Ethyl difluoroacetate

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: GLP, Guideline study (OECD)

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2007

Report date:

2007

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

Test material information

Constituent 1

Reference substance name:

Ethyl difluoroacetate

EC Number:

207-223-4

EC Name:

Ethyl difluoroacetate

Cas Number:

454-31-9

Molecular formula:

C4H6F2O2

IUPAC Name:

ethyl difluoroacetate

Details on test material:

- Name of test material (as cited in study report): Ethyl difluoroacetate
- Physical state: Liquid, colorless, clear
- Analytical purity: 99.9%
- Lot/batch No.: 33244/106 A
- Storage condition of test material: Refrigerator. The stability of the test substance under storage conditions throughout the study period was guaranteed as indicated by the sponsor and the sponsor holds this responsibility.
- Other: The homogeneity of the test substance was ensured by mixing before preparation of the test substance solutions.
- Date of production: 19 Apr 2007

Method

Target gene:

his, trp

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:

0; 20; 100; 500; 2 500 and 5 000 μg/plate

Vehicle / solvent:

- Vehicle(s)/solvent(s) used: DMSO
- Justification for choice of solvent/vehicle: Due to the limited solubility of the test substance in water, DMSO was used as vehicle, which had been demonstrated to be suitable in bacterial reverse mutation tests and for which historical control data are available.

Controls

Controls 1

Untreated negative controls:

yes

Negative solvent / vehicle controls:

yes

Positive controls:

yes

Positive control substance:

other: 2-aminoanthracene

Remarks:

with S9 mix

Controls 2

Untreated negative controls:

yes

Negative solvent / vehicle controls:

yes

Positive controls:

yes

Positive control substance:

other: N-methyl-N'-nitro-N-nitrosoguanidine, 4-nitro-o-phenylendiamine (NOPD), 9-aminoacridine (AAC), 4-nitroquinoline-N-oxide (4-NQO)

Remarks:

without S9 mix

Details on test system and experimental conditions:

METHOD OF APPLICATION: standard plate test and preincubation test

DURATION
- Preincubation period: 20 min
- Exposure duration: 48-72h

Individual plate counts, the mean number of revertant colonies per plate and the standard
deviations were given for all dose groups as well as for the positive and negative (vehicle) controls in all experiments.

DETERMINATION OF CYTOTOXICITY
• decrease in the number of revertants
• clearing or diminution of the background lawn (= reduced his- or trp- background growth)
• reduction in the titer

OTHER EXAMINATIONS:
- The titer is generally determined only in the experimental parts with S9 mix both for the negative controls (vehicle only) and for the two highest doses in all experiments.

Evaluation criteria:

The test chemical is considered positive in this assay if the following criteria are met:
• A dose-related and reproducible increase in the number of revertant colonies, i.e. about doubling of the spontaneous mutation rate in at least one tester strain either without S9 mix or after adding a metabolizing system.

A test substance is generally considered non-mutagenic in this test if:
• The number of revertants for all tester strains were within the historical negative control range under all experimental conditions in at least two experiments carried out independently of each other.

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:

5 000 μg/plate in TA1537

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:

> 1 250 μg/plate

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Additional information on results:

No test substance precipitation was found with and without S9 mix.

Applicant's summary and conclusion

Conclusions:

Interpretation of results (migrated information):
negative

Under the experimental conditions of the study, it is concluded that Ethyl difluoroacetate is not a mutagenic substance in the bacterial reverse mutation test in the absence and the presence of metabolic activation.