4-(2-chlorophenyl)-N-cyclohexyl-N-ethyl-5-oxo-4,5-dihydro-1H-tetrazole-1-carboxamide

Genetic toxicity: in vivo

Administrative data

Endpoint:

in vivo mammalian somatic cell study: cytogenicity / erythrocyte micronucleus

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

28 Feb - 26 Apr 1995

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study with acceptable restrictions

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1995

Report date:

1995

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 474 (Mammalian Erythrocyte Micronucleus Test)

Version / remarks:

29 Jul 2016

Deviations:

yes

Remarks:

yes, sampling of the negative control only once at the latest sampling time point, only one dose < 2000 mg/kg bw tested, plasma levels of test substance not determined, only 1000 polychromatic erythrocytes counted instead of 4000

GLP compliance:

yes

Type of assay:

mammalian erythrocyte micronucleus test

Test material

Test material information

1

Reference substance name:

4-(2-chlorophenyl)-N-cyclohexyl-N-ethyl-5-oxo-4,5-dihydro-1H-1,2,3,4-tetrazole-1-carboxamide

EC Number:

605-140-1

Cas Number:

158237-07-1

Molecular formula:

C16H20ClN5O2

IUPAC Name:

4-(2-chlorophenyl)-N-cyclohexyl-N-ethyl-5-oxo-4,5-dihydro-1H-1,2,3,4-tetrazole-1-carboxamide

Test animals

Species:

mouse

Strain:

other: Hsd/Win: NMRI

Sex:

male/female

Administration / exposure

Route of administration:

intraperitoneal

Duration of treatment / exposure:

not applicable

Frequency of treatment:

single administration

Post exposure period:

16, 24 and 48 h

Doses / concentrations

Dose / conc.:

1 500 mg/kg bw/day (nominal)

No. of animals per sex per dose:

5

Control animals:

yes, concurrent vehicle

Positive control(s):

cyclophosphamide dissolved in deionized water
- Route of administration: intraperitoneal
- Doses / concentrations: 20 mg/kg bw

Examinations

Tissues and cell types examined:

Tissue: bone marrow
Cell type: bone marrow cells

Evaluation criteria:

- A test was considered positive if, at any of the intervals, there was a relevant and significant increase in the number of polychromatic erythrocytes showing micronuclei in comparison to the negative control.
- A test was considered negative if there was no relevant or significant increase in the rate of micronucleated polychromatic erythrocytes at any time.
- A test was also considered negative if there was a significant increase in that rate which, according to the laboratory's experience was within the range of negative controls.
- A test was considered equivocal if there was an increase of micronucleated polychromatic erythrocytes above the range of attached historical negative controls, provided the increase was not significant and the result of the negative control was not closely related to the data of the respective treatment group. In this case, a second test had to be performed at the most sensitive interval.

Statistics:

- Number of polychromatic erythrocytes having micronuclei and the number of normochromatic erythrocytes were checked by Wilcoxon's non-parametric rank sum test.
- The rate of normochromatic erythrocytes containing micronuclei was examined if the micronuclear rate for polychromatic erythrocytes was already relevantly increased. In this case, the group with the highest mean was compared with the negative control using the one-sided chiz-test.

Results and discussion

Test results

Key result

Sex:

male/female

Genotoxicity:

negative

Toxicity:

yes

Remarks:

indicated by apathy, roughened fur, staggering gait, difficulty in breathing, eyelids stuck together, slitted eyes and diarrhoea.

Vehicle controls validity:

valid

Negative controls validity:

not applicable

Positive controls validity:

valid

Any other information on results incl. tables

PCE/NCE ratio:

The ratio of polychromatic (PCE) to normochromatic erythrocytes (NCE) was altered by the treatment, being 1000: 798 (1s=493) in the negative control, 1000: 1130 (1s=302) in the 16 h group, 1000: 1982

(1s=2099) in the 24 h group and 1000: 2483 (ls=528) in the 48 h group.

Micronuclei formation:

No biologically important or statistically significant variations existed between the negative control and the groups treated intraperitoneally with the test substance, with respect to the incidence of micronucleated polychromatic erythrocytes. The incidence of these micronucleated cells was 1.8/1000 (1s=1.2) in the negative control, and 2.2/1000 (1s=1.9), 1.6/1000 (1s=1.0) and 1.8/1000 (1s=1.8)  in the treated groups. The positive control caused a clear in crease in the number of polychromatic erythrocytes with micronuclei indictaed by an incidence of micronucleated cells of 12.2/1000 (1s=3.6), which represents a biologically relevant increase in comparison to the negative control.