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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.

The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.

Diss Factsheets

Administrative data

Key value for chemical safety assessment

Genetic toxicity in vitro

Description of key information

Mutagenic effects - bacterial: Ames study. Negative. OECD 471; Reliability = 1.

Clastogenic effects - mammalian: Chromosome aberrations in human peripheral blood lymphocytes. Positive for the induction of structural chromosome aberrations and negative for the induction of numerical chromosome aberrations in CHO cells. OECD 473; Reliability = 1.

Endpoint conclusion
Endpoint conclusion:
adverse effect observed (positive)

Genetic toxicity in vivo

Description of key information

Clastogenic effects - mammalian: in vivo mouse micronucleus study; Negative. OECD 474; Reliability = 1

Clastogenic effects - mammalian: in vivo chromosome aberration study; Negative; OECD 475; Reliability =1

DNA damage/repair - mammalian: in vivo unscheduled DNA synthesis (UDS); Negative (read-across substance); OECD 486; Reliability = 1

DNA damage/repair - mammalian: in vivo Comet assay; Negative; OECD 489; Reliability = 1

Endpoint conclusion
Endpoint conclusion:
no adverse effect observed (negative)

Additional information

A bacterial reverse mutation assay was conducted in Salmonella typhimurium stains TA98, TA100, TA102, TA1535, and TA1537. The test item was then tested in 2 independent experiment, with and without a metabolic activation system. Both experiments were performed according to the direct plate incorporation method except for the second test with S9 mix, which was performed according to the preincubation method (60 minutes, 37°C). The selected treatment levels were 312.5, 625, 1250, 2500, and 5000 µg/plate for both mutagenicity experiments with and without S9 mix. No toxicity was noted toward all the strains used, both with and without S9 mix. The test item did not induce any noteworthy increase in the number of revertants, both with and without S9 mix, in any of the 5 strains. Under the experimental conditions, the test item does not show any mutagenic activity in the bacterial reverse mutation test with Salmonella typhimurium, with and without S9 mix up to 5000 µg/plate expressed as active material.

 

The test substance was tested in the chromosome aberration assay using Chinese hamster ovary (CHO) cells in both the absence and presence of an Aroclor-induced S9 activation system.

The doses chosen for the chromosome aberration assay ranged from 12.5 to 300 μg/mL for all three treatment groups. The percentage of cells with structural aberrations in the S9-activated 4-hour exposure group was statistically increased (21.0%) above that of the solvent control at 300 μg/mL. The percentage of cells with numerical aberrations was statistically increased above that of the solvent control at dose levels 50 and 150 μg/mL. However, the percentages of cells with numerical aberrations at 50 and 150 μg/mL (6.5% and 6.0%, respectively) were within the historical solvent control range of 0.0% to 10.0%. Therefore, they were not considered to be biologically significant. The percentage of cells with structural or numerical aberrations in the non-activated 20-hour exposure group was not significantly increased above that of the solvent control at any dose level. Due to lack of a dose level with close to 50% reduction in cell growth or mitotic index, the chromosome aberration assay was repeated in the non-activated 4-hour exposure group at the same doses used in the initial assay (12.5, 25, 50, 100, 150, 200, 250 and 300 μg/mL). The percentage of cells with structural aberrations in the non-activated 4-hour exposure group was statistically increased (23.0%) above that of the solvent control at 300 μg/mL. The Cochran-Armitage test was also positive for a dose response. The percentage of cells with numerical aberrations in the test substance-treated group was not significantly increased above that of the solvent control at any dose level. Based on the findings of this study, the test substance was concluded to be positive for the induction of structural chromosome aberrations and negative for the induction of numerical chromosome aberrations in CHO cells in both non-activated and S9-activated test systems.

 

An in vivo cytogenetics study was conducted to evaluate whether or not the test substance is capable of inducing clastogenic damage in the mouse bone marrow micronucleus test. The test system positive control, cyclophosphamide, induced statistically significant and biologically meaningful increases in micronucleated polychromatic erythrocytes, compared to vehicle control values, thus demonstrating the sensitivity of the test system to a known clastogen. The test substance was tested up to doses of 2000 mg/kg body weight in both male and female mice. No statistically or biologically significant increases in the incidence of micronucleated polychromatic erythrocytes, over vehicle control values, were seen in either the 24-hour or 48-hour sampling time. Under the conditions of the test, the test substance is not clastogenic in the mouse bone marrow micronucleus test.

 

The test substance was tested for genotoxic (clastogenic) potential by conducting a chromosome aberration assay. Mice were treated either with the vehicle control or with the test substance at doses of 500, 1000 or 2000 mg/kg. No statistically significant or biologically relevant reductions in the PCEs/ECs ratio in the test substance-treated groups relative to the respective vehicle controls were observed. No statistically significant or biologically relevant increase was observed in the incidence of structural or numerical chromosome aberrations in test substance-treated groups relative to the respective vehicle control groups in male or female mice at 24 or 48-hour after dose administration. Observed reductions in mitotic index suggest that the test substance reached the target cells. The test substance was negative for induction of chromosome aberrations in bone marrow cells.

 

An in vivo rat liver unscheduled DNA synthesis assay was conducted to evaluate whether or not the test substance was capable of inducing DNA damage, and consequently DNA repair, in the rat liver in vivo. The test substance was tested at doses of 500, 1000, and 2000 mg/kg body weight. No significant adverse reactions to treatment were observed for rats dosed with the test substance. The test substance did not induce a significant increase in the mean number of net nuclear grain counts (i.e., an increase of at least 5 counts over the vehicle control group) in hepatocytes isolated either 2 to 4 hours or 12 to 16 hours after dose administration. Under the conditions of the test, the test substance did not induce DNA repair, as measured by unscheduled DNA synthesis, in the rat liver in vivo.

 

In an in vivo Comet assay with a related test substance, no DNA damage was induced in the liver and stomach of rats treated up to 2000 mg/kg/day (the maximum recommended dose for in vivo Comet studies according to current regulatory guidelines).

Justification for classification or non-classification

The test substance was positive for the induction of structural chromosome aberrations. However, it was negative for the induction of numerical chromosome aberrations and negative for mutagenicity when evaluated in bacterial cultures. Additionally, it was negative in in vivo micronucleus, chromosome aberration, unscheduled DNA synthesis assays. Supporting these findings, is a Comet assay with a related test substance, which was also negative. Based on an assessment of the robust genetic toxicity data for this substance, the substance does not need to be classified for mutagenicity according to EU Classification, Labelling and Packaging of Substances and Mixtures (CLP) Regulation (EC) No. 1272/2008.