Registration Dossier

Toxicological information

Genetic toxicity: in vitro

Currently viewing:

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:
September 30, 1992 - October 30, 1992
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: see 'Remark'
Remarks:
This study has been performed according to OECD 471 (1983), EU Method B.14 (1984) and according to GLP principles. The study was not conducted with E.coli and/or with S. typhimurium TA102, which have an AT base pair at the primary reversion site, as currently required. This study is therefore considered a Salmonella typhimurium reverse mutation assay only. Limited information available to verify the composition of the used test substance.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1992
Report Date:
1992

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
OECD Guideline 471 (Bacterial Reverse Mutation Assay)
Version / remarks:
(1983)
Deviations:
no
Qualifier:
according to
Guideline:
other: EU Method B.14 (1984)
Deviations:
no
Principles of method if other than guideline:
As OECD 471 (1983) required to test Salmonella typhimurium TA1535, TA1537, TA98 and TA100 only, there is no deviation from the guideline.
GLP compliance:
yes (incl. certificate)
Type of assay:
other: Salmonella typhimurium reverse mutation assay (Ames test)

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Name of test material (as cited in study report): KY-ET
- Appearance: Light yellow solid
- Storage condition of test material: At room temperature

Method

Target gene:
Histidine
Species / strain
Species / strain / cell type:
S. typhimurium TA 1535, TA 1537, TA 98 and TA 100
Metabolic activation:
with and without
Metabolic activation system:
Rat liver S9-mix induced by Aroclor 1254 in olive oil
Test concentrations with justification for top dose:
Experiment 1:
Preliminary test (without and with S9) TA98 and TA100: 3.3, 10, 33.3, 100, 333.3, 1000, 2500 and 5000 µg/plate
Main study: TA1535, TA1537:
Without and with S9-mix: 33.3, 100, 333.3, 1000, 2500 and 5000 µg/plate
Experiment 2:
Without and with S9-mix: 33.3, 100, 333.3, 1000, 2500 and 5000 µg/plate
Vehicle / solvent:
- Vehicle(s)/solvent(s) used: DMSO
- Justification for choice of solvent/vehicle: because of its solubility properties
Controls
Untreated negative controls:
yes
Negative solvent / vehicle controls:
yes
Positive controls:
yes
Positive control substance:
other: see the section "Any other information on materials and methods incl. tables"
Details on test system and experimental conditions:
METHOD OF APPLICATION: in agar (plate incorporation)

DURATION
- Exposure duration: 48 hour

NUMBER OF REPLICATIONS:
- Doses of the test substance were tested in triplicate in each strain. Two independent experiments were conducted.

DETERMINATION OF CYTOTOXICITY
- Method: The reduction in the number of spontaneous revertants, a clearing of the bacterial background lawn or by degree of survival of treated cultures

OTHER EXAMINATIONS:
- The presence of precipitation of the test compound on the plates was determined.
Evaluation criteria:
- A test article is considered as positive if either a dose related increase in the number of revertants or a significant and reproducible increase for at least one test concentration is induced.
- A test article producing neither a dose related increase in the number of revertants nor a significant and reproducible positive response at any one of the test points is considered non-mutagenic in this system.
- A significant response is described as follows: A test article is considered as mutagenic if in strain TA100 the number of reversions is at least twice as high and in strains TA1535, TA1537 and TA98 it is at least 3 times higher as compared to the spontaneous reversion rate.
- Also, a dose-dependent increase in the number of revertants is regarded as an indication of possibly existing mutagenic potential of the test article regardless whether the highest dose induced the above described enhancement factors or not.

Results and discussion

Test results
Species / strain:
S. typhimurium TA 1535, TA 1537, TA 98 and TA 100
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
no cytotoxicity
Vehicle controls validity:
valid
Untreated negative controls validity:
valid
Positive controls validity:
valid
Additional information on results:
TEST-SPECIFIC CONFOUNDING FACTORS
- Precipitation: Precipitation was observed only in the top dose of 5000 µg/plate

RANGE-FINDING/SCREENING STUDIES:
- No toxicity or mutagenicity was observed up to and including the top dose of 5000 µg/plate

COMPARISON WITH HISTORICAL CONTROL DATA: No data

ADDITIONAL INFORMATION ON CYTOTOXICITY:
- No toxicity or mutagenicity was observed up to and including the top dose of 5000 µg/plate

Applicant's summary and conclusion

Conclusions:
Interpretation of results (migrated information):
negative

The substance is not mutagenic in the Salmonella typhimurium reverse mutation assay.
Executive summary:

The genetic toxicity of the substance was assessed at concentrations of ≤ 5000 µg/plate using S. typhimurium TA100, TA1535, TA98 and TA1537 strains, in accordance with OECD 471 (1983), EU Method B.14 (1984) and according to GLP principles.

All bacterial strains showed negative responses with and without metabolic activation. The study was not conducted with E.coli and/or with S. typhimurium TA102, which have an AT base pair at the primary reversion site, as currently required. Based on the results of this study, the substance is not mutagenic in the Salmonella typhimurium reverse mutation assay.