Registration Dossier

Administrative data

Key value for chemical safety assessment

Genetic toxicity in vitro

Description of key information

negative induction of mutation frequence

Endpoint conclusion
Endpoint conclusion:
no adverse effect observed (negative)

Genetic toxicity in vivo

Endpoint conclusion
Endpoint conclusion:
no adverse effect observed (negative)

Additional information

The following data is obtained for Similar Substance 02. It is expected that Target substance will present similar genetic toxicity profile. Justification for Read Across is given in Section 13 of IUCLID.

 

Gene mutation in bacteria

The first study was made in 1993 and conducted according to OECD guideline 471 (tested up to 5000 μg/plate with Salmonella typhimurium TA1535, TA1537, TA98 and TA100; a bacteriotoxic effect was not observed but a precipitation of the test substance between 100 and 5000 µg/plate. Precipitation correlated with mutagenic activity. The results indicated that an impurity of the test material could have been responsible for the genotoxic effect.

 

The second test was made in 1983 according to OECD guideline 471 guideline with dose range 0, 20, 100, 500, 2500 and 5000 µg/plate. The test substance gave positive results for strains TA1535, TA1537, TA98 and TA100 of Salmonella typhimurium from concentration 100 µg upward with an without metabolic activation.

The test substance showed a strain-dependent weak to moderate mutagenic effect without metabolic activation from 2500 µg/plate onward. In presence of metabolic activation no mutagenic effect was observed for TA1535, TA1538 and TA98 and a weak mutagenic effect for TA100 and TA1537 (>2500 µg/plate).

 

The third study was made in 1986. The intrasanguineous host-mediated assay (IHMA) employs microbial indicator cells to assay for mutagens using the intact animal as the source of chemical transformation, detoxification, systemic distribution, and excretion. By intrasanguineous injection of the bacteria strains Salmonella typhimurium TA1535, TA98 and TA100, the indicator organisms were brought into close contact with the mammalian metabolic organ(s). Subsequent recovery and plating of the cells for mutations might indicate the ultimate mutagenic metabolites of a test material within the animal body.

The test material did not exhibit genetic activity in the host mediated assay using the strains TA100, TA98 and TA1535 of Salmonella typhimurium injection into mice and was considered inactive under the test conditions employed, according to our evaluation criteria.

 

Gene mutation in mammalian cells

The potential of the test substance to induce gene mutations at the HGPRT locus using chinese hamster ovary cells was tested in vitro with and without metabolic activation according to OECD guideline 476 (tested up to 3420 μg/ml). Cytotoxicity was observed in an intermediate concentration range around 20 µg/ml of test substance, presumably induced by inhibition of enzymes of the S9-mix. The test substance showed no mutagenic effects on the HGPRT locus of CHO cells.

 

Cytogenicity in vivo

The potential of the test substance to induce chromosome damage or spindle poisoning was investigated in an OECD guideline 474 conform standard micronucleus test study in male and female NMRI mice. Test substance was given orally in CMC-vehicle in concentrations of 1700,3400 and 6800 mg/kg bw (>limit dose tested in acute oral toxicity study) and bone marrow was isolated after 16,24 and 48 h. No signs of toxicity and no pathological changes of the organs were observed in any dose groups. Microscopic evaluation of bone-marrow derived erythrocytes showed that the test substance did not impair erythropoeisis, did not induce any chromosome-damaging (clastogenic) effects and did not impair chromosome distribution in the course of mitosis.

 

A second in vivo rat hepatocyte UDS indicator test was done according to OECD guideline 486. The test material was administered in water orally to rats (4000,2000,1000 and 500 mg/kg bw) and 4 h later hepatocytes were isolated, labelled with 3H-thymidine, processed and net nuclear grains were determined via microscopic evaluation. The test substance did not induce nuclear staining differently from vehicle control levels and no dose-related trend was observed, thus, the test material was inactive in the UDS-test in the dose range tested.

Justification for classification or non-classification

The test substance showed genotoxic reactions only in in vitro experiments using bacteria (Ames test). In all other experiments using bacteria in vivo (host mediated assay), mammalian cells in vitro (CHO, hamster; HGPRT test), mammalian cells in a combined in vitro/in vivo study (UDS test) or whole animals (in vivo micronucleus test) the test substance did not exhibit any genetic activity.

Therefore, based on the information currently available, there is no need for classification of the test substance for mutagenic effects under the CLP Regulation (EC 1272/2008).