3,5-bis(difluoromethyl)-1H-pyrazole

Genetic toxicity: in vitro

Administrative data

Endpoint:

in vitro gene mutation study in bacteria

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

15 - 28 Sep 2017

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2017

Report date:

2017

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Version / remarks:

adopted in 1997

Deviations:

no

Test guideline 2

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Version / remarks:

adopted in 2020

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Remarks:

Behörde für Gesundheit und Verbraucherschutz, Hamburg, Germany

Type of assay:

bacterial reverse mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

3,5-bis(difluoromethyl)-1H-pyrazole

EC Number:

814-072-3

Cas Number:

77614-79-0

Molecular formula:

C5H4F4N2

IUPAC Name:

3,5-bis(difluoromethyl)-1H-pyrazole

Method

Target gene:

His-operon

Species / strain

Species / strain / cell type:

S. typhimurium TA 1535, TA 1537, TA 98, TA 100 and TA 102

Metabolic activation:

with and without

Metabolic activation system:

Cofactor supplemented post-mitochondrial fraction (S9 mix), prepared from the livers of rats treated with Aroclor 1254.

Test concentrations with justification for top dose:

First experiment: 31.6, 100, 316, 1000, 3160 and 5000 µg/plate with and without metabolic activation
Second experiment: 31.6, 100, 316, 1000, 3160 and 5000 µg/plate with and without metabolic activation

The top dose was chosen based on two preliminary cytotoxicity test in TA 100 with and without metabolic activation for which no cytotoxicity was observed up to and including the highest concentration of 5000 µg/plate.

Vehicle / solvent:

- Vehicle/solvent used: DMSO

Controls

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

Remarks:

DMSO

True negative controls:

no

Positive controls:

yes

Positive control substance:

9-aminoacridine

2-nitrofluorene

sodium azide

benzo(a)pyrene

mitomycin C

other: 2-aminoanthracene 2 µg/plate in DMSO (+S9) for TA 100 and TA 1535

Results and discussion

Test results

Test results 1

Key result

Species / strain:

S. typhimurium TA 100

Metabolic activation:

with and without

Genotoxicity:

positive

Remarks:

In the first experiment at 3160 and 5000 µg/plate with and without S9 mix; in the second experiment at 5000 µg/plate without S9 mix and at 3160 and 5000 µg/plate with S9 mix

Cytotoxicity / choice of top concentrations:

no cytotoxicity nor precipitates, but tested up to recommended limit concentrations

Vehicle controls validity:

valid

Untreated negative controls validity:

not examined

True negative controls validity:

not examined

Positive controls validity:

valid

Test results 2

Key result

Species / strain:

S. typhimurium TA 1535

Metabolic activation:

with and without

Genotoxicity:

positive

Remarks:

In the second experiment at 5000 µg/plate without S9 mix and at 1000, 3160 and 5000 µg/plate with S9 mix.

Cytotoxicity / choice of top concentrations:

no cytotoxicity nor precipitates, but tested up to recommended limit concentrations

Vehicle controls validity:

valid

Untreated negative controls validity:

not examined

True negative controls validity:

not examined

Positive controls validity:

valid

Test results 3

Key result

Species / strain:

S. typhimurium, other: TA98, TA102 and TA1537

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity nor precipitates, but tested up to recommended limit concentrations

Vehicle controls validity:

valid

Untreated negative controls validity:

not examined

True negative controls validity:

not examined

Positive controls validity:

valid

Applicant's summary and conclusion

Conclusions:

Under the conditions of the test, the test item was mutagenic in S. typhimurium strains TA100 and TA1535 with and without metabolic activation. There was no mutagenic response in strains TA 98, TA102 and TA1537 with and without metabolic activation up to 5000 µg/plate.