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Administrative data

Endpoint:
in vitro gene mutation study in bacteria
Type of information:
experimental study
Adequacy of study:
key study
Study period:
1989-08-03 - 1989-10-11
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1989
Report date:
1989

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
OECD Guideline 471 (Bacterial Reverse Mutation Assay)
GLP compliance:
yes (incl. QA statement)
Type of assay:
bacterial reverse mutation assay

Test material

Constituent 1
Chemical structure
Reference substance name:
2-chlorobenzonitrile
EC Number:
212-836-5
EC Name:
2-chlorobenzonitrile
Cas Number:
873-32-5
Molecular formula:
C7H4ClN
IUPAC Name:
2-chlorobenzonitrile
impurity 1
Reference substance name:
unknown
IUPAC Name:
unknown
Test material form:
solid

Method

Target gene:
histidine-gene
Species / strainopen allclose all
Species / strain / cell type:
S. typhimurium TA 1535, TA 1537, TA 98 and TA 100
Species / strain / cell type:
S. typhimurium TA 1538
Metabolic activation:
with and without
Metabolic activation system:
rat liver post-mitochondrial fraction (S-9)
Test concentrations with justification for top dose:
initial range-finder: 0, 8, 40, 200, 1000, 5000 µg/plate
main experiment: TA98: 0, 500, 1000, 1500, 2000, 2500 (without S9)
main experiment: all other strains: 0, 1000, 1500, 2000, 2500, 3000 (without S9)
main experiment: all strains: 0, 1000, 2000, 3000, 4000, 5000 (with S9)
Controls
Untreated negative controls:
yes
Negative solvent / vehicle controls:
yes
Remarks:
DMSO
True negative controls:
no
Positive controls:
yes
Positive control substance:
9-aminoacridine
2-nitrofluorene
sodium azide
other: 2-aminoanthracene
Statistics:
F-test

Results and discussion

Test resultsopen allclose all
Key result
Species / strain:
S. typhimurium TA 98
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
cytotoxicity
Remarks:
highest concentration, w/o S9
Vehicle controls validity:
valid
Untreated negative controls validity:
not examined
Positive controls validity:
valid
Key result
Species / strain:
S. typhimurium TA 100
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
no cytotoxicity
Vehicle controls validity:
valid
Untreated negative controls validity:
not examined
Positive controls validity:
valid
Key result
Species / strain:
S. typhimurium TA 1535
Metabolic activation:
with and without
Genotoxicity:
negative
Remarks:
small increas of revertants w/o S9
Cytotoxicity / choice of top concentrations:
no cytotoxicity
Vehicle controls validity:
valid
Untreated negative controls validity:
not examined
Positive controls validity:
valid
Key result
Species / strain:
S. typhimurium TA 1537
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
no cytotoxicity
Vehicle controls validity:
valid
Untreated negative controls validity:
not examined
Positive controls validity:
valid
Key result
Species / strain:
S. typhimurium TA 1538
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
no cytotoxicity
Vehicle controls validity:
valid
Untreated negative controls validity:
not examined
Positive controls validity:
valid
Additional information on results:
RANGE-FINDING/SCREENING STUDIES:
Initial range-finder treatment of strain TA100 was carried out 8, 40, 200, 100 and 5000 µg/plate. The treatment resulted in complete toxicity at 5000 µg/plate in the absence of S9, and a reduction in revertant numbers on plates treated with S9. In the main study concentrations were reduced to 2500 µg/plate (TA 98) and 3000 µg/plate (all other strains) in the absence of S9.

Applicant's summary and conclusion

Conclusions:
2-chlorobenzonitrile did not induce mutation in five strains of Samonella typhimurim, when tested up the cytotoxicity limit, both in the absence and presence of metabolic activation.
Executive summary:

In a reverse gene mutation assay in bacteria, strains TA 1535, TA 1537, TA 1538, TA 98 and TA 100 of S. typhimurium were exposed to 2-chlorobenzonitrile dissolved in dimethyl sulphoxide (DMSO) at concentrations of up to 5000 µg/plate in the presence and absence of mammalian liver post-mitochondrial fraction (S-9) as metabolic activation. There was no evidence of induced mutant colonies over background.

 

This study is classified as acceptable. This study satisfies the requirement for Test Guideline OECD 471 for in vitro mutagenicity (bacterial reverse gene mutation).