3,3'-[(2,5-dichloro-p-phenylene)bis[imino(1-acetyl-2-oxoethylene)azo]]bis[4-chloro-N-(5-chloro-o-tolyl)benzamide]

Endpoint summary

Key value for chemical safety assessment

Genetic toxicity in vitro

Description of key information

in vitro: Ames: negative; OECD 471, study with target substance and read-across with CAS 5280-80-8, CAS 5580-57-4, CAS 79953-85-8 and CAS 5580-58-5
Chromosome aberration: negative; OECD 473; read-across with CAS 5280-80-8

HPRT: negative; OECD 476; read-across with CAS 5280-80-8

Mouse lymphoma assay: negative; OECD 476

 

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (negative)

Genetic toxicity in vivo

Description of key information

In vivo genotoxicity study does not need to be conducted since all in vitro gene and cytogenetic mutation studies were all negative.

Additional information

Reliable data from several studies on genetic toxicity are summarized in the table below: 

	PY 93	PY 94	PY 95	PY 128	155
	5580-57-4	5580-58-5	5280-80-8	79953-85-8	68516-73-4
Bacterial mutagenicity	Negative K1 Non Prival	Negative K1 Prival	Negative K2 Non Prival	Negative K1 Non Prival	Negative K2 Non Prival
Clastogenicity in vitro			Non clastogenic K1		No indications of clastogenicity seen in the MLA
Mutagenicity in mammalian cells in vitro			Negative K1		Negative K1
Micronucleus test  in vitro	Negative K1	Negative K1		Negative K1	Negative K1

 

Bacterial gene mutation:
Mutagenicity in bacterial reverse mutation assays (Ames test) have been investigated with all members of the 'yellow disazo condensation pigments' (CAS 5580-57-4, 5280-80-8, 68516-73-4, 79953-85-8, and 5580-58-5). Pigment Yellow 94 was tested using the Prival modification for azo substances. The pigments do contain an azo function which is embedded in a larger conjugated system and probably not accessible to enzymes.
Negative results were obtained in all tests with and without metabolic activation. All relevant tester stains were tested and test item concentrations were adequate.
 
Mammalian gene mutation:

Mutagenicity in mammalian cells has been investigated in two reliable studies according to OECD guideline 476 with CAS 5280-80-8 (Harlan Cytotest Cell Research GmbH, 2012) and with CAS 68516-73-4 (BASF, 2012). Whereas the latter is the smallest molecule of the group, the other is the one containing as building blocks the most critical aromatic amines. The GLP guideline study with CAS 5280-80-8 was performed to investigate the potential of the test substance to induce gene mutations at the HPRT locus in V79 cells of the Chinese hamster. The assay was performed in two independent experiments, using two parallel cultures each. The first main experiment was performed with and without liver microsomal activation and a treatment period of 4 hours. The second experiment was performed with a treatment time of 4 hours with and 24 hours without metabolic activation. The highest concentration applied in the pre-experiment (840 µg/mL) was limited by the suspendibility of the test item in aqueous medium. The concentration range of the main experiments was limited by the occurrence of precipitation of the test item. No substantial and reproducible dose dependent increase of the mutation frequency was observed up to the maximum concentration with and without metabolic activation. Appropriate reference mutagens (and DMBA), used as positive controls, induced a distinct increase in mutant colonies and thus, showed the sensitivity of the test system and the activity of the metabolic activation system. In conclusion it can be stated that under the experimental conditions reported the test item did not induce gene mutations at the HPRT locus in V79 cells. Therefore, the test substance is considered to be non-mutagenic in this HPRT assay.

Cytogenicity study in mammalian cells:

Clastogenicity in mammalian cells has been investigated in a reliable study with CAS 5280-80-8 (chromosome aberration test according to OECD 473, BSL, 2012), in reliable study with CAS 5580-58-5 (vitro micronucleus study OECD 487, 2021) and indications on the absence of clastogenic properties can also gained from the mouse lymphoma assay with CAS 68516-73-4. As all available information indicates that the pigments are not taken up by cells, studies were considered sufficient for in-vitro testing of clastogenicity.
CAS 5280-80-8 contains the most problematic amines as buidling blocks. In the GLP-compliant in-vitro study for clastogenicity, the chromosomes were prepared 20 h after start of treatmentwith the test item. The treatment interval was 4h with and without metabolic activation in experiment I. In experiment II, the treatment intervalwas 4 h with and 20h without rnetabolic activation. Duplicate cultures were treated at each concentration. 100 metaphasesper culture were scored for structural chromosomal aberrations. The following concentrations were evaluated for microscopicanalysis:
Experiment I:
without metabolic activation: 0.975, 7.8, 62.5, 125 and 250 µg/mL
with metabolic activation: 7.8, 250, 500 and 1000 µg/mL
Experiment II:
without metabolic activation: 62.5, 125, 250 and 500 µg/mL
with metabolic activation:10, 400, 750 and 900 µg/mL
The test item was prepared in cell culture medium (MEM). Precipitation of the test item were observed at the end of the treatment by the unaided eye with and without metabolic activation in experiment I and II.Toxic effects of the test item were noted with and without metabolic activation in experiment I and II. In both experiments, no biologically relevant increase of the aberration rates was noted after treatment with the test item with and without metabolic activation. The aberration rates of all dose groups treated with the test item were within the historical control data of the negative control. In the experiments I and II with and without metabolic activation no biologically relevant increase in the frequencies of polyploid cells was found after treatment with the test item as compared to the controls. The positive controls induced distinct and biologically relevant increases in cells with structural chromosomal aberrations.

 

Taking together all results, it is concluded that the 'yellow disazo condensation pigments' do not induce gene mutations and are non-clastogenic.  

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. Based on available data on genetic toxicity, the test item is not classified according to Regulation (EC) No 1272/2008 (CLP), as amended for the tenth time in Regulation (EU) No 2017/776.