Sodium 4(-2-hydroxy-1-naphthylazo)naphthalenesulphonate

Endpoint summary

Key value for chemical safety assessment

Genetic toxicity in vitro

Description of key information

non mutagenic

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (negative)

Genetic toxicity in vivo

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information

GENETIC TOXICITY IN VITRO

The following data were obtained for the Similar Substance 01. It is expected that the Target substance will present similar profile related to the genetic toxicity potential. Justification for Read Across is given in Section 13 of IUCLID.

In order to evaluate the potential of the test item to induce reverse mutation in Salmonella typhimurium and Escherichia coli, an AMES study was performed according to the OECD Guideline No. 471 (1997). A preliminary toxicity test was performed to define the dose-levels of test substance to be used for the mutagenicity study. The test item was then tested in two independent experiments, with and without a metabolic activation system (S9 mix). The preliminary test and the first experiment were performed according to the direct plate incorporation method; while the second experiment with S9 mix was performed according to the preincubation method. Five strains of bacteria Salmonella typhimurium: TA 1535, TA 1537, TA98, TA100 and TA 102 and one strain of Escherichia coli: WP2 uvrA were used. Each strain was exposed to five dose-levels of the test item (three plates/dose-level) from. After 48 to 72 hours of incubation at 37 °C, the revertant colonies were scored. The evaluation of the toxicity was performed on the basis of the observation of the decrease in the number of revertant colonies and/or a thinning of the bacterial lawn. The test item was dissolved in water for injections. All concentrations and dose-levels were expressed as active item, taking into account the purity. Also the positive controls were included in the assay both with and without S9 mix.

The acceptance criteria were met. Since the test item was freely soluble and generally non-toxic in the preliminary test, the highest dose-level selected for the main test was 5000 µg/plate. The selected treatment-levels were from 312.5 to 5000 µg/plate, for both mutagenicity experiments, with and without S9 mix, except for the first experiment with the TA 98 and TA 1537 strains with S9 mix where the dose-levels were from 156.3 to 5000 µg/plate. No precipitate was observed in the Petri plates when scoring the revertants at all dose-levels. A moderate to marked toxicity was noted in the second experiment with S9 mix (preincubation method), in the TA 1535, TA 1537, TA 98 and TA 100 strains, generally at dose-levels > 2500 µg/plate. The test item did not induce any noteworthy increase in the number of revertants, both with and without S9 mix, in any of the six strains.

The test item did not show mutagenic activity in the bacterial reverse mutation test with Salmonella typhimurium and Escherichia coli under the experimental conditions.

Justification for classification or non-classification

According to the CLP Regulation (EC) No 1272/2008, for the purpose of the classification for germ cell mutagenicity, substances are allocated in one of two categories in consideration of the fact that they are:

- substances known to induce heritable mutations or to be regarded as if they induce heritable mutations in the germ cells of humans or substances known to induce heritable mutations in the germ cells of humans or

- substances which cause concern for humans owing to the possibility that they may induce heritable mutations in the germ cells of humans.

 

Based on the results of mutagenicity (AMES), no classification for mutagenetic toxicity is warranted under the CLP Regulation (EC) No 1272/2008.