Disodium 4,4'-bis[(4-anilino-6-morpholino-1,3,5-triazin-2-yl)amino]stilbene-2,2'-disulphonate

Endpoint summary

Additional information

The test substance was assessed for its potential to induce point mutations according to the OECD guideline 471, using Salmonella typhimurium strains TA 1535, TA 1537, TA 1538, TA 98 and TA 100. Up to the highest investigated dose (5000 µg/plate), neither a significant and reproducible increase of the number of revertants was found. In strain TA 98 a slight increase in revertant colony numbers was observed at 5000 µg/plate in the presence of metabolic activation, in the experiment II. This effect is considered being irrelevant since it could not be reproduced in the independent experiment, therefore it can be stated that during the described mutagenicity experiment the test article did not induce point mutations by base pair changes or frameshifts in the genome of the strains used (CCR Cytotest Cell Research GmbH & Co. KG, 1991).

In order to detect cross-linking mutagens, the OECD 471 recommends to include in the assessment the TA102 strain or to add a DNA repair-proficient strain of E.coli [e.g. E.coli WP2 or E.coli WP2 (pKM101)], therefore a further study was performed (BASF SE, 2015).

All the further supporting studies confirm the results of the key studies.

The test substance was also assayed for the mutagenicity by the In Vitro Mammalian Cell Gene Mutation Test. The performed test was based on the OECD Test Guideline No. 476.V79 hamster fibroblast were used for testing. The test substance was dissolved in dimethyl sulfoxid (DMSO) and the test concentration were 0.1; 0.25; 0.5 and 1.0 mg/ml. Each concentration was tested in two replicates. Experiments were performed without as well as with of metabolic activation using the supernatant of rat liver and a mixture of cofactors. A preliminary cytotoxicity assay (3-hour treatment) was performed at first. The test substance was assayed at a maximum possible concentration in DMSO that is 1 mg/ml. In this maximum concentration – about 46 % of survival was observed in experiment with metabolic activation and 61 % without metabolic activation.

First experiment (3 hour treatment) with the test substance followed then. Four concentrations were used - the maximum concentration 1.0 mg/ml and three lower concentrations, 0.5; 0.25 and 0.1 mg/ml. The test was performed with as well as without metabolic activation.

Results of first experiment were negative, so the modification of experiment was performed with extended treatment time of 24 hours and lower concentrations considering toxicity of the test substance shown in cytotoxicity experiment (0.1; 0.2; 0.33 and 0.5 mg/ml). The test was performed without metabolic activation only; each concentration was tested in replicate. Also the second experiment gives no evidence of the mutagenicity of test substance (Research Institute for Organic Syntheses Inc. CETA, 2014).

Clastogenicity in mammalian cells was investigated testing the substance to be registered (CAS 16090-02-1) in the Chinese hamster lung fibroblasts (V79), in absence and the presence of metabolic activation by rat liver S-9 mix, according to the procedures outlined into the OECD guideline 473. Both, in the absence and presence of S9 mix the test article did not increase the frequency of cells with aberrations at any fixation interval. The aberration rates of the cells after treatment with the test article (0.0% - 2.0%) were in or near to the range of the control values (Cytotest Cell Research GmbH & Co. KG, 1991).

The further studies available were performed in vivo assessing the potential of the CAS 16090-02-1 to induce a chromosomal aberration.

Both the Micronucleus assay in bone marrow cells (Cytotest Cell Research GmbH & Co. KG, 1991) and the Nucleus anomaly test on somatic interphase nuclei (Ciba Geigy Ltd., 1994) did not recorded any evidence of mutagenicity in bone marrow cells of the mouse and in Chinese hamster treated, respectively.

The Chromosome study on somatic cells of Chinese Hamster was performed to evaluate any mutagenic effect on the somatic cells in vivo as expressed by chromatid-type and chromosome-type aberrations. The chromosome displays from the animals of the control group and of the dosage groups showed no chromatid-type or chromosome-type aberrations (Ciba Geigy Ltd., 1974).

Finally, also in the dominant lethal assay test the females mated to males, which were treated with the compound did not differ from the females mated to controls, neither in mating ratio nor in the number of implantations and embryonic deaths (resorptions), thus no evidence of dominant lethal effect was observed in the progeny of male mice treated (Ciba Geigy Ltd., 1974).

Justification for selection of genetic toxicity endpoint

Evaluation of the endpoint has been performed with the integrated evaluation of the following studies: in vitro Ames tests (CCR Cytotest Cell Research GmbH & Co. KG, 1991 and BASF SE, 2015), in vitro gene mutation on mammalian cells (Research Institute for Organic Syntheses Inc. CETA., 2014) and in vivo chromosomal aberration (Ciba-Geigy Ltd., 1974).

Short description of key information:

Non genotoxic

Endpoint Conclusion: No adverse effect observed (negative)

Justification for classification or non-classification

According to the CLP Regulation (EC 1272/2008), 3.5 Germ cell mutagenicity section, a mutation means a permanent change in the amount or structure of the genetic material in a cell. The term ‘mutation’ applies both to heritable genetic changes that may be manifested at the phenotypic level and to the underlying DNA modifications when known (including specific base pair changes and chromosomal trans locations). The term ‘mutagenic’ and ‘mutagen’ will be used for agents giving rise to an increased occurrence of mutations in population of cells and/or organisms.

The test substance did not show any reasons of concern in the test performed.

In conclusion, the available experimental data are adequate for classification and labelling and the substance is not classified for genetic toxicity according to the CLP Regulation (EC 1272/2008).