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Toxicological information

Genetic toxicity: in vitro

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Administrative data

Endpoint:
in vitro gene mutation study in bacteria
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Comparable to guideline study with acceptable restrictions

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1985
Report date:
1985

Materials and methods

Test guideline
Qualifier:
equivalent or similar to guideline
Guideline:
OECD Guideline 471 (Bacterial Reverse Mutation Assay)
Version / remarks:
then in force: adopted 23 May 1983
GLP compliance:
no
Type of assay:
bacterial reverse mutation assay

Test material

Constituent 1
Chemical structure
Reference substance name:
2-methylimidazole
EC Number:
211-765-7
EC Name:
2-methylimidazole
Cas Number:
693-98-1
Molecular formula:
C4H6N2
IUPAC Name:
2-methyl-1H-imidazole
Details on test material:
- Name of test material (as cited in study report): 2-methylimidazole
- Test substance no.: 85/26

Method

Target gene:
histidine
Species / strain
Species / strain / cell type:
S. typhimurium TA 1535, TA 1537, TA 98 and TA 100
Metabolic activation:
with and without
Metabolic activation system:
Aroclor induced rat S-9 mix
Test concentrations with justification for top dose:
20-5000 µg/plate (standard plate test)
Vehicle / solvent:
- Vehicle used: water
Controlsopen allclose all
Untreated negative controls:
yes
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
other: 2-aminoanthracene
Remarks:
with S-9
Untreated negative controls:
yes
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
N-ethyl-N-nitro-N-nitrosoguanidine
Remarks:
without S-9 for TA100 and TA1535
Untreated negative controls:
yes
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
other: 4-nitro-o-phenylendiamine
Remarks:
without S-9 for TA98
Untreated negative controls:
yes
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
other: 9-aminoacridine chloride monohydrate
Remarks:
without S-9 for TA1537
Details on test system and experimental conditions:
METHOD OF APPLICATION: in agar (plate incorporation)

NUMBER OF REPLICATIONS: three plates per dose/control

DURATION
- Exposure duration: 48 hours at 37 °C in the dark

DETERMINATION OF CYTOTOXICITY
- Method: relative total growth
Evaluation criteria:
In general, a substance to be characterized as positive in the Ames test has to fulfill the following requirements:
- doubling of the spontaneous mutation rate (control);
- dose-response relationship;
- reproducibility of the results.

Results and discussion

Test resultsopen allclose all
Species / strain:
S. typhimurium TA 1535, TA 1537, TA 98 and TA 100
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
no cytotoxicity
Vehicle controls validity:
valid
Untreated negative controls validity:
valid
Positive controls validity:
valid
Species / strain:
other: E. coli WP2 uvrA or S. typhimurium TA102
Metabolic activation:
with and without
Genotoxicity:
other: no 5th strain tested due to negative in vivo results
Cytotoxicity / choice of top concentrations:
other: Not tested
Additional information on results:
Toxicity: A bacteriotoxic effect (reduced his- background growth) was not observed.
Solubility: Complete solubility of the test substance in aqua dest.

There are in vivo studies available with negative results, thus, testing with a further strain, e.g. E. coli or S. typhimurium TA102 would not change the overall outcome.

Applicant's summary and conclusion