2,2'-[(3,3'-dimethoxy[1,1'-biphenyl]-4,4'-diyl)bis(azo)]bis[3-oxo-N-phenylbutyramide]

Endpoint summary

Key value for chemical safety assessment

Genetic toxicity in vitro

Description of key information

The substance was not mutagenic in bacteria, not clastogenic in a chinese hamster cell line and it did not induce micronuclei in human peripheral blood lymphocytes. All studies were performed according to OECD testing guidelines and GLP.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (negative)

Genetic toxicity in vivo

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information

Ames Tests

In a reverse gene mutation assay in bacteria, strains TA100, TA98, TA1535 and TA1537 of Salmonella typhimurium and Escherichia coli strain WP2 uvrA were exposed to the following test item concentrations in DMSO: 0, 4.88, 9.77, 19.5, 39.1, 78.1, 156, 313, 625, 1250, 2500 and 5000 µg/plate. The test was conducted in the presence and absence of Phenobarbital/5,6-benzoflavone pretreated rat liver S9 mix. However, as it had been already reported that o-dianisidine produced by the reduction of azo groups in the test substance was positive in an Ames test, an additional test exclusively on TA98 was performed by using the metabolic activation system enhancing the reduction of azo groups (Hamster S9 mix). As a result, the gene mutagenicity of the test item on bacteria was judged negative in both performed test.

In a reverse gene mutation assay in bacteria, strains TA1535, TA1537, TA102, TA98 and TA100 of S. typhimurium were treated with suspensions of the test item in dimethyl sulphoxide at concentrations 0, 50, 150, 500, 1500 and 5000 µg/plate (Experiment 1 and 2). The test was performed in the presence and absence of a hamster liver homogenate metabolising system (30 % liver S9 in modified co-factors). No significant increases in the frequency of revertant colonies were recorded for any of the bacterial strains, with any dose of the test item, either with or without metabolic activation. Therefore, the test item, was considered to be non-mutagenic under the conditions of this test.

Chromosome aberration test

In an in vitro chromosome aberration test, Chinese hamster lung cell line (CHL cells) were exposed to the test substance in carboxymethyl cellulose sodium at concentrations of 313, 625, 1250, 5000 µg/mL in the absence of S9 mix and 625, 1250, 2500, 5000 µg/mL in the presence of S9 mix. The test doses were determined according to the result of the cell growth inhibition test, and each 3 doses of 1250, 2500 and 5000 μg/ml were also subjected to the microscopic observation in the 24-hour treatment by the continuous treatment method. As a result, no induction of the chromosome aberration was found, either, similarly in the short-term treatment method, and it was thus judged negative.

MNT in vitro

The test item, dissolved in DMSO, was assessed for its potential to induce micronuclei in human peripheral blood lymphocytes (HPBL) in the absence and presence of a rat liver metabolising system (S9 mx). Based on the results of a preliminary toxicity study, the doses chosen for the micronucleus assay ranged from 0.25 to 30 μg/mL for all three treatment groups. In the micronucleus assay, the cells were treated for 4 and 24 hours in the non-activated test system and for 4 hours in the S9-activated test system. All cells were harvested 24 hours after treatment initiation. Substantial toxicity (≥ 55 ± 5 % cytotoxicity relative to the solvent control) was not observed at any dose level in all three treatment groups. The dose levels to score for micronuclei were based on visible precipitate in the treatment medium (the lowest precipitating dose and two lower doses) in all harvests. The percentage of cells with micronucleated binucleated cells in the test article-treated groups was not statistically significantly increased relative to solvent control at any dose level in the 4-hour treatment group either in the presence of or the absence of S9 or in the 24-hour treatment group in the absence of S9. The results for the positive and negative controls indicate that all criteria for a valid assay were met. Based on the findings of this study, the test item was negative for the induction of micronuclei in both non-activated and S9-activated test systems.

Justification for classification or non-classification

Classification, Labelling, and Packaging Regulation (EC) No 1272/2008

The available experimental test data are reliable and suitable for classification purposes under Regulation (EC) No 1272/2008. In none of the tests, a genotoxic response was observed. As a result the substance is not considered to be genotoxic under Regulation (EC) No 1272/2008,as amended for the seventh time in Regulation (EC) No 2015/1221.