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Key value for chemical safety assessment

Additional information

A bacterial reverse mutation assay with S. typhimurium was conducted using AD-Cyanhydrin concentrations from 25 to 1000 µg per plate. AD-Cyanhydrin was examined for mutagenic activity in the five histidine-dependent Salmonella typhimurium strains TA 1535, TA 100, TA 1537, TA 1538 and TA 98 with and without metabolic activation. Growth inhibition could be observed on TA 1535, TA 1537 and TA 1538 starting at 500 µg/plate and on TA 98 at 1000 µg/plate without S9-mix. Precipitates in the agar were found at least in the highest concentration

There was no evidence for a mutagenic activity of AD-Cyanhydrin, when tested up to the dose level of 1000 µg/plate in the absence and presence of S9 mix.

For assessment of the clastogenic potential of AD-Cyanhydrin (= ZK 74.804) a chromosome aberration test in vitro was conducted in human peripheral blood lymphocytes. The cells were treated with 5, 10 and 25 µg/ml AD-Cyanhydrin without S9 mix and with 10, 50 and 100 µg/ml with S) mix. In both assays ZK 74.804 was clearly cytotoxic at the highest concentration as proven by the reduction of the mitotic index and neither assay showed an increase in structural chromosomal aberrations in the cultures treated with ZK 74.804 as compared with the negative controls.

Based on this, AD-Cyanhydrin showed no clastogenic potential in human lymphocytes in vitro with and without metabolic activation.

Additionally, a mouse micronucleus test was conducted to investigate the potential of AD-Cyanhydrin (= ZK 74.804) to induce chromosome breakage or malfunction of the spindle apparatus. Male and female NMRI mice were treated once by gavage with 1.0, 2.5 or 5.0 g/kg body weight. Control animals were given the vehicle at 40 ml/kg in the same manner. Triaziquone (0.15 mg/kg; single i.p. treatment) served as positive control. Animals of the control and treatment groups were killed at intervals of 24, 48 and 72 hours after treatment. The positive control animals were killed 24 hours after treatment. Femur bone marrow smears were prepared and stained using May-Gruenwald and Giemsa solutions. The coded slides were examined for the presence of micronuclei in 1000 polychromatic and 1000 normochromatic erythrocytes and for the ratio of polychromatic to normochromatic erythrocytes. The micronucleated cell counts obtained with ZK 74.804 were comparable with the concurrent control values. No bone marrow depression was observed.

Therefore, AD-Cyanhydrin showed no mutagenic potential when administered by gavage up to 5 g/kg in the mouse micronucleus test.


Short description of key information:
Gene mutation in vitro (bacterial reverse mutation assay, GLP, comparable to OECD TG 471): negative in the Salmonella typhimurium strains TA 1535, TA 1537, TA 100, TA 1538 and TA 98 with and without S9 mix
[Schering AG, Report No. 6534, 1985-04-03]

Chromosome aberration in vitro (human lymphocytes, GLP, comparable to OECD TG 473): negative with and without S9 mix
[Schering AG, Report No. 7244/J, 1986-06-25]

Chromosome aberration in vivo (mouse micronucleus test, GLP, comparable to OECD TG 474): negative
[Schering AG, Report No. 7288, 1986-09-05]

Endpoint Conclusion: No adverse effect observed (negative)

Justification for classification or non-classification

Based on the study results a classification according to Directive 67/548/EEC and Regulation (EC) No. 1272/2008 (CLP) is not required.