Registration Dossier

Administrative data

Endpoint:
in vivo mammalian somatic cell study: cytogenicity / erythrocyte micronucleus
Type of information:
experimental study
Adequacy of study:
supporting study
Study period:
2000
Reliability:
4 (not assignable)
Rationale for reliability incl. deficiencies:
abstract

Data source

Reference
Reference Type:
secondary source
Title:
Unnamed
Year:
2000
Report Date:
2000

Materials and methods

Test guideline
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 474 (Mammalian Erythrocyte Micronucleus Test)
Deviations:
not specified
GLP compliance:
not specified
Type of assay:
micronucleus assay

Test material

Reference
Name:
Unnamed
Type:
Constituent
Type:
impurity
Type:
impurity
Type:
impurity
Type:
impurity
Type:
impurity
Test material form:
liquid

Test animals

Species:
mouse
Strain:
B6C3F1
Sex:
male/female

Administration / exposure

Route of administration:
oral: gavage
Duration of treatment / exposure:
13 weeks (micronucleus test at the end of a 90 day study)
Frequency of treatment:
daily
Post exposure period:
no data
Doses / concentrations
Dose / conc.:
600 mg/kg bw/day (nominal)
Remarks:
Basis: actual ingested
No. of animals per sex per dose:
9-10 males; 7-10 females

Results and discussion

Test results
Key result
Sex:
male/female
Genotoxicity:
negative
Toxicity:
yes
Remarks:
systemic toxicity at 37.5 mg/kg/d (females) and 75 mg/kg/d (males)
Vehicle controls validity:
not specified
Negative controls validity:
not specified
Positive controls validity:
not specified

Applicant's summary and conclusion

Conclusions:
Interpretation of results: negative
Benzonitrile did not increase the rate of micronuclei in polychromatic erythrocytes in a micronucleus test conducted at the end of a 90 day study in mice.
Executive summary:

At the end of a sub-chronic oral toxicity study in 7-10 B6C3F1-mice/sex/dose a micronucleus test was conducted. Exposure to benzonitrile did not increase the rate of micronuclei in polychromatic erythrocytes at doses up to 600 mg/kg/d. This micronucleus test conducted at the end of a 90 day study is valid according to OECD 474. Systemic adverse effects were reported at 37.5 mg/kg/d. Benzonitrile is considered to be not mutagenic in vivo.