2,6-difluorobenzamide

Endpoint summary

Key value for chemical safety assessment

Genetic toxicity in vitro

Description of key information

2,6-Difluorobenzamide did not cause gene mutations in an Ames test.

Link to relevant study records

Reference

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other: Non-GLP, near guideline study, available as unpublished reoprt, no restrictions, fully adequate for assessment.

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 472 (Genetic Toxicology: Escherichia coli, Reverse Mutation Assay)

GLP compliance:

no

Type of assay:

bacterial reverse mutation assay

Target gene:

histidine

Species / strain / cell type:

S. typhimurium TA 1535, TA 1537, TA 98, TA 100 and E. coli WP2

Species / strain / cell type:

S. typhimurium TA 1538

Metabolic activation:

with and without

Metabolic activation system:

rat liver S9 (pre-treated with Aroclor 1254)

Test concentrations with justification for top dose:

31.25, 62.5, 125, 500, 1000, 200 and 4000 μg/plate

Vehicle / solvent:

DMSO

Untreated negative controls:

yes

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: benzo(a)pyrene, sodium azide, neutral red and potassium dichromate

Details on test system and experimental conditions:

METHOD OF APPLICATION: in agar (plate incorporation)

DURATION
- Exposure duration: 48-72 h at 37 °C

NUMBER OF REPLICATIONS: three plates per dose/control

Evaluation criteria:

Results are expressed as a ratio: mean number of revertant colonies per treated plate / mean number of revertant colonies per control plate.
Reproducible values of 2.5 x a control value or greater are considered to indicate a mutagenic response.

Species / strain:

S. typhimurium TA 1535, TA 1537, TA 98, TA 100 and E. coli WP2

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:

S. typhimurium TA 1538

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

Additional information on results:

The test compound was totally miscible in the test system at amounts up to 4000 µg per plate.

Remarks on result:

other: all strains/cell types tested

Remarks:

Migrated from field 'Test system'.

Conclusions:

Interpretation of results (migrated information):
negative without metabolic activation
negative with metabolic activation

It was concluded that the test substance did not induce reverse gene mutation in the selected bacterial tester strains under the experimental conditions described.

Executive summary:

The mutagenic activity of the test substance was investigatedin agar layer cultures of selected bacterial tester strains of Salmonella typhimurium and Escherichia coli. Assays were performed both in the presence and in the absence of a S9 microsomal fraction obtained from a liver homogenate from rats pre-treated with Arochlor 1254.

It was concluded that the test substance did not induce reverse gene mutation in the selected bacterial tester strains under the experimental conditions described.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (negative)

Additional information

Additional information from genetic toxicity in vitro:

2,6-Difluorobenzamide was tested in a reverse mutation assay equivalent to OECD guidelines 471 and 472 (Sittingbourne Research Centre, 1987). In this study, Salmonella typhimurium strains TA98, TA100, TA1535 and TA1537 and E. coli strain WP2 were exposed to 31.25 - 4000 µg/plate test substance in DMSO in a plate incorporation test with and without metabolic activation. The test substance did not lead to an increase in the number of revertant colonies either with or without metabolic activation. No cytotoxicity was observed in any of the tester strains at any concentration.

Justification for selection of genetic toxicity endpoint
Most reliable study

Justification for classification or non-classification

Dangerous Substance Directive (67/548/EEC)

The available in vitro study is considered reliable and suitable for classification purposes under 67/548/EEC. As a result the substance is not considered to be classified for mutagenicity under Directive 67/548/EEC, as amended for the 31st time in Directive2009/2/EC.

 

Classification, Labelling, and Packaging Regulation (EC) No 1272/2008

The available experimental test data are reliable and suitable for classification purposes under Regulation 1272/2008. As a result the substance is not considered to be classified for mutagenicity under Regulation (EC) No 1272/2008, as amended for the fifth time in Directive EC 944/2013.