erythrocytes in animals of either sex of the test species at doses of 1000, 1500 or 2000 mg per kg body mass and sampling times of 24 and 48 hours after administration. Based on the experimental data the read-across approach was applied and EAC3 was also considered not to produce micronuclei increases in polychromatic erythrocytes under test conditions.

According to the available data, the test item EAC3 was determined to be negative for in vitro cytoneginicity in mammalian cells.

In vitro gene mutation in mammalian cells: read-across approach from experimental results on an analogue substance:

Key study: An in vitro mammalian cell assay was performed in mouse lymphoma L5178Y TK+/- 3.7.2 C cells at the tk locus to test the potential of the analogue substance acetone oxime to cause gene mutation and/or chromosome damage. Treatment was performed for 3 hours with and without metabolic activation (±S9 mix) and for 24 hours without metabolic activation (-S9 mix) up to 5000 µg/mL test item in DMSO. No biologically relevant or statistically significant increase in the mutation frequency was observed at the evaluated concentrations. No significant dose response to the treatment was indicated by the linear trend analysis. Based on these results, the read-across approach was applied and EAC3 was determined to be non mutagenic either in the presence or in the absence of metabolic activation system under the conditions of this Mouse Lymphoma Assay.

According to the available data, the test item EAC3 was determined to be negative for in vitro gene mutation in mammalian cells.

Justification for selection of genetic toxicity endpoint
No study was selected, since all available studies were negative.

Short description of key information:
Genetic toxicity in vitro:
In vitro gene mutation in bacteria: Weight of evidence: Read-across from analogues. Read-across analysis showed that EAC3 is not mutagenic in all strains/cell types with and without metabolic activation (OECD Guideline 471 and GLP).
In vitro cytogenicity study in mammalian cells: Weight of evidence: read-across from analogues. Read-across analysis showed that EAC3 is negative against chromosomal aberrations with and without S9 (OECD Guideline 473 and GLP).
In vitro gene mutation study in mammalian cells: Key study: read-across from analogues. Read-across analysis showed that EAC3 is negative for the in vitro gene mutation assay in mammalian cells, with and without S9 (OECD Guideline 476 and GLP).
Studies on DNA repair synthesis in mammalian cells on analogue substances (method similar to OECD 482) supported these results since based on read-across approach EAC3 was determined to be negative.
Genetic toxicity in vivo:
Key study: read-across from analogue: read-across analysis shows that EAC3 is negative in the mammalian erythrocyte micronucleus test (OECD Guideline 474 and GLP).

Endpoint Conclusion: No adverse effect observed (negative)

Justification for classification or non-classification

Based on the available information on genetic toxicity in vitro (bacterial reverse mutation assay, chromosome aberration and gene mutation in mammalian cells) and in vivo (mammalian erythrocyte micronucleous test) the substance EAC3 is considered to be negative for genetic toxicity, and therefore, the substance is not classified in accordance with CLP Regulation (EC) no 1272/2008.