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Toxicological information

Genetic toxicity: in vivo

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Administrative data

Endpoint:
in vivo mammalian somatic cell study: cytogenicity / bone marrow chromosome aberration
Remarks:
Type of genotoxicity: chromosome aberration
Type of information:
experimental study
Adequacy of study:
key study
Study period:
26 June 2007 to 24 August 2007
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Study conducted under GLP conditions

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2007
Report date:
2007

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to guideline
Guideline:
OECD Guideline 475 (Mammalian Bone Marrow Chromosome Aberration Test)
Deviations:
yes
Remarks:
1: For three animals of the positive control groups seven slides were prepared per animal. 2: Only 4 high dose female slides were prepared. The study integrity was not adversely affected by the deviations
Qualifier:
according to guideline
Guideline:
other: EEC Directive 2000/32/EC, Part B: Methods for the Determination of Toxicity, B. 11: "Mutagenicity: In Vivo Mammalian Bone Marrow Chromosome Aberration Test"
Deviations:
yes
Remarks:
1: For three animals of the positive control groups seven slides were prepared per animal. 2: Only 4 high dose female slides were prepared. The study integrity was not adversely affected by the deviations
GLP compliance:
yes
Type of assay:
other: Rat bone marrow cytogenetic assay

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
other: liquid
Details on test material:
- Name of test material (as cited in study report): MTDID 6675
- Substance type: Clear colourless liquid
- Physical state: Liquid
- Analytical purity: Formulation tested is 30.0% active ingredient in water
- Purity test date: 12/20/2005
- Lot/batch no.: 140499-19/10
- Expiration date of the lot/batch:01 December 2008
- Storage condition of test material: Refrigerated (2-8 degrees C) in the dark

Test animals

Species:
rat
Strain:
other: Wistar WI rats (SPF)
Sex:
male/female
Details on test animals or test system and environmental conditions:
TEST ANIMALS
- Source: Charles River, Sulzfeld, Germany
- Age at study initiation: 8 weeks old
- Weight at study initiation: Females: 181.8-188.4 grams, Males: 253.4-273.2 grams
- Assigned to test groups randomly: Yes
- Fasting period before study: No data
- Housing: Five animals per group were group-housed in labeled polycarbonate cages (type MIV height: 18 cm) containing sterilised sawdust as bedding material.
- Acclimation period: At least 5 days.
ENVIRONMENTAL CONDITIONS
- Temperature (°C): 21.5-22.9
- Humidity (%): 41-78
- Air changes (per hr): 15
- Photoperiod (hrs dark / hrs light): 12/12

Administration / exposure

Route of administration:
oral: gavage
Vehicle:
Vehicle(s)/solvent(s) used: None
Details on exposure:
PREPARATION OF DOSING SOLUTIONS:
TEST MATERIAL
- Amount(s) applied (volume or weight with unit): Male Doses: 1120, 560, and 280 mg test material/ kg body weight. Females: 940, 470, and 235 mg test material/kg body weight.
- Concentration (if solution): Test material was supplied as 30% active ingredient in water.
- Constant volume or concentration used: yes, dosed as recieved
Duration of treatment / exposure:
Single oral gavage dose was administered to each animal.
Frequency of treatment:
Single dose was administered.
Post exposure period:
The first sampling time was 12-18 hours after treatement and the second sampling time was 36-44 hours after treatment.
Doses / concentrations
Remarks:
Doses / Concentrations:
Male Doses: 1120, 560, and 280 mg test material/ kg body weight. Females: 940, 470, and 235 mg test material/kg body weight.
Basis:
actual ingested
No. of animals per sex per dose:
1-3
Control animals:
yes, sham-exposed
Positive control(s):
Positive control substance: Cyclophosphamide (CP; CAS no. 50-18-0; Endoxan, Asta-Werke, Germany) dissolved in physiological saline, dosed as a single oral intubation of 20 and 40 mg/kg body weight.
- Route of administration: Oral gavage
- Doses / concentrations: 20 and 40 mg/kg body weight.

Examinations

Tissues and cell types examined:
Bone marrow isolated from the femurs was suspended in 4 ml of Hank's Balanced Salt Solution. The suspension was centrifuged at 1000 rpm for 5 minutes. Cells in the pellet were swollen by a 15 min treatment with hypotonic solution of 0.56% potassium chloride. Cells were fixed with 3 changes of methanol:acetic acid fixative (3:1, v/v).
Details of tissue and slide preparation:
CRITERIA FOR DOSE SELECTION: Dose range finding study was conducted.
TREATMENT AND SAMPLING TIMES: The first sampling time was 12-18 hours after treatement and the second sampling time was 36-44 hours after treatment.
DETAILS OF SLIDE PREPARATION: Slides were stained with 5% (v/v) Giemsa solution in tap water.
METHOD OF ANALYSIS: The mitotic index of bone marrow metaphase slides was determined by counting the number of metaphases per 1000 cells per animal.

Results and discussion

Test results
Sex:
male/female
Genotoxicity:
negative
Vehicle controls validity:
valid
Negative controls validity:
valid
Positive controls validity:
valid

Applicant's summary and conclusion

Conclusions:
Interpretation of results (migrated information): negative
Based on the results of this study, test article does not disturb mitotic processes and cell cycle progression and does not induce numerical chromosome aberrations under the experimental study conditions.
Executive summary:

The objective of this study was to evaluate the potential of the test article to cause chromosomal aberrations in vivo according to the methods described in OECD Guideline 475 and EEC Directive 2000/32/EC, Part B. Five male and five female animals were used in each of six treatment groups, including negative and positive controls. All groups received a single oral intubation. The negative and positive control groups were treated with vehicle and cyclophosphamide (20 mg/kg body weight), respectively. Male animals were dosed with the test article at 1120 (two groups), 560 (one group) and 280 (one group) mg/kg body weight. Female animals were dosed with the test article at 940 (two groups), 470 (one group) and 235 (one group) mg/kg body weight. Three additional male and female animals were dosed with the highest dose level to correct for possible deaths. The following toxic signs were observed in males dosed with 1120 mg test article/kg body weight: lethargy, hunched posture, ataxia and rough coat. In females dosed with 940 mg test article/kg body weight the following toxic signs were observed: rales, ataxia, lethargy, hunched posture and rough coat. Two males dosed with 1120 mg/kg body weight and three females dosed with 940 mg test article/kg body weight died after dosing. No abnormalities were observed in the animals of the positive and negative control group, in males dosed with 560 and 280 mg test article/kg body weight and in females dosed with 470 and 235 mg test article/kg body weight. Bone marrow of the groups treated with test article was sampled 12-18 or 36-44 (highest dose only) hours after dosing. Bone marrow from the negative and positive control group was harvested 12-18 hours after dosing. The positive control chemical cyclophosphamide induced a statistically significant increase in the number of cells with chromosome aberrations. The test article did not induce a statistically significant increase in the number of cells with chromosome aberrations. No effects of the test article on the number of polyploid cells or cells with endoreduplicated chromosomes were observed. The test article does not disturb mitotic processes and cell cycle progression and does not induce numerical chromosome aberrations under the experimental study conditions.