Registration Dossier

Administrative data

Endpoint:
in vivo mammalian somatic cell study: cytogenicity / bone marrow chromosome aberration
Type of information:
experimental study
Adequacy of study:
key study
Study period:
23 February 1998
Reliability:
1 (reliable without restriction)

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1998
Report Date:
1998

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 474 (Mammalian Erythrocyte Micronucleus Test)
Version / remarks:
Adopted July 1997
Deviations:
not specified
GLP compliance:
yes (incl. certificate)
Remarks:
quality assurance statement included
Type of assay:
other: Micronucleus assay in rats

Test material

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

Test animals

Species:
rat
Strain:
Sprague-Dawley
Sex:
male/female
Details on test animals and environmental conditions:
162 g to 190 g (males) 137 g to 164 g (females), 5 to 6 weeks old
Environmental conditions: period of acclimatization of mini 5 days; ventilated rooms; temperature of 22°C and humidity of 55%; lighting 12 hours a day.

Administration / exposure

Route of administration:
oral: gavage
Vehicle:
1% Carboxymethylcellulose in distilled water
Details on exposure:
oral intubation
Frequency of treatment:
3 daily treatments
Post exposure period:
24h
Doses / concentrations
Dose / conc.:
2 000 mg/kg bw/day
Remarks:
dose administered three times
No. of animals per sex per dose:
2 males and 2 females, exposed to 3 consecutive doses in a preliminary assay, 5 males and 5 females, exposed to 3 consecutive doses of the test substance in a confirmatory assay,
Control animals:
yes
Positive control(s):
Exposed to cyclophosphamide, a clastogenic agent, at dose of 25 mg/kg (intraperitoneal route)

Examinations

Tissues and cell types examined:
Erythrocytes
Details of tissue and slide preparation:
The bone marrow is extracted from the rats femurs with foetal calf serum. The cell suspensions are centrifuged for 5 min at 1000 rpm. The supernatant is eliminated and the centrifugate is spread on slides. The smears are stained using a technique derived from the May Grunwald Giemsa technique which makes it possible to distinguish between polychromatic and normochromatic erythrocytes.
Evaluation criteria:
Ratio between normochromatic and polychromatic erythrocytes, determined by analysis of 1000 erythrocytes/animal min.
Statistics:
Statistical analysis is performed for micronucleus numbers using the Mann Whitney U rank test (non parametric test used because the distribution of the numbers of micronuclei does not correspond to a Gaussian distribution but to a Poisson-type distribution).
The statistical comparison for the polychromatic/normochromatic erythrocyte ratio and for the weight homogeneity within the sex of each group is performed using the Student's test.

Results and discussion

Test results
Key result
Sex:
male/female
Genotoxicity:
negative
Toxicity:
no effects
Remarks:
mortality endpoint only
Vehicle controls validity:
valid
Negative controls validity:
not specified
Positive controls validity:
valid
Additional information on results:
The validity criteria were fulfilled.
The minimum lethal dose of the test compound was higher than 2000 mg/kg/d (x3) by the oral route in rat. Under these conditions this dose was retained as the limit dose for the micronucleus test according to the OECD guideline recommendation.
There was no statistically significant difference between the weights of trated and control rats.

Applicant's summary and conclusion

Conclusions:
In an OECD 474 micronucleus test in male and female rats, no mortality nor clastogenic activity can be demonstrated after 3 administrations of the test substance by oral route at 2000 mg/kg/d.