4'-bromo-3-chloropropiophenone

Endpoint summary

Key value for chemical safety assessment

Genetic toxicity in vitro

Description of key information

GLP compliant OECD 471 study: negative with and without metabolic activation

Link to relevant study records

Reference

Endpoint:

in vitro gene mutation study in bacteria

Type of information:

experimental study

Adequacy of study:

key study

Study period:

Jan 29 - Apr 02, 2020

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:

1997

Deviations:

no

Qualifier:

according to guideline

Guideline:

other: Japanese Guidelines for this test system

Version / remarks:

1993

GLP compliance:

yes

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

Additional strain / cell type characteristics:

other: mutations in the histidine operon

Species / strain / cell type:

S. typhimurium TA 100

Additional strain / cell type characteristics:

other: mutations in the histidine operon

Species / strain / cell type:

S. typhimurium TA 1535

Additional strain / cell type characteristics:

other: mutations in the histidine operon

Species / strain / cell type:

S. typhimurium TA 1537

Additional strain / cell type characteristics:

other: mutations in the histidine operon

Species / strain / cell type:

E. coli WP2

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. In a first experiment, the test material was highly cytotoxic, therefore the experiment was repeated with lower test material concentrations, i.e. 158 µg/plate (-S9) and 281 µg/plate (+S9). DMSO was used to prepare the stock solution and the subsequent dilutions under subdued lighting conditions, immediately prior to assay.

1. Series: 0.158, 0.50, 1.58, 5.00, 15.8, 50.0, and 158 µg/plate
2. Series: 1.58, 5.00, 15.8, 50.0, and 88.9 µg/plate

Vehicle / solvent:

Acetone

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

4-nitroquinoline-N-oxide

sodium azide

other: 4-Nitro-o-phenylenediamine

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 concurrent 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.

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:

cytotoxicity

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:

cytotoxicity

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:

cytotoxicity

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:

cytotoxicity

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:

cytotoxicity

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 material were performed usingSalmonella typhimuriumtester strains TA 98, TA 100, TA 1535 and TA 1537 andEscherichia coliWP2uvrA. The plate incorporation test with and without addition of liver S9 mix from rats pre-treated with β-Naphthoflavone/Phenobarbitalwas used. In this study, two experimental series were performed. The S9 mix used contained 10% S9 in the 1^stand 20% S9 in the 2^ndseries, respectively. The first experiment was repeated with lower test material concentrations due to the toxicity of the test material .

 

Results

Solvent and positive control treatments were included for all strains. The mean numbers of revertant colonies were all within acceptable ranges for solvent control treatments, or were clearly elevated by positive control treatments, thus, showing the expected reversion properties of all strains and good metabolic activity of the S9 mix used.

Following treatment of all bacteria tester strains with the test material in the absence and presence of S9 mix, no relevant increases in revertant numbers were observed.

 

Conclusion

With and without addition of S9 mix as the external 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

Justification for classification or non-classification

Based on the provided information there is no need to classified according to the EU Regulation (EC) No 1272/2008 on Classification, Labelling and Packaging of Substances and Mixtures.