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Key value for chemical safety assessment

Genetic toxicity in vivo

Description of key information
Read across to close structural analogue (CAS 16090-02-1): in vitro: Ames: negative; OECD 471 in vivo: MNT: negative; OECD 474
Link to relevant study records
Reference
Endpoint:
in vivo mammalian somatic cell study: cytogenicity / erythrocyte micronucleus
Remarks:
Type of genotoxicity: chromosome aberration
Type of information:
migrated information: read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
key study
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: OECD Guide-line study 474
Qualifier:
according to
Guideline:
OECD Guideline 474 (Mammalian Erythrocyte Micronucleus Test)
GLP compliance:
yes
Remarks:
CCR - Cytotest Cell Research GmbH & Co. KG
Type of assay:
micronucleus assay
Species:
mouse
Strain:
NMRI
Sex:
male/female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: BRL Tierfarm Fullinsdorf
- Age at study initiation: minimum 10 weeks
- Weight at study initiation: ca. 30 g
- Housing: single in Makrolon Type I cages
- Diet: pelleted standard diet (ALTROMIN, D-49 37 Lage/Lippe), ad libitum
- Water (e.g. ad libitum): tap water, ad libitum
- Acclimation period: minimum 5 days


ENVIRONMENTAL CONDITIONS
- Temperature (°C): 21 ± 3°C
- Humidity (%): 25-70%
- Photoperiod (hrs dark / hrs light): 12/12


Route of administration:
oral: gavage
Vehicle:
- Vehicle(s)/solvent(s) used: water

Duration of treatment / exposure:
24h , 48 h and 72 h
Frequency of treatment:
single application
Post exposure period:
24h , 48 h and 72 h
Remarks:
Doses / Concentrations:
5000 mg/kg bw
Basis:
actual ingested
No. of animals per sex per dose:
5
Control animals:
yes, concurrent vehicle
Positive control(s):
cyclophosphamide;
- Route of administration: orally
- Doses / concentrations: 30 mg/kg bw
Tissues and cell types examined:
polychromatic erythrocytes (PCE) in the bone marrow of the mouse
Details of tissue and slide preparation:
CRITERIA FOR DOSE SELECTION:
In a pre-experiment this dose level was estimated to be the maximum attainable dose. The animals expressed slight toxic reactions. The mean number of normochromatic erythrocytes was slightly increased after treatment with the test article as compared to the mean values of NCEs of the corresponding negative controls, indicating that the test substance had weak cytotoxic properties.
Evaluation criteria:
A test article is classified as mutagenic if it induces a statistically significant increase in the number of micronucleated polychromatic erythrocytes at for at least one of the test points. A test article producing no statistically significant increase in the number of micronucleated polychromatic erythrocytes at anyone of the test points is considered non-mutagenic in this system.
Statistics:
nonparametric Mann-Whitney test
Sex:
male/female
Genotoxicity:
negative
Toxicity:
yes
Remarks:
the concentration used was slightly cytotoxic.
Vehicle controls validity:
valid
Negative controls validity:
valid
Positive controls validity:
valid
In comparison to the corresponding negative controls there was no significant enhancement in the frequency of the detected micronuclei at any preparation interval after administration of the test item. The mean values of micronuclei observed in treated animals (0.09%, 0.10% and 0.09% at 24, 48 and 72 hours, respectively) were similar to those of the negative controls (0.06%, 0.07% and 0.06%, respectively). The mean numbers of NCE per 1000 PCE were slightly increased in the treated animals compared to the controls (976, 1028 and 927 in treated and 829, 888 and 769 in the controls at 24, 48 and 72 hours, respectively), indicating that the concentration used was slightly cytotoxic. The test was valid, since the positive control caused a distinct increase in the frequency of micronuclei 0.63 % vs. 0.06% in the negative control).

In conclusion, it can be stated that during the study described and under the experimental conditions reported, the test article did not induce micronuclei as determined by the micronucleus test with bone marrow cells of the mouse. Therefore, the test substance is considered to be non-mutagenic in this micronucleus assay.

Conclusions:
Interpretation of results (migrated information): negative
The test substance did not induce micronuclei in bone marrow cells of the mouse.
Endpoint conclusion
Endpoint conclusion:
no adverse effect observed (negative)

Additional information

Additional information from genetic toxicity in vivo:

In vitro data:

Mutagenicity in bacterial reverse mutation assays (Ames test) has been investigated with a close structural analogue (CAS 16090 -02 -1). Negative results were obtained with and without metabolic activation. Relevant tester stains were tested and test item concentrations were adequate.

In vivo data:

Induction of micronuclei in vivo was investigated in a study with mice which were orally treated with a close structural analogue (CAS 16090 -02 -1) at doses of 5000 mg/kb bw: No increase in the number of micronuclei were observed. No toxic effects were observed. Conclusions: Possible mutagenic potential of the substance has been investigated in vitro (bacterial reverse mutation assays-Ames tests) as well as in vivo (micronucleus assay in mice). All these tests consistently yielded negative results indicating that the substance has no mutagenic potential. It is concluded that these negative findings can also be transferred to the the substance CAS 133 -66 -4.

Justification for classification or non-classification

Dangerous Substance Directive (67/548/EEC)

The available studies are considered reliable and suitable for classification purposes under 67/548/EEC. As a result the substance is not considered to be classified for genetic toxicity under Directive 67/548/EEC, as amended for the 28th time in Directive 2001/59/EC.

 

Classification, Labelling, and Packaging Regulation (EC) No. 1272/2008

The available experimental test data are reliable and suitable for classification purposes under Regulation 1272/2008. As a result the substance is not considered to be classified for genetic toxicity under Regulation (EC) No. 1272/2008.