α-(2,4-dichlorophenyl)-1H-imidazole-1-ethanol

Genetic toxicity: in vitro

Administrative data

Endpoint:

in vitro gene mutation study in bacteria

Remarks:

Type of genotoxicity: gene mutation

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Well documented study according to internationally accepted guidelines and GLP compliant

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2013

Report date:

2013

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Type of assay:

bacterial reverse mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

α-(2,4-dichlorophenyl)-1H-imidazole-1-ethanol

EC Number:

246-042-5

EC Name:

α-(2,4-dichlorophenyl)-1H-imidazole-1-ethanol

Cas Number:

24155-42-8

Molecular formula:

C11H10Cl2N2O

IUPAC Name:

1-(2,4-dichlorophenyl)-2-(1H-imidazol-1-yl)ethan-1-ol

Test material form:

solid: crystalline

Details on test material:

Test item: IMIDAZOLE ETHANOL (CAS No. 24155-42-8)
Batch No.: L36066N
Physical state: Light-yellow powder
Active ingredient content (titrimetry): 92.1%
Impurities (HPLC): 9.18%
Storage: 15-30°C

Method

Target gene:

S. typhimurium TA98: hisD3052; TA100: hisG46; TA1535: hisG46; TA1537: hisC3076
E. coli WP2 uvr A: trpE

Species / strain

Species / strain 1

Species / strain / cell type:

S. typhimurium TA 1535, TA 1537, TA 98 and TA 100

Species / strain 2

Species / strain / cell type:

E. coli WP2 uvr A

Metabolic activation:

with and without

Metabolic activation system:

S9 mix

Test concentrations with justification for top dose:

The following concentrations of the test item were prepared and used in the Initial and Confirmatory Mutation Tests:
In Salmonella typhimurium strains:
-without metabolic activation: -S9 Mix: 500, 158, 50, 15.8, 5 and 1.6 μg/plate;
-with metabolic activation: +S9 Mix: 1581, 500, 158, 50, 15.8 and 5 μg/plate;
In Escherichia coli WP2 uvrA:
-with and without metabolic activation: ±S9 Mix: 5000, 1581, 500, 158, 50 and 15.8 μg/plate

Vehicle / solvent:

Dimethyl sulfoxide DMSO
Ultrapure water (UPW)

Controls

Controls 1

Untreated negative controls:

yes

Negative solvent / vehicle controls:

yes

Remarks:

DMSO and UPW

Controls 2

Positive controls:

yes

Remarks:

Without metabolic activation.

Positive control substance:

other: 4-nitro-1,2-phenylene-diamine

Remarks:

Dose: 4 μg/plate; Vehicle: DMSO; Strain: Salmonella TA98

Controls 3

Positive controls:

yes

Remarks:

Without metabolic activation.

Positive control substance:

sodium azide

Remarks:

Dose: 2 μg/plate; Vehicle: UPW; Strain: Salmonella TA100 and TA1535

Controls 4

Positive controls:

yes

Remarks:

Without metabolic activation.

Positive control substance:

9-aminoacridine

Remarks:

Dose: 50 μg/plate; Vehicle: DMSO; Strain: Salmonella TA1537

Controls 5

Positive controls:

yes

Remarks:

Without metabolic activation.

Positive control substance:

methylmethanesulfonate

Remarks:

Dose: 2 μL/plate; Vehicle: UPW; Strain: E.coli WP2uvrA

Controls 6

Positive controls:

yes

Remarks:

With metabolic activation.

Positive control substance:

other: 2-aminoanthracene

Remarks:

Dose: 2μg/plate; Vehicle: DMSO; Strain: all of Salmonella strains

Controls 7

Positive controls:

yes

Remarks:

With metabolic activation.

Positive control substance:

other: 2-aminoanthracene

Remarks:

Dose: 50μg/plate; Vehicle: DMSO; Strain: E.coli strain

Details on test system and experimental conditions:

The study included a Preliminary Solubility Test, a Preliminary Range Finding Test (Informatory Toxicity Test) an Initial Mutation Test (Plate Incorporation Test), and a Confirmatory Mutation Test (Pre-Incubation Test).
In the preliminary Range Finding Test as well as in the Initial Mutation Test the plate incorporation method was used.

Evaluation criteria:

The colony numbers on the control, positive control and the test plates were determined (counted manually), the mean values and appropriate standard deviations and mutation rates were calculated.
An increase is considered biologically relevant if:
- in strain Salmonella typhimurium TA100 the number of reversions is at least twice as high as the reversion rate of the vehicle control;
- in strain TA98, TA1535, TA1537 and Escherichia coli WP2 uvrA the number of reversions is at least three times higher than the reversion rate of the vehicle control
A test item is considered mutagenic if:
- a dose–related increase in the number of revertants occurs and/or;
- a reproducible biologically relevant positive response for at least one of the dose groups occurs in at least one strain with or without metabolic activation

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:

cytotoxicity

Remarks:

All of Salmonella strains: 500 μg/plate (-S9mix)

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Test results 2

Species / strain:

E. coli WP2 uvr A

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Remarks:

1581 μg/plate (+/-S9mix)

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Additional information on results:

The highest revertant colony number increase over the spontaneous rate of the vehicle control plates was observed in Salmonella typhimurium TA1535 at 50 μg/plate in the Initial Mutation Test (Plate Incorporation Test), without metabolic activation (-S9 Mix). The mutation rate was: 2.00. This value was unique and remained below the genotoxicological threshold for being positive.

Remarks on result:

other: all strains/cell types tested

Remarks:

Migrated from field 'Test system'.

Applicant's summary and conclusion

Conclusions:

Interpretation of results (migrated information):
negative

The test item does not induce gene mutations by base pair changes or frameshifts in the genome of the strains used.
In conclusion, the test item “IMIDAZOLE ETHANOL” (CAS NO. 24155-42-8) has no mutagenic activity on the applied bacterium tester strains under the test conditions used in this study.