2,7-NAPHTHALENEDISULFONIC ACID 5-[[4-CHLORO-6-(ETHYLPHENYLAMINO)-1,3,5-TRIAZIN-2-YL]AMINO]-3-[[5-[(2,3-DIBROMO-1-OXOPROPYL)AMINO]-2-SULFOPHENYL]AZO]-4-HYDROXY-,SODIUM SALT

Endpoint summary

Additional information

In vitro:

In a GLP compliant mutagenicity test, performed according to OECD guideline 471, 5 Salmonella typhimurium strains (TA 1535, TA 1537, TA 98, TA 100, and 102) and one E. Coli strain (WP2 uvrA) were used to test the mutagenic potential of the test substance both with and without metabolic activation (Ciba-Geigy 1994). In both experiments, performed with and without metabolic activation on strain S. typhimurium TA 100, the test substance led to a minor increase in the number of back-mutants at the highest concentration of 8333.0 µg/plate only. These negligible effect is, however, not sufficient as indication of a mutagenic property of the test substance. An occasionally observed slight increase in the number of revenants with strains S. typhimurium TA 102 and E. coli WP2 uvrA was not reproducible and therefore did not fulfill the criteria for a positive response. No other differences were observed.From the results obtained, it is concluded that there is no evidence of induction of gene mutations by the test substance and its metabolites in the strains of S. typhimurium and E. coli used.

In a GLP-compliant chromosome aberration test, tested according to OECD guideline 473, Chinese hamster ovary cells (CHO K1) were exposed to the test substance with and without metabolic activation (Ciba-Geigy 1994). A pretest was performed to determine the toxicity of the test substance followed by a original and confirmatory mutagenicity study. In the confirmatory experiment performed without metabolic activation and in the original and confirmatory experiments with metabolic activation statistically significant increased numbers of metaphases containing specific chromosomal aberrations were observed. In the experiments with activation the incidences of aberrant metaphases were clearly concentration-dependent. It is concluded that the test substance and its metabolites exerted a clear-cut clastogenic effect in Chinese hamster ovary cells in vitro.

In a mammalian cell gene mutation assay (HPRT locus), V79 cells cultured in vitro were exposed to the test substance dissolved in MEM (+ 0% FBS 4h treatment; + 10% FBS 20h treatment) at concentrations of 25, 100, 125, 150, 175, 200, 225 and 250 µg/mL (without metabolic activation, Experiment I); 2.5, 5, 10, 25, 50, 100, 200, 400 and 500 µg/mL (with metabolic activation, Experiment I); 10, 25, 50, 100, 150, 200, 250, 300 and 350 µg/mL (without metabolic activation, Experiment II); 3.16, 10.0, 31.6, 100, 250, 325, 400, 440, 475 and 510 µg/mL (with metabolic activation, Experiment II). (BSL Bioservice 2013) Experiment I with and without metabolic activation and experiment II with metabolic activation were performed as a 4h short-term exposure assay. Experiment II without metabolic activation was performed as 20 h long term exposure assay. No precipitation was noted in the experiments. Biologically relevant growth inhibition was observed in experiment I and II with and without metabolic activation. In experiment I without metabolic activation the relative growth was 16.4% for the highest concentration (250 µg/mL) evaluated. The highest biologically relevant concentration evaluated with metabolic activation was 500 µg/mL with a relative growth of 11.9%. In experiment II without metabolic activation the relative growth was 11.2% for the highest concentration (350 µg/mL) evaluated. The highest concentration evaluated with metabolic activation was 510 µg/mL with a relative growth of 12.9%. In both experiments no biologically relevant increase of mutants was found after treatment with the test substance. No dose-response relationship was observed. The positive controls did induce the appropriate response. In conclusion, under the conditions of the test, the test substance is considered to be non-mutagenic in the HPRT locus using V79 cells of the Chinese Hamster.

In vivo:

In a GLP-compliant micronucleus test, performed according to OECD guideline 474, Tif: MAGf mice (5/sex/treatment group) were treated by oral gavage with the test substance (625, 1250, 2500 mg/kg bw) (Ciba-geigy 1994). From the high dose group and from the negative control group, animals were sacrificed 16, 24 and 48 hours thereafter. From the intermediate and the low dose group and from the positive control group animals were sacrificed 24 hours after application. Subsequently femoral bone marrow cells were prepared and polychromatic erythrocytes were scored for micronuclei. The high dose applied did not lead to visible symptoms of toxicity. In all dosage groups assessed at the different periods post treatment, no statistically significant increase in the number of micronucleated polychromatic erythrocytes was observed when compared with the respective negative control group. It was therefore concluded that under the given experimental conditions no evidence for clastogenic or aneugenic effects were obtained in mice treated with the test substance.

Short description of key information:
The test substance is considered to be mutagenic in the in vitro chromosomal aberration test, but not in the bacterial reverse mutation assay and the in vitro HPRT assay. The in vivo erythrocyte micronucleus test did not show any genetic toxicity.

Endpoint Conclusion: No adverse effect observed (negative)

Justification for classification or non-classification

Based on the available genotoxicity studies, the test substance does not need to be classified for genotoxicity according to the Directive 67/548/EEC and according to the EU Classification, Labelling and Packaging of Substances and Mixtures (CLP) Regulation (EC) No. 1272/2008