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Administrative data

Key value for chemical safety assessment

Additional information

Ames test

In 2012, Nigrosin was initially investigated in the Ames test according to OECD TG 471 and GLP using the Salmonella typhimurium TA 98, TA100, TA102, TA1535, TA1537 and concentrations up to and including 5000 µg/plate. Bacteriotoxicity was not reached. None of the 5 strains used showed a dose-related and biologically relevant increasein mutant counts over those of the negative controlsneither in the presence nor in the absence of the metabolic activation system S9 -mix. The positve controls were functional.

Due to these results Nigrosin WLF has to be regarded as non-mutagenic . Thus, the result of an Ames test, performed in 1990 was conformed which was carried out according to the respective Guideline using only 4 strains of Salmonella typhimurium.

HPRT-test

The study was performed to investigate the potential of Nigrosin WLF to induce gene mutations at the HPRT locus in V79 cells of the Chinese hamster according to OECD TG 476. 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 dose-range of the main experiments was limited by cytotoxic effects; no precipitation of the test item at the end of treatment was noted. No substantial and reproducible dose dependent increase of the mutation frequency was observed in both main experiments.

Appropriate reference mutagens, 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. Therefore, 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. Thus, Nigrosin WLF is considered to be non-mutagenic in this HPRT assay.

MNT in vitro

Nigrosin WLF was examined for mutagenic activity in the micronucleus test in vitro according to OECD TG 487 in the presense and in th absence of a metabolic activation system..No cytotoxic effects were observed. in the 4 hour treatment with and without S9- mix up to 200 µg/ml or during 24 hour treatment in the absence of S9 -mix up to 500 µg/ml. Precipitation in the medium could be observed at 50 µg/ml and above without S9 -mix and at 200 µg/ml in the presence of S9 -mix. No biologically relevant increase in the frequencies of micronucleus containing V79 cells treated with the test item in the absence (4 hours or 24 hours treatment) or in the presence of S9 mix.were seen. Evaluation of the data does not indicate that Nigrosin WLF is a mutagen in the micronucleus test in vitro in the absence or presence of metabolic activation.

Overall conclusion

Nigrosin WLF was tested for mutagenicity using the Ames test, the HPRT test and the micronucleus test in vitro. In none of these tests Nigrosine WLF revealed mutagenic activity. Thus it can be concluded that Nigrosin WLF is not mutagen and not clastogen..


Justification for selection of genetic toxicity endpoint
No study was selected because all three in vitro key studies and the supporting study were negative-
The substance is not mutagenic.
Overall conclusion, the substance is not mutagenic

Short description of key information:
Nigrosin WLF was tested for mutagenicity using the Ames test, the HPRT test and the micronucleus test in vitro. In none of these tests Nigrosine WLF revealed mutagenic activity. Thus it can be concluded that Nigrosin WLF is not mutagen and not clastogen.

Endpoint Conclusion: No adverse effect observed (negative)

Justification for classification or non-classification

Based on the available data no classification or labelling with respect to mutagenicity is required.