Acetamide, N-(3',4'-dichloro-5-fluoro[1,1'-biphenyl]-2-yl)-

Genetic toxicity: in vitro

Administrative data

Endpoint:

in vitro gene mutation study in bacteria

Type of information:

experimental study

Adequacy of study:

key study

Study period:

22 May - 24 Oct 2013

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2014

Report date:

2014

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Version / remarks:

adopted in 1997

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Remarks:

Gyemszi, National Institute for Quality- and Organizational Development in Healthcare and Medicines, Budapest, Hungary

Type of assay:

bacterial reverse mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

N-{3',4'-dichloro-5-fluoro-[1,1'-biphenyl]-2-yl}acetamide

EC Number:

620-313-1

Cas Number:

877179-03-8

Molecular formula:

C14H10Cl2FNO

IUPAC Name:

N-{3',4'-dichloro-5-fluoro-[1,1'-biphenyl]-2-yl}acetamide

Method

Target gene:

his operon (for S. typhimurium strains)
trp operon (for E. coli strain)

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:

cofactor supplemented post-mitochondrial fraction (S9 mix), prepared from the livers of rats treated with phenobarbital and beta-naphthoflavone

Test concentrations with justification for top dose:

Preliminary Range Finding Test (S. typhimurium TA 98 and TA 100 only): 10, 31.6, 100, 316, 2500 and 5000 µg/plate with and without metabolic activation
Initial Mutation Test (all S.typhimurium strains and E.coli strain; plate incorporation method) and Confirmatory Mutation Test (all S.typhimurium strains and E.coli strain; pre-incubation method): 5, 15.81, 158.1, 500, 1581, 5000 µg/plate with and without metabolic activation
Complementary Confirmatory Mutation Test (S. typhimurium strains only; pre-incubation method): 0.1581, 0.5, 1.581, 5, 15.81, 50, 158.1, 500 µg/plate without metabolic activation and 0.5, 1.581, 5, 15.81, 50, 158.1, 500, 1581 µg/plate with metabolic activation

The top dose of the preliminary range finding test, the initial mutation test and the confirmatory mutation test is the recommended maximum test concentration for soluble non-cytotoxic substances according to the OECD guideline 471. The top dose of the complementary confirmatory mutation test in S. typhimurium strains was chosen based on cytotoxic effects observed in the previous tests.

Vehicle / solvent:

- Vehicle/solvent used: DMSO
- Justification for choice of solvent/vehicle: The solubility of the test item was examined using distilled water, dimethyl sulfoxide (DMSO) and N,N-dimethylformamide (DMF). No proper formulation was achieved using distilled water as vehicle at 100 mg/mL concentration. However the formulations using DMSO or DMF as vehicle at the same concentration were suitable for the test. Due to the better biocompatibility, DMSO was selected as vehicle for the study.

Controls

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

Remarks:

DMSO and distilled water

True negative controls:

no

Positive controls:

yes

Positive control substance:

9-aminoacridine

sodium azide

methylmethanesulfonate

other: 4-nitro-1,2-phenylene-diamine (NPD): - S9, 4 µg/plate in DMSO for S. typhimurium TA 98 2-aminoanthracene (2AA): +S9, 2 µg/plate in DMSO for S. typhimurium TA 98, TA 100, TA 1535, TA 1537; +S9, 50 µg/plate in DMSO for E.coli WP2 uvrA

Remarks:

The S9 batch was characterised with benzo(a)pyrene in addition to 2-aminoanthracene as mutagen that requires metabolic activation.

Results and discussion

Test results

Test results 1

Key result

Species / strain:

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

Metabolic activation:

with

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Remarks:

at 500 µg/plate and above

Vehicle controls validity:

valid

Untreated negative controls validity:

not examined

Positive controls validity:

valid

Test results 2

Key result

Species / strain:

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

Metabolic activation:

without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Remarks:

at 158.1 µg/plate and above

Vehicle controls validity:

valid

Untreated negative controls validity:

not examined

Positive controls validity:

valid

Test results 3

Key result

Species / strain:

E. coli WP2 uvr A

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity, but tested up to precipitating concentrations

Remarks:

(5000 µg/plate)

Vehicle controls validity:

valid

Untreated negative controls validity:

not examined

Positive controls validity:

valid

Applicant's summary and conclusion

Conclusions:

In this mutagenicity test in bacteria, the test substance was not mutagenic in any of the four Salmonella typhimurium strains (TA 1535, TA 1537, TA 98, TA 100) or in Escherichia coli WP2 uvrA tested with and without metabolic activation up to 5000 µg/plate in the plate incorporation test as well as in the pre-incubation test. Using the pre-incubation method a bacteriotoxic effect was noted at 158.1 μg/plate and above in all Salmonella typhimurium without metabolic activation and at 500 µg/plate and above with metabolic activation. Using the plate incorporation method a bacteriotoxic effect was noted at 1581 μg/plate and above in Salmonella typhimurium TA 100 without metabolic activation and at 5000 µg/plate with metabolic activation. In Salmonella typhimurium TA 1535 a bacteriotoxic effect was observed at 5000 µg/plate with and without metabolic activation. No bacteriotoxic effect was noted for the Escherichia coli WP2 uvrA strain; however, precipitation of the test substance was observed at 5000 µg/plate.