methyl 5-(bis(methoxycarbonylmethylamino))-4-cyano-3-methoxycarbonylmethylthiophen-2-carboxylate

Genetic toxicity: in vivo

Administrative data

Endpoint:

in vivo mammalian somatic cell study: cytogenicity / erythrocyte micronucleus

Remarks:

Type of genotoxicity: chromosome aberration

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2004

Reliability:

1 (reliable without restriction)

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2004

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 474 (Mammalian Erythrocyte Micronucleus Test)

GLP compliance:

yes (incl. QA statement)

Type of assay:

micronucleus assay

Test material

Reference

Name:

Unnamed

Type:

Constituent

Test animals

Species:

mouse

Strain:

Swiss

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Breeder: Charles River Laboratories, l'Arbresle, France.
- Age at study initiation: approximately 6 weeks
- Weight at study initiation: males: 28 - 33 g; females 21 - 27 g
- Assigned to test groups randomly: yes, the animals were randomly allocated to the groups by sex
- Fasting period before study: no.
- Housing: by groups in polycarbonate cages;
bedding: autoclaved sawdust (SICSA, Alfortville, France)
- Diet (ad libitum): Ssniff R/M-H pelleted maintenance diet (SSNIFF Spezialdiäten GmbH, Soest, Germany).
- Water (ad libitum): drinking water filtered by a FG Millipore membrane (0.22 micron)
- Acclimation period: at least 5 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22 ± 2°C,
- Humidity (%): 30 - 70%
- Air changes (per hr): 12 cycles/hour of filtered non-recycled fresh air
- Photoperiod (hrs dark / hrs light): 12 h/12 h (07:00 - 19:00)

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

Vehicle
Name: 0.5% methylcellulose

Positive controls
The positive control was Cyclophosphamide 50 mg/kg.

Details on exposure:

For the vehicle and the test item:
• Route: oral, since it is a possible route of exposure in Man
• Frequency: two treatments separated by 24 hours
• Volume: 10 mL/kg.

For the positive control (CPA):
• Route: oral
• Frequency: one treatment
• Volume: 10 mL/kg.

Duration of treatment / exposure:

48 hours (test item)
24 hours (cyclophosphamide)

Frequency of treatment:

two treatments separated by 24 hours

Post exposure period:

24 hours

No. of animals per sex per dose:

Doses/concentrations:
Test item
males: 250-500-1000 mg/kg
females: 125-250-500 mg/kg
CPA = 50 mg/kg.

5males and 5 females/doses including controls except 8 males and 8 females at the high dose level.

Control animals:

yes, concurrent vehicle

Positive control(s):

cyclophosphamide

Examinations

Tissues and cell types examined:

Femoral bone marrow.
Erythrocyte cell line.

Details of tissue and slide preparation:

Bone marrow flushed out with fetal colf serum. Centrifugation and straining cell suspension spread on the slide.

Evaluation criteria:

Straining with Giensa.
- 2000 polychromate erythocytes evaluated/animal for MPE.
- PE/NE ratio: 100 erythrocytes.

Statistics:

Yes.
Statistically significant increase in the MPE frequency versus controls.
-historical date and biological relevance also considered.

Results and discussion

Test results

Test results 1

Sex:

male

Genotoxicity:

negative

Toxicity:

yes

Remarks:

One mortality at 1000-L. No effect on PE/NE.

Vehicle controls validity:

valid

Negative controls validity:

not examined

Positive controls validity:

valid

Test results 2

Sex:

female

Genotoxicity:

negative

Toxicity:

no effects

Remarks:

125, 250 and 500 mg/kg/day

Vehicle controls validity:

valid

Negative controls validity:

not examined

Positive controls validity:

valid

Applicant's summary and conclusion

Conclusions:

Interpretation of results (migrated information): negative
No clastogenic potential in the mouse up to 2000 mg/kg.