Registration Dossier

Administrative data

Endpoint:
in vivo mammalian somatic cell study: cytogenicity / erythrocyte micronucleus
Type of information:
experimental study
Adequacy of study:
key study
Study period:
Oct 1991 - March 1992
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1992
Report date:
1992

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
OECD Guideline 474 (Mammalian Erythrocyte Micronucleus Test)
GLP compliance:
yes
Type of assay:
mammalian bone marrow chromosome aberration test

Test material

Constituent 1
Chemical structure
Reference substance name:
N-Pentanoyl-N-{[2'-(1H-tetrazol-5-yl)biphenyl-4-yl]methyl}-L-valine
EC Number:
604-045-2
Cas Number:
137862-53-4
Molecular formula:
C24 H29 N5 O3
IUPAC Name:
N-Pentanoyl-N-{[2'-(1H-tetrazol-5-yl)biphenyl-4-yl]methyl}-L-valine
Test material form:
solid: particulate/powder

Test animals

Species:
rat
Strain:
other: Tif: RAIf (SPF)
Details on species / strain selection:
Young adult male and female rats under SPF conditions by CIBA-GEIGY. (Tif: RAif (SPF) were reared They were obtained from the animal farm at least one day prior to being used in the test. The air-conditioned animal rooms were maintained at a temperature of 19-23°C and a relative humidity of 40-70%. The room was
illuminated for 12 hours daily. The rats were fed a standard diet of NAFAG No. 890 and tap water ad libitum. Maximal 5 animals were housed per cage, identified by cage card and individual ear tags.
Sex:
male/female

Administration / exposure

Route of administration:
oral: gavage
Vehicle:
Arachis oil
Details on exposure:
58 female ( f) and 58 male (m) rats were treated. The test substance and the negative control were dosed at a volume of 10 ml/kg body weight by gavage. The positive control CPA (20 mg/kg) was administered intraperitoneally.
In the first step of the tolerability test the maximum dose of 3125. o mg/kg of CGP 48 933 as well as the two lower doses of 781.3 mg/kg and 195.3 mg/kg caused no death and no symptoms of toxicity in the treated animals. In the second step of the tolerability test two animals were treated with the dose of
3125.0 mg/kg. None of the animals died and therefore this dose was selected as the highest dose to be administered in the micronucleus test.
Duration of treatment / exposure:
The test was performed with doses of 312 5. o mg/kg b. w, 1562.5 mg/kg b.w. and 781.3 mg/kg b.w. at each of three sampling times of 16, 24 and 48 hours.
Frequency of treatment:
The test was performed with doses of 312 5. o mg/kg b. w, 1562.5 mg/kg b.w. and 781.3 mg/kg b.w. at each of three sampling times of 16, 24 and 48 hours.
Post exposure period:
16, 24 and 48 hours
Doses / concentrationsopen allclose all
Dose / conc.:
3 125 mg/kg bw/day
Dose / conc.:
1 562.5 mg/kg bw/day
Dose / conc.:
781.3 mg/kg bw/day
No. of animals per sex per dose:
58 female (f) and 58 male (m) rats were treated

Treatment High Intermed. Low Positive Negative
dose (HD) dose (ID) dose (LD) control control
(1/2 HD) (1/4 HD) (CPA) (vehicle)
Number/sex 15m + 15f 15m + 15f 15m + 15f 15m + 15f 15m + 15f
Control animals:
yes, concurrent vehicle
Positive control(s):
The positive control was cyclophosphamide - CPA

Examinations

Tissues and cell types examined:
Bone marrow was harvested from the shafts of both femurs in fetal calf serum. Nucleated cells were removed by a cellulose column step.
Details of tissue and slide preparation:
A 10 μm-filter was attached to the nozzle of a 20 ml syringe. Into this syringe 1. 5 g of a mixture ( 1: 1 w/w) of microcrystalline cellulose (Sigmacell type 50) and a-cellulose fibers was placed. Thereafter, the bone marrow suspension was applied to the top of the column and eluted with Hank's BSS buffer. The eluate containing the resuspended in erythrocytes was centrifuged and the cells fetal calf serum. Smears prepared from were this suspension were stained with May-Grunwald/Giemsa solution and mounted.
Evaluation criteria:
The results of the experiments are evaluated with respect to the mean number of PCEs with micronuclei. The groups compared differ by treatment, sampling time and sex of the animals. If there is no significant difference between animals of either sex, the data from females and males are pooled for evaluation.
Statistics:
The significance of differences was assessed by the Chi-SquareTest (Level of significance alfa=0.05, DF=1).

Results and discussion

Test results
Key result
Sex:
male/female
Genotoxicity:
negative
Toxicity:
not specified
Vehicle controls validity:
valid
Negative controls validity:
not applicable
Positive controls validity:
valid

Applicant's summary and conclusion

Conclusions:
It is concluded that under the given experimental conditions no evidence for clastogenic or aneugenic effects was obtained in rats treated with CGP 48 933.