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Toxicological information

Genetic toxicity: in vitro

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Administrative data

Endpoint:
in vitro cytogenicity / chromosome aberration study in mammalian cells
Remarks:
Type of genotoxicity: chromosome aberration
Type of information:
experimental study
Adequacy of study:
key study
Study period:
April - October 1992
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1992
Report Date:
1992

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
OECD Guideline 473 (In Vitro Mammalian Chromosome Aberration Test)
Qualifier:
according to
Guideline:
EPA OTS 798.5375 (In Vitro Mammalian Chromosome Aberration)
Qualifier:
according to
Guideline:
EU Method B.10 (Mutagenicity - In Vitro Mammalian Chromosome Aberration Test)
Qualifier:
according to
Guideline:
JAPAN: Guidelines for Screening Mutagenicity Testing Of Chemicals
GLP compliance:
yes
Remarks:
This study has been performed in compliance with GLP in Switzerland, Procedures and Principles, March 1986, issued by the Swiss federal Department of the Interior and the Intercantonal Office for the Control of Medicaments.
Type of assay:
in vitro mammalian chromosome aberration test

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
solid: bulk

Method

Target gene:
not applicable, examination of metaphase cells for the presence of structural chromosome aberrations
Species / strain
Species / strain / cell type:
Chinese hamster Ovary (CHO)
Details on mammalian cell type (if applicable):
- Cell line: CHO CCL 61
- Type and identity of media: supplemented nutrient mixture F-12
- Properly maintained: yes
- Periodically checked for Mycoplasma contamination: yes
Metabolic activation:
with and without
Metabolic activation system:
Post mitochondrial fraction S9 from Aroclor 1254 induced rat liver.
Test concentrations with justification for top dose:
- Original study, first experiment, without metabolic activation: 8 concentrations, range: 25.78 - 3300 µg/ml
- Original study, second experiment, with metabolic activation: 8 concentrations, range: 25.78 - 3300 µg/ml
- Confirmatory study, first experiment, without metabolic activation: 5 concentrations, range: 25.78 - 412.5 µg/ml
- Confirmatory study, second experiment, with metabolic activation: 5 concentrations, range: 103.13 - 1650 µg/ml
- Confirmatory study, third experiment, without metabolic activation: 10 concentrations, range: 6.45 - 3300 µg/ml
- Confirmatory study, fourth experiment, with metabolic activation: 8 concentrations, range: 25.78 - 3300 µg/ml
Controlsopen allclose all
Untreated negative controls:
yes
Remarks:
two in each experiment: one supplemented with vehicle, one without any additions
Negative solvent / vehicle controls:
no
True negative controls:
no
Positive controls:
yes
Positive control substance:
cyclophosphamide
Remarks:
Migrated to IUCLID6: ASTA-Werke, Germany, 20 µg/ml; with S9
Untreated negative controls:
yes
Remarks:
two in each experiment: one supplemented with vehicle, one without any additions
Negative solvent / vehicle controls:
no
True negative controls:
no
Positive controls:
yes
Positive control substance:
mitomycin C
Remarks:
Migrated to IUCLID6: KYOWA HAKKO KOGYO Ltd., Japan, 0.2 µg/ml; without S9

Results and discussion

Test results
Key result
Species / strain:
Chinese hamster Ovary (CHO)
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
cytotoxicity
Remarks:
experiments without S9: cytotoxicity with final concentrations > 412.5 or 206.5 µg/ml of culture medium, cytotoxicity; experiments with S9: cytotoxicity with final concentrations > 1650 µg/ml of culture medium
Vehicle controls validity:
not applicable

Applicant's summary and conclusion

Conclusions:
Interpretation of results:
negative

It is concluded that under the given experimental conditions no evidence of clastogenic effects was obtained in Chinese hamster ovary cells in vitro treated with CA 1139 A.
Executive summary:

CA 1139 A (Intermediate of CGA 219417), identified as a light beige crystalline powder, 76.2 % purity, batch no. P.201025, was investigated for clastogenic (chromosome-damaging) effects on Chinese Hamster ovary cells in vitro with and without extrinsic metabolic activation (S9). The compound was dissolved in culture medium (without metabolic activation) or in nutrient mixture F-12 (with metabolic activation) and tested at each of the following conditions:

 

Experiment without metabolic activation:

- 18 hours treatment time:

original experiment: 103.13, 206.25 and 412.5 µg/ml

confirmatory experiment: 103.13, 206.25 and 412.5 µg/ml

- 42 hours incubation time: 51.56, 103.13 and 206.65 µg/ml

Final concentrations higher than 412.5 or 206.65 µg/ml of culture medium could not be scored due to cytotoxicity. Cytotoxicity was observed at concentrations of 412.5 µg/ml and higher. Mitomycin C (0.2 µg/ml) was used as a positive control in the 18 hours experiments.

 

Experiment with metabolic activation:

- 3 hours treatment followed by 15 hours recovery period:

original experiment: 412.5, 825 and 1650 µg/ml;

confirmatory experiment: 412.5, 825 and 1650 µg/ml.

- 3 hours incubation followed by 39 hours recovery period: 825, 1650 and 3300 µg/ml.

Final concentrations greater than 3300 µg/ml of culture medium could not be achieved due to solubility limitations. In the 3h/15h experiments, concentrations greater than 1650 µg/ml of culture medium could not be scored due to cytotoxicity. Cyclophosphamide (20.0 µg/ml) was used as a positive control in the 3h/15h experiments.

 

In both the experiments performed according to OECD Guideline 473 without and with metabolic activation CA 1139 A did not induce a biologically significant increase in the number of metaphases containing specific chromosomal aberrations.