2-Naphthalenesulfonic acid, 6-amino-5-[2-[4-[[4-[bis(2-hydroxyethyl)amino]-6-[(2-sulfoethyl)amino]-1,3,5-triazin-2-yl]amino]-2-sulfophenyl]diazenyl]-4-hydroxy-, sodium salt (1:3)

Endpoint summary

Additional information

In vitro data

Bacterial reverse mutation

Two studies are available to assess the potential of the test material to cause gene mutation in bacterial strains. Both studies were conducted in accordance with standardised guidelines OECD 471 and EU Method B.13/14. In the first study, reported by Molinier (1995), five strains of Salmonella typhimurium (TA1535, TA1537, TA98, TA100 and TA102) were treated in the presence and absence of a metabolic activation system (S9 mix). In two separate assays, the test material did not induce any significant, reproducible increases in the observed number of revertant colonies in any of the tester strains used in the presence or absence of metabolic activation.

In the second study, reported by de Joufrey (1996b), four trains of Salmonella typhimurium (TA1535, TA1537, TA98 and TA100) and one strain of Escherichia coli (WP2 uvr A) were treated in the presence and absence of a metabolic activation system (S9 mix). In two separate assays, the test material did not induce any significant, reproducible increases in the observed number of revertant colonies in any of the tester strains used in the presence or absence of metabolic activation.

Chromosome aberration test in vitro

The potential of the test material to induce structural chromosomal aberrations was determined in a study performed in accordance with standardised guidelines OECD 473 and EU Method B.10. The test material was tested in two independent experiments, both with and without S9 mix. No preliminary toxicity test was performed. A wide range of treatment levels was used for the first experiment and dose levels for scoring of chromosome aberrations were selected on the basis of cytotoxicity indicated by reduction of mitotic index. For each culture, heparinised whole blood was added to culture medium containing a mitogen and incubated at 39 ºC in a humidified atmosphere of 5 % CO₂/ 95 % air, for 48 hours.

In the absence and presence of metabolic activation, no cytotoxicity was observed up to the highest applied concentration. In both experiments, no biologically relevant increase in the number of cells carrying structural chromosomal aberrations was observed after treatment with the test material. Appropriate mutagens were used as positive controls, which induced statistically significant increases (p < 0.05) in cells with structural chromosome aberrations. Under the specific conditions of this assay, the test material did not induce structural chromosomal aberrations as determined by the chromosome aberration test in human lymphocytes in vitro. Therefore, the test material is considered to be non-clastogenic in this chromosome aberration test in the absence and presence of metabolic activation.

All three studies presented to assess the genetic toxicity of the test material were performed in line with GLP and accepted standardised guidelines with a high standard of reporting. The studies were assigned a reliability score of 1 in accordance with the criteria for assessing data quality as outlined in Klimisch (1997) and considered suitable for assessment as an accurate reflection of the test material.

The available data are considered to be complete and the conclusion, non-mutagenic, was taken forward for risk assessment.

Justification for selection of genetic toxicity endpoint
All studies were considered together. A single study could not be selected as key; since the two Ames tests and the chromosome aberration test address different types of mutagenicity and are equally important in addressing this endpoint.

Short description of key information:
IN VITRO DATA
Reverse mutation in bacteria: Negative (S. typhimurium strains TA 1537, TA 1535, TA 100, TA 98 and TA 102 in the absence and presence of S9-mix), OECD 471, EU method B.14, Molinier 1995

Reverse mutation in bacteria: Negative (S. typhimurium strains TA 1537, TA 1535, TA 100 and TA 98 and E. coli strain WP2 uvr A in the absence and presence of S9-mix), OECD 471, EU method B.13/14, de Jouffrey 1996b

In vitro chromosome aberration: Negative, human lymphocytes with and without metabolic activation, OECD 473, EU method B.10, de Jouffrey 1996c

Endpoint Conclusion: No adverse effect observed (negative)

Justification for classification or non-classification

In accordance with criteria for classification as defined in Annex I, Regulation 1272/2008, the test material does not require classification for genetic toxicity based on the overall negative response noted in the available in vitro genetic toxicity studies.