Registration Dossier

Toxicological information

Genetic toxicity: in vivo

Currently viewing:

Some information in this page has been claimed confidential.

Administrative data

Endpoint:
in vivo mammalian somatic cell study: cytogenicity / erythrocyte micronucleus
Type of information:
experimental study
Adequacy of study:
weight of evidence
Study period:
From November 12, 1999 to December 04, 1999
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1999
Report Date:
1999

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
OECD Guideline 474 (Mammalian Erythrocyte Micronucleus Test)
Deviations:
no
Qualifier:
according to
Guideline:
EU Method B.12 (Mutagenicity - In Vivo Mammalian Erythrocyte Micronucleus Test)
Deviations:
no
Qualifier:
according to
Guideline:
EPA OPPTS 870.5395 (In Vivo Mammalian Cytogenetics Tests: Erythrocyte Micronucleus Assay)
Deviations:
no
GLP compliance:
yes
Type of assay:
other: Mammalian Erythrocyte Micronucleus test

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
solid: particulate/powder
Remarks:
red powder
Specific details on test material used for the study:
Purity: 52%
Suspension: in deionized water

Test animals

Species:
mouse
Strain:
NMRI
Sex:
male/female
Details on test animals and environmental conditions:
Origin: Harlan Winkelmann GmbH
Acclimatization: at least 5 days
Body weight (mean): 24.0 and 34.2 g (female and male)
Age: ca. 7 weeks
Temperature and relative humidity: 20+/-3°C and 50+/-20%, respectively
Lighting time: 12 h daily
Food: ssniff R/M-H (V 1534), ad libitum
Water: tap water, ad libitum

Administration / exposure

Route of administration:
oral: gavage
Vehicle:
deionized water
Details on exposure:
Twice at an interval of 24 h
Dose: 2000 mg/kg bw (based on a preliminary study)
Sacrifice: 24 h after administration
Duration of treatment / exposure:
24 h
Frequency of treatment:
Twice
Post exposure period:
24 h
Doses / concentrations
Dose / conc.:
2 000 mg/kg bw/day (actual dose received)
Remarks:
volume: 10 mL/kg bw
No. of animals per sex per dose:
5
Control animals:
yes, concurrent vehicle
Positive control(s):
Yes: Endoxan (cyclophosphamide), 50 mg/kg bw administered once orally

Examinations

Tissues and cell types examined:
Bone marrow from the femora
Erythrocytes
Details of tissue and slide preparation:
A part of the suspension was smeared onto a cleaned slide and air-dried for about 12 h. The staining was performed as follows:
5 min in methanol, 5 min in May-Grünwald's solution, brief rinsing in distilled water, 10 min in Giemsa/buffer solution, rinsing in distilled water, drying and coating with Entellan
Evaluation criteria:
Validity assessment and mutagenicity:
2000 polychromatic erythrocytes were counted for each animal. The number of cells with micronuclei was recorded, not the number of individual micronuclei. In addition, the ratio (proportion) of polychromatic erythrocytes to 200 total erythrocytes was determined.
Statistics:
One-sided Wilcoxon test
(Both biological and statistical significances)
A substance is considered positive if there is a significant increase in the number of micronucleated polychromatic erythrocytes compared with the concurrent negative control group.

Results and discussion

Test results
Key result
Sex:
male/female
Genotoxicity:
negative
Toxicity:
no effects
Vehicle controls validity:
valid
Negative controls validity:
valid
Positive controls validity:
valid
Additional information on results:
The number of polychromatic erythrocytes containing micronuclei was not increased. The ratio of polychromatic erythrocytes to total erythrocytes in both male and female animals remained unaffected by the treatment with the test substance and was not less than 20% of the control value.
Positive control (endoxan): induction of a marked statistically significant increase in the number of polychromatic cells with micronuclei. The ratio of polychromatic erythrocytes to total erythrocytes was not changed to a significant extent.
All animals survived after treatment. No signs of toxicity were observed. The following clinical signs were recorded: red colored urine and faeces.

Applicant's summary and conclusion

Conclusions:
Under the study conditions, the test substance did not lead to a substantial increase of micronucleated polychromatic erythrocytes and was not mutagenic in the micronucleus test.
Executive summary:

A study was conducted to determine the in vivo clastogenic potential of the substance according to OECD Guideline 474, EU Method B12 and US EPA OPPTS 870.5395, in compliance with GLP. Male and female NMRI mice received the test substance by oral gavage at a concentration of 0 (vehicle alone) or 2000 mg/ kg bw twice at an interval of 24 h. Positive control mice received cyclophosphamide at 50 mg/kg bw. Bone marrow erythrocytes from the femora were analysed. 2000 polychromatic erythrocytes were counted per animal for the presence of micronuclei. In addition, the ratio of polychromatic erythrocytes to 200 total erythrocytes was determined. As a result of the test substance exposure, the number of polychromatic erythrocytes containing micronuclei was not increased. The ratio of polychromatic erythrocytes to total erythrocytes in both male and female animals remained unaffected by the treatment with the test substance and was not less than 20% of the control value. The positive control group showed a statistically significant increase in the number of polychromatic cells with micronuclei. All animals survived the treatment and no signs of toxicity were observed. Under the study conditions, the substance did not lead to a substantial increase of micronucleated polychromatic erythrocytes and was not clastogenic in the micronucleus test (Stammberger, 1999).