5-[(2,3-dihydro-6-methyl-2-oxo-1H-benzimidazol-5-yl)azo]barbituric acid

Genetic toxicity: in vivo

Administrative data

Endpoint:

in vivo mammalian somatic cell study: cytogenicity / erythrocyte micronucleus

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1981

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1981

Report date:

1981

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 474 (Mammalian Erythrocyte Micronucleus Test)

Principles of method if other than guideline:

BOLLER, K. and W. SCHMID (1970), Chemische Mutagenese beim Säuger.
Das Knochenmark des Chinesischen Hamsters als in vivo-Testsystem.
Hamatologische Befunde nach Behandlung mit Trenimon.
Humangenetik 11, 35-54.

MATTER, B. and W. SCHMID (1971), Trenimon-Induced Chromosomal
Damage in Bone Marrow Cells of Six Mammalian Species, Evaluated
by the Micronucleus Test.
Mutation Res. 12, 417-425.

MULLER, D., M. LANGAUER, R. RATHENBERG, F.F. STRASSER and
R. HESS (1972), Mikrokerntest sowie Chromosomenuntersuchungen
an somatischen und gonosomalen Zellen des Chinesischen Hamsters
nach Cyclophosphamidgabe.
Verh. Dtsch. Ges. Path. 56, 381-384.

GLP compliance:

no

Remarks:

prior to GLP implementation

Type of assay:

micronucleus assay

Test material

Test material information

Constituent 1

Reference substance name:

5-[(2,3-dihydro-6-methyl-2-oxo-1H-benzimidazol-5-yl)azo]barbituric acid

EC Number:

276-344-2

EC Name:

5-[(2,3-dihydro-6-methyl-2-oxo-1H-benzimidazol-5-yl)azo]barbituric acid

Cas Number:

72102-84-2

Molecular formula:

C12H10N6O4

IUPAC Name:

5-[(1E)-2-(6-methyl-2-oxo-2,3-dihydro-1H-1,3-benzodiazol-5-yl)diazen-1-yl]-1,3-diazinane-2,4,6-trione

Test material form:

solid

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- lot/batch No.of test material: EN 63699

Test animals

Species:

hamster

Strain:

not specified

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS

- Weight at study initiation: female 21-27 g, male 23-28 g
- Fasting period before study: no data
- Housing: no data
- Diet: ad libitum
- Water: ad libitum

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 23-24
- Humidity (%): 62-68
- Photoperiod (hrs dark / hrs light): 12/12

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

CMC0.5%

Details on exposure:

PREPARATION OF DOSING SOLUTIONS:

DIET PREPARATION
- Rate of preparation of diet (frequency): daily
- Mixing appropriate amounts with (Type of food): CMC

Duration of treatment / exposure:

2d

Frequency of treatment:

daily

Post exposure period:

24h

Doses / concentrations

Doses / concentrations 1

Dose / conc.:

750 mg/kg bw/day (actual dose received)

Doses / concentrations 2

Dose / conc.:

1 500 mg/kg bw/day (actual dose received)

Doses / concentrations 3

Dose / conc.:

3 000 mg/kg bw/day (actual dose received)

No. of animals per sex per dose:

6

Control animals:

yes, concurrent vehicle

Positive control(s):

Cyclophosphamide (ENDOXAN ): 128 mg/kg in 20 ml/kg in 0.5% CMC

Examinations

Tissues and cell types examined:

Bone marrow was harvested from the shafts of both femurs

Details of tissue and slide preparation:

CRITERIA FOR DOSE SELECTION: acute oral toxicity study

TREATMENT AND SAMPLING TIMES ( in addition to information in specific fields): The preparation was administered orally to groups of 6 female and 6 male animals each. Treatment consisted of daily one application on 2 consecutive days. 24 h after the second application the animals were sacrificed by dislocation of the cervical vertebrae.

DETAILS OF SLIDE PREPARATION: In a siliconized pipette filled with approx. 0.5 µL rat serum the bone marrow was drawn up. In order to receive a homogeneous suspension the content of pipette was aspirated gently about three times. Small drops of the mixture were transferred on the end of a slide, spread out by pulling it behind a polished cover glass and the preparations were air-dried. Three hours later, the slides were stained in undiluted May-Griinwald solution for 2 min then in May-Griinwald solution/water 1/1 for 2 min and then in Giemsa's, 40% for 20 min. After being rinsed in methanol 55% for 5-8 sec and washed off twice in water, they were left immersed in water for approx. 2 min. After rinsing with distilled 'water and air-drying, the slides were cleared in Xylol and mounted in Eukitt.

METHOD OF ANALYSIS: The slides of three female and three male animals each of the negative control group, the positive control group and of the
groups treated with various doses of the test item were examined. 1000 bone marrow cells each were scored per animal and the following
anomalies were registered:
a) Single Jolly bodies,
b) fragments of nuclei in erythrocytes,
c) micronuclei in erythroblasts,
d) micronuclei in leucopoietic cells, e) polyploid cells.

Statistics:

The significance of difference was assessed by chi-sqare~test.

Results and discussion

Test results

Key result

Sex:

male/female

Genotoxicity:

negative

Toxicity:

not specified

Vehicle controls validity:

valid

Negative controls validity:

valid

Positive controls validity:

valid