3-[[4-[(2,6-dibromo-4-nitrophenyl)azo]phenyl]ethylamino]propiononitrile

Endpoint summary

Key value for chemical safety assessment

Genetic toxicity in vitro

Description of key information

Gene mutation assay in bacteria (AMES test, according to OECD 472): negative

An AMES test according to OECD 471 is in progress and expected to be negative

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (negative)

Additional information

Evaluation of available information on genotoxicity was done as reported in ECHA Guidance Chapter R.7a: Endpoint specific guidance, Version 5.0 – December 2016.

A preliminary assessment should normally include data from a gene mutation test in bacteria unless existing data for analogous substances indicates this would be inappropriate.

When the result of the bacterial test is positive, it is important to consider the possibility of the substance being genotoxic in mammalian cells.

In order to ensure the necessary minimum level of information is provided, at least a further test is required in addition to the gene mutation test in bacteria. This should be an in vitro mammalian cell test capable of detecting both structural and numerical chromosome aberrations. Suitable options are in vitro chromosome aberration test (OECD guideline 473), i.e. a cytogenetic assay for structural chromosome aberrations, or in vitro micronucleus test (OECD guideline 487), i.e. a cytogenetic assay to detect not only structural chromosomal aberrations but also aneuploidy. It is possible to present data from an in vivo cytogenetic test as an alternative to the first in vitro mammalian cell test. For instance, if an adequately performed in vivo micronucleus test is available, it may be presented as an alternative.

An in vitro gene mutation study in mammalian cells (OECD guideline 476) is taken into account to complete the assessment.

In general, substances that are:

- positive in the gene mutation test in bacteria,

- negative in in vitro or in vivo tests to measure chromosomal damage, e.g. chromosome aberration or micronucleus assays

- negative in in vitro or in vivo gene mutation tests, e.g. HPRT assay

may be considered as non-genotoxic.

The genotoxic potential of test item was assessed based on data on the substance itself .

In a study conducted according to OECD guideline 472, E.coli WP2 uvrA strain was tested in both standard plate test and preincubation test at concentrations of 0, 20, 100, 500, 2500 and 5000 µg/plate in DMSO.

No mutagenic effect was noted in E. coli Wp2 uvrA strain both in standard plate and preincubation assay.

An AMES test according to OECD guideline 472 is in progress and expected to be negative.

Justification for classification or non-classification

According to the CLP Regulation (EC 1272/2008), Annex I, Part 3, substances which cause concern for humans owing to the possibility that they may induce heritable mutations in the germ cells of humans are classified in Category 2. This classification is based on positive evidence obtained in:

— somatic cell mutagenicity tests in vivo, in mammals; or

— other in vivo somatic cell genotoxicity tests which are supported by positive results from in vitro mutagenicity assays.

Note: substances which are positive in in vitro mammalian mutagenicity assays, and which also show chemical structure activity relationship to known germ cell mutagens, shall be considered for classification as Category 2 mutagens.

In vitro mutagenicity tests are the following:

— in vitro mammalian chromosome aberration test;

— in vitro mammalian cell gene mutation test;

— bacterial reverse mutation tests.

The overall assessement on the genotoxic potential of test substance was based on: negtaive outcome in bacterial reverse mutation assay (AMES test OECD 472) and the AMES test (OECD 471) in progress and expected to be negative.

All studies were conducted according to OECD guidelines and have a high reliability.

Based on these results, test susbstance was considered as non genotoxic and it was not classified within the CLP Regulation (EC 1272/2008).