Propanoic acid, 2-[(ethoxythioxomethyl)thio]-, methyl ester

Endpoint summary

Key value for chemical safety assessment

Genetic toxicity in vitro

Description of key information

Mutagenicity - Reverse Mutation Test Using Bacteria : negative (TNO, 2000)

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:

2000

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Deviations:

no

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Type of assay:

bacterial reverse mutation assay

Target gene:

Histidine or tryptophan gene

Species / strain / cell type:

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

Species / strain / cell type:

E. coli WP2 uvr A

Metabolic activation:

with and without

Metabolic activation system:

S9 mix induced with Aroclor 1254

Test concentrations with justification for top dose:

Assay 1: 62, 185, 556, 1667 and 5000 µg/plate with and without metabolic activation.
Assay 2: 63, 125, 250, 500 and 1000 µg/plate with and without metabolic activation.

Vehicle / solvent:

DMSO was chosen as vehicle for the assays and the test substance was dissolved at 50 mg/ml in the first assay and at 10 mg/ml in the second assay. At 50 mg/ml and 10 mg/ml the test substance in DMSO resulted in a light-yellow clear solution. Thereafter, serial dilutions of the test substance in DMSO were prepared.

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

9-aminoacridine

2-nitrofluorene

sodium azide

benzo(a)pyrene

other: 2-aminoanthracene, N-ethyl-N-nitrosourea

Details on test system and experimental conditions:

METHOD OF APPLICATION: in agar (plate incorporation) with and without metabolic activation and in the first and second assays

DURATION
- Exposure duration: 3 days at 37°C

NUMBER OF REPLICATIONS: 3

DETERMINATION OF CYTOTOXICITY - Method: other: reduction in number of revertant colonies per plate and/or a clearing of the background lawn of bacterial growth.

Evaluation criteria:

A response is considered to be positive if the mean number of revertant colonies on the test plates is increased two-fold or more compared to that on the negative control plates.
A test substance is considered to be mutagenic if a concentration-related increase or if a reproducible positive response is observed.

Statistics:

No statistical analysis is performed.

Key result

Species / strain:

S. typhimurium TA 1535

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Remarks:

1667 - 5000 µg/plate

Vehicle controls validity:

valid

Untreated negative controls validity:

not applicable

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

Remarks:

1667 - 5000 µg/plate

Vehicle controls validity:

valid

Untreated negative controls validity:

not applicable

Positive controls validity:

valid

Key result

Species / strain:

S. typhimurium TA 98

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Remarks:

1667 - 5000 µg/plate

Vehicle controls validity:

valid

Untreated negative controls validity:

not applicable

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

Remarks:

1667 - 5000 µg/plate

Vehicle controls validity:

valid

Untreated negative controls validity:

not applicable

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

Remarks:

1667-5000 µg/plate

Vehicle controls validity:

valid

Untreated negative controls validity:

not applicable

Positive controls validity:

valid

Key result

Species / strain:

S. typhimurium TA 98

Metabolic activation:

without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Remarks:

500 µg/plate

Vehicle controls validity:

valid

Untreated negative controls validity:

not applicable

Positive controls validity:

valid

Key result

Species / strain:

S. typhimurium TA 1535

Metabolic activation:

without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Remarks:

1000 μg/plate

Vehicle controls validity:

valid

Untreated negative controls validity:

not applicable

Positive controls validity:

valid

Species / strain:

S. typhimurium TA 1537

Metabolic activation:

without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Remarks:

1000 μg/plate

Vehicle controls validity:

valid

Untreated negative controls validity:

not applicable

Positive controls validity:

valid

Species / strain:

S. typhimurium TA 98

Metabolic activation:

without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Remarks:

1000 μg/plate

Vehicle controls validity:

valid

Untreated negative controls validity:

not applicable

Positive controls validity:

valid

Species / strain:

S. typhimurium TA 100

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Remarks:

1000 μg/plate

Vehicle controls validity:

valid

Untreated negative controls validity:

not applicable

Positive controls validity:

valid

Additional information on results:

In both assays, in the absence and the presence of the S9-mix and in ail strains, Rhodixan A-1 did not cause a two-fold or greater increase in the mean number of revertant colonies appearing in the test plates compared to the background spontaneous reversion rate observed with the negative control, and did not give evidence of a dose-response relationship.
The mean number of his + and trp+ revertant colonies of the negative controls were within the acceptable range, and the positive controls gave the expected increase in the mean number of revertant colonies.

Remarks on result:

other: first assay

Conclusions:

Rhodixan A-1 in Salmonella typhimurium strains TA 1535, TA 1537, TA 98 and TA 100, and in the Escherichia coli strain WP2 uvrA, in both the absence and the presence of the S9-mix, was not mutagenic under the
conditions employed in this study.

Executive summary:

The mutagenic potential of RHODIXAN A-1 was assessed in Salmonella typhimurium, according to EC method B.13-B.14 and modified O.E.C.D. guideline 471, and in compliance with Good Laboratory Practice.

The histidine-requiring S. typhimurium mutants TA 1535, TA 1537, TA 98, TA 100 and the tryptophan-requiring Escherichia coli mutant WP2 uvrA were used in the presence and the absence of metabolic activation system from the liver fraction of Aroclor 1254-induced rats (S9-mix).

The test article was dissolved in DMSO, and dose levels used were 62, 185, 556, 1667 and 5000 µg/plate in the first assay, and 63, 125, 250, 500 and 1000 µg/plate in the second assay, with and without S9-mix. All determinations were made in triplicate. Simultaneous negative (solvent) and positive controls were used in all experiments.

 

In the first assay, cytotoxicity was observed in all strains in the absence and in the presence of S-9 mix at the concentrations 1667-5000 µg/plate. In the second assay, cytotoxicity was observed at 500 µg/plate in TAthe absence of S-9 mix, and at 1000 µg/plate in TA1535, TA1537, TA100, and TA98, in the absence of S-9 mix. Cytotoxicity was also observed in TA100 in the presence of S-9 mix, at 1000 µg/plate.

There was no increase in the mean number of revertant colonies, with or without S9-mix in any of the bacterial strains tested. Positive controls gave the expected increases in the number of revertants, with and without S-9 mix.

 

Under the conditions of this study,RHODIXAN A-1did not demonstrate anyin vitromutagenic activity in these bacterial test systems.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (negative)

Additional information

In vitro

Bacterial gene mutation:

One fully reliable study is available (TNO, 2000) conducted according to OECD 471 and GLP. Rhodixan A-1 in Salmonella typhimurium strains TA 1535, TA 1537, TA 98 and TA 100, and in the Escherichia coli strain WP2 uvrA, in both the absence and the presence of the S9-mix, was not mutagenic under the conditions employed in this study.

Justification for classification or non-classification

Harmonized classification:

No harmonized classification is available according to the Regulation (EC) No 1272/2008.

Self-classification:

Considering the results in in vitro test, the substance is therefore not regarded to have mutagenic effects and does not require classification for genetic toxicity according to the Regulation (EC) 1272/2008.