Reaction mass of 2-(2-thienyl)ethyl benzenesulphonate and toluene

Genetic toxicity: in vitro

Administrative data

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:

26 march to 10 may 1999

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Comparable to OECD 471 guideline but report is incomplete and the study is not GLP.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2001

Report date:

2001

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

GLP compliance:

no

Type of assay:

bacterial reverse mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

Reaction mass of 2-(2-thienyl)ethyl benzenesulphonate and toluene

IUPAC Name:

Reaction mass of 2-(2-thienyl)ethyl benzenesulphonate and toluene

Details on test material:

Batch: S3221 (8S 00038)

Method

Target gene:

Histidine

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:

S9-mix (containing 2.5% of S9) from livers of Aroclor 1254-treated rats

Test concentrations with justification for top dose:

Dose-range finding test (TA 98), plate incorporation and preincubation methods: 0, 50, 100, 500, 1000, 2500, 5000 µg/plate with and without metabolic activation.
Mutagenicity test, preincubation method: 0, 100, 500, 1000, 2500, 5000 µg/plate with and without metabolic activation.

Vehicle / solvent:

- Vehicle(s)/solvent(s) used: Dimethyl sulphoxide (DMSO)

Controls

Controls 1

Untreated negative controls:

yes

Remarks:

DMSO (100µL/plate)

Negative solvent / vehicle controls:

yes

Remarks:

DMSO

Positive controls:

yes

Remarks:

Without metabolic activation

Positive control substance:

9-aminoacridine

2-nitrofluorene

sodium azide

mitomycin C

Remarks:

sodium azide: 1µg/plate (TA100, TA1535); 2-nitrofluorene: 2.5 µg/plate (TA98); 9-aminoacridine: 100 µg/plate (TA1537); mitomycin C: 0.25 µg/plate (TA102)

Controls 2

Untreated negative controls:

yes

Remarks:

DMSO (100µL/plate)

Negative solvent / vehicle controls:

yes

Remarks:

DMSO

Positive controls:

yes

Remarks:

With metabolic activation

Positive control substance:

other: 2-aminoanthracene

Remarks:

2-aminoanthracene: 1µg/plate (TA100); 2.5 µg/plate (TA98, TA1535, TA 1537); 5 µg/plate (TA102)

Details on test system and experimental conditions:

METHOD OF APPLICATION: preincubation
Exposure duration: 48h (TA98, TA100, TA1535 and TA1537) and 72h (TA102)
Number of plates/concentration/test: 1 for the dose-range finding study, 3 for the mutagenicity test
Number of independent mutagenicity test: 1

Results and discussion

Test results

Test results 1

Species / strain:

S. typhimurium TA 98

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Remarks:

from 2500 µg/plate upwards

Vehicle controls validity:

valid

Positive controls validity:

valid

Test results 2

Species / strain:

S. typhimurium TA 100

Metabolic activation:

with and without

Genotoxicity:

positive

Remarks:

significant increase in the number of revertants more pronounced without S9-mix and a clear dose-related effect with and without S9-mix

Cytotoxicity / choice of top concentrations:

cytotoxicity

Remarks:

at 5000 µg/plate

Vehicle controls validity:

valid

Positive controls validity:

valid

Test results 3

Species / strain:

S. typhimurium TA 102

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Remarks:

at 5000 µg/plate

Vehicle controls validity:

valid

Positive controls validity:

valid

Test results 4

Species / strain:

S. typhimurium TA 1535

Metabolic activation:

with and without

Genotoxicity:

positive

Remarks:

significant increase in the number of revertants more pronounced without S9-mix and a clear dose-related effect with and without S9-mix

Cytotoxicity / choice of top concentrations:

cytotoxicity

Remarks:

from 500 µg/plate upwards with S9-mix and from 2500 µg/plate upwards without S9-mix

Vehicle controls validity:

valid

Positive controls validity:

valid

Test results 5

Species / strain:

S. typhimurium TA 1537

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Remarks:

at 5000 µg/plate

Vehicle controls validity:

valid

Positive controls validity:

valid

Additional information on results:

RANGE-FINDING/SCREENING STUDIES: Precipitation was noted from 1000 µg/plate upwards without S9-mix and with the plate incorporation method and at 5000 µg/plate with S9-mix and the preincubation method.
No toxic effects were noted with the plate incorporation method whether with or without S9-mix or with the preincubation method with S9-mix; only moderate toxicity was reported at 5000 µg/plate without S9-mix with the preincubation method. Consequently, 5000 µg/plate was chosen as the top dose to conduct the mutagenicity study as it is the maximum dose recommended by international regulations and the preincubation method was selected since it is considered to be more sensitive.

Applicant's summary and conclusion

Conclusions:

Interpretation of results (migrated information):
positive

BTE in toluene showed a mutagenic activity with and without S9-mix in the bacterial reverse mutation test in TA 1535 and TA 100, two Salmonella typhimurium strains that detect base-pair substitution mutagens.