2-methylimidazole

Genetic toxicity: in vitro

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

Test material information

Constituent 1

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

Controls

Controls 1

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

Controls 2

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

Controls 3

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

Controls 4

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 results

Test results 1

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

Test results 2

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.