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Toxicological information

Genetic toxicity: in vitro

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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:
1997-10-31 to 1998-05-29
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: This study is classified as reliable without restriction because it was conducted according to or similar to EU B.13/14 guideline.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1998
Report Date:
1998

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
EU Method B.13/14 (Mutagenicity - Reverse Mutation Test Using Bacteria)
Version / remarks:
Cited as Directive 84/449/EEC, B.14
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 471 (Bacterial Reverse Mutation Assay)
GLP compliance:
yes (incl. certificate)
Remarks:
OECD GLP
Type of assay:
bacterial reverse mutation assay

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
Test compound: TPS 37
Chemical name: di-t-nonyl polysulfide
CAS no.: 68425-16-1
Source: Elf Aquitaine Production
Batch: 47978
Sulfur content: 36.9%.

Method

Target gene:
histidine
Species / strain
Species / strain / cell type:
other: Strains: TA 98, TA 100, TA 1535, TA 1537, TA 102
Metabolic activation:
with and without
Metabolic activation system:
S9 mix
Test concentrations with justification for top dose:
Experiment 1: 8, 40, 200, 1000 and 5000 µg/plate
Experiment 2: 4.883, 19.531, 78.125, 312.5, 1250 and 5000 µg/plate
Vehicle / solvent:
- Vehicle(s)/solvent(s) used: DMF
Controls
Untreated negative controls:
yes
Negative solvent / vehicle controls:
yes
Remarks:
DMF
True negative controls:
yes
Positive controls:
yes
Remarks:
DMSO
Details on test system and experimental conditions:
SYSTEM OF TESTING
- 2 independent trials; in the 1st and 2nd trial without metabolic activation system (MA) the direct plate incorporation method was used; this method also used in the 1st trial with MA, in the 2nd trial with MA the preincubation method (1 h, 37°C). 3 plates per concentration
- Metabolic activation system (MA): S9 fraction from liver homogenates of rats induced with 500 mg/kg Aroclor 1254
- solvent: dimethylformamide
- Controls: . solvent control (with and without MA)
. Positives controls:
- Without S9
TA98: 2-nitrofluorene 5.0 µg/plate
TA100 and TA1535: Sodium azide 2.0 µg/plate
TA1537: 9-aminoacridine 50 µg/plate
TA102: glutaraldehyde 25 µg/plate
- With S9
TA98, TA100 and TA1535: 2-aminoanthracene 5.0 µg/plate
. sterility control checked during the test.
- Concentrations:
Experiment 1: 8, 40, 200, 1000 and 5000 µg/plate
Experiment 2: 4.883, 19.531, 78.125, 312.5, 1250 and 5000 µg/plate
- Cytotoxicity: A preliminary toxicity test was performed to define the concentrations to be used for the mutagenicity study. TA100 exposed to 8-5000 µg/plate with and without MA
Evaluation criteria:
The test article was considered to be mutagenic if:
1. the assay was valid
2. a dose related and reproducible increase in the number of revertants is observed, or a significant and reproducible increase in the number of revertants was induced at one or more test concentration

Results and discussion

Test results
Species / strain:
other: Strains: TA 98, TA 100, TA 1535, TA 1537, TA 102
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
other: >= 1250 µg/plate
Vehicle controls validity:
valid
Untreated negative controls validity:
valid
Positive controls validity:
valid
Additional information on results:
Evidence of toxicity was observed at >=1250 µg/plate in only a few test strains. Precipitation of test agent was observed on all plates treated at concentrations >= 1000  µg/plate.

The mean numbers of revertant colonies on negative control plates all fell within acceptable ranges, and were significantly elevated by positive control treatments.

No TPS 37 treatment of any of the test strains produced an increase in revertant numbers sufficient to be considered as indicative of mutagenic activity.
Remarks on result:
other: strain/cell type: Strains: TA 98, TA 100, TA 1535, TA 1537, TA 102
Remarks:
Migrated from field 'Test system'.

Applicant's summary and conclusion

Conclusions:
Interpretation of results (migrated information):
negative

TPS 37 did not induce mutation in five strains of Salmonella typhimurium (TA98, TA100, TA1535, TA1537 and TA102), when tested under the conditions employed for this study, which included treatments up to 5000 µg/plate, both in the absence and in the presence of a rat liver metabolic activation system (S-9).
Executive summary:

In a reverse gene mutation assay in bacteria, strains TA98, TA100, TA1535, TA1537 and TA102 of S. typhimurium were exposed to TPS 37 in DMF at concentrations of 8, 40, 200, 1000, and 5000 µg/plate in the presence and absence of mammalian metabolic activation using the Ames test.

 

TPS 37 was tested up to limit concentrations of 5000 µg/plate. Following treatment in experiment 1, evidence of toxicity was observed at the highest dose (5000 µg/plate) treatments in only a few test strains. Precipitation of test agent was observed on all plates treated at concentrations of 1000 and 5000 µg/plate. For experiment 2, dose intervals were narrowed to more closely investigate those concentrations of TPS 37 most likely to induce mutagenic response. All treatments in the presence of S-9 employed a pre-incubation step. Evidence of toxicity was found in the higher test doses in the presence and absence of S-9 mix. Precipitation of test agent was observed on all plates at concentrations of 1250 and 5000 µg/plate. No treatment with TPS 37 of any test strains produced an increase in revertant numbers high enough to be considered characteristic of mutagenic activity. TPS 37 did not induce mutation in five strains of S. typhimurium when tested under study conditions. Conditions included treatments up to 5000 µg/plate and the absence and presence of rat liver activation system.

 

This study received a Kilmisch score of 1 and is classified as reliable without restrictions because it adheres to guidelines and includes testing at the limiting concentration.