trans-2-(4-Bromo-3-fluorophenyl)-5-butyl-[1,3]dioxane

Endpoint summary

Key value for chemical safety assessment

Genetic toxicity in vitro

Description of key information

For the assessment of mutagenicity, in vitro methods have been applied. The following results have been obtained:

OECD 471: negative

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

Study period:

Nov 27, 2018 - Mar 05, 2019

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Version / remarks:

adopted 21 July 1997

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method B.13/14 (Mutagenicity - Reverse Mutation Test Using Bacteria)

Version / remarks:

8 June 2000

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Type of assay:

bacterial reverse mutation assay

Target gene:

HIS operon (S. thyphimurium)
TRP operon (E. coli)

Species / strain / cell type:

S. typhimurium TA 98

Details on mammalian cell type (if applicable):

his D 3052, uvrB, rfa + R-factor (pKM101)

Additional strain / cell type characteristics:

other: mutations in the histidine operon

Species / strain / cell type:

S. typhimurium TA 100

Details on mammalian cell type (if applicable):

his G 46, uvrB, rfa + R-factor (pKM101)

Additional strain / cell type characteristics:

other: mutations in the histidine operon

Species / strain / cell type:

S. typhimurium TA 1535

Details on mammalian cell type (if applicable):

his G 46, uvrB, rfa

Additional strain / cell type characteristics:

other: mutations in the histidine operon

Species / strain / cell type:

S. typhimurium TA 1537

Details on mammalian cell type (if applicable):

his C 3076, uvrB, rfa

Additional strain / cell type characteristics:

other: mutations in the histidine operon

Species / strain / cell type:

E. coli WP2

Details on mammalian cell type (if applicable):

trp-, uvrA

Additional strain / cell type characteristics:

other: mutations in the tryptophan operon

Metabolic activation:

with and without

Metabolic activation system:

liver S9 mix from beta-Naphthoflavone/Phenobarbital-pretreated rats with standard co-factors

Test concentrations with justification for top dose:

The test material concentrations used were selected according to the EEC, OECD and Japanese guidelines for this test system. DMSO was selected as solvent for the current experiment and 5000 µg/plate was chosen as the appropriate maximum test material concentration.

Vehicle / solvent:

DMSO

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

4-nitroquinoline-N-oxide

9-aminoacridine

sodium azide

other: Daunomycin

Remarks:

without S9

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: 2-aminoanthracene

Remarks:

with S9

Details on test system and experimental conditions:

Bacterial strains were tested in accordance with the plate incorporation method. 3 parallel plates were used for each concentration step of the test material. The incubation of plates was performed at 36-38°C for 2 days. Liver S9 mix from rats pre-treated with beta-Naphthoflavone/Phenobarbital was used as the metabolic activation system. Two experimental series were performed, containing 10% S9 ind the 1st and 20% S9 in the 2nd series.

Rationale for test conditions:

according to Guideline

Evaluation criteria:

A test material was to be defined as positive or mutagenic in this assay if
• the assay is considered valid and
• a biologically relevant increase in the mean number of revertants above a threshold of 2-fold (TA 98, TA 100, WP2 uvrA) or 3-fold (TA 1535, TA 1537) as compared to the con-current negative controls is observed
• an increase exceeding the threshold at only one concentration is considered as biologically meaningful if reproduced in a second independent experiment
• a concentration-dependent increase is considered biologically meaningful if the threshold is exceeded at more than one concentration

A test material is defined as negative or non-mutagenic in this assay if
• the assay is considered valid and
• none of the above-mentioned criteria are met

Whenever colony counts remain within the historical range of negative controls, such increases are considered as biologically not meaningful. In general, two series of experiments must be performed. However, there is no requirement for verification of a clear positive response according to OECD TG 471 (1997).

Results which only partially satisfied the above criteria were dealt with on a case by case basis. Biological relevance was considered, for example consistency of response within and between concentrations and (where applicable) between experiments.

Statistics:

According to the OECD guideline 471, a statistical analysis of the data is not mandatory.

Key result

Species / strain:

S. typhimurium TA 98

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity, but tested up to precipitating concentrations

Vehicle controls validity:

valid

Untreated negative controls validity:

not examined

True negative controls validity:

not examined

Positive controls validity:

valid

Key result

Species / strain:

S. typhimurium TA 100

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity, but tested up to precipitating concentrations

Vehicle controls validity:

valid

Untreated negative controls validity:

not examined

True negative controls validity:

not examined

Positive controls validity:

valid

Key result

Species / strain:

S. typhimurium TA 1535

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity, but tested up to precipitating concentrations

Vehicle controls validity:

valid

Untreated negative controls validity:

not examined

True negative controls validity:

not examined

Positive controls validity:

valid

Key result

Species / strain:

S. typhimurium TA 1537

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity, but tested up to precipitating concentrations

Vehicle controls validity:

valid

Untreated negative controls validity:

not examined

True negative controls validity:

not examined

Positive controls validity:

valid

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

Vehicle controls validity:

valid

Untreated negative controls validity:

not examined

True negative controls validity:

not examined

Positive controls validity:

valid

Conclusions:

With and without addition of S9 mix as the external metabolizing system, the test item was not mutagenic under the experimental conditions described.

Executive summary:

Objective

The present study was conducted to investigate the test material for mutagenic potential in a bacterial reverse gene mutation assay in the absence and presence of a rat liver metabolizing system (S9 mix).

Study Design

The investigations for the mutagenic potential of the test item were performed using Salmonella typhimurium tester strains TA 98, TA 100, TA 1535 and TA 1537, and Escherichia coil WP2 uvrA. The plate incorporation test with and without addition of liver S9 mix from rats pre-treated with beta-Naphthoflavone/Phenobarbital was used. In this study, two independent experimental series were performed. The S9 mix used contained 10% S9 in the 1st and 20% S9 in the 2nd series.

Results

The mean numbers of revertants of the current negative controls were within the range of historical negative control values. The strain specific positive control test materials, namely daunomycin, sodium azide, 4-nitroquinolin-N-oxide, and 9-aminoacridine in the absence of S9 mix, yielded the expected mutant frequencies that were greatly in excess of the negative controls. The genotype of the tester strains used was thus confirmed. 2-Aminoanthracene which require metabolic activation, was strongly mutagenic. This indicates that the exogenous metabolizing system used in the present investigation (S9 mix) was active. Thus, the study is considered valid.

Under the conditions described, there were no relevant increases in revertant numbers observed after exposure to the test item in the absence and presence of S9 mix.

Conclusion

It was concluded that with and without addition of S9 mix as the exogenous metabolizing system, the test item was not mutagenic under the experimental conditions described.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (negative)

Genetic toxicity in vivo

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information

There were no relevant increases in revertant numbers observed after exposure to the test item in the absence and presence of S9 mix under the conditions of the study according to OECD Guideline 471.

Justification for classification or non-classification

Based on the provided the test item is not classified for mutagenicity according to Regulation (EC) No 1272/2008.