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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:
January 7, 1991 - June 26, 1991
Reliability:
1 (reliable without restriction)

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1991
Report Date:
1991

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
EU Method B.13/14 (Mutagenicity - Reverse Mutation Test Using Bacteria)
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 471 (Bacterial Reverse Mutation Assay)
GLP compliance:
yes
Type of assay:
bacterial reverse mutation assay

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Name of test material (as cited in study report): NBDI
- Physical state: liquid

Method

Target gene:
- S. typhimurium: Histidine gene
- E. coli: Tryptophan gene
Species / strainopen allclose all
Species / strain / cell type:
E. coli WP2 uvr A
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 a combination of phenobarbital and 5,6-benzoflavone
Test concentrations with justification for top dose:
The preliminary test was carried out at 8 doses of 39 to 5000 µg/plate
Main study:
With metabolic activation: 39; 78; 156; 313; 625, 1250 and 2500 µg/plate
Without metabolic activation: 20; 39; 78; 156; 313, 625 and 1250 µg/plate
Vehicle / solvent:
DMSO
Controls
Untreated negative controls:
yes
Negative solvent / vehicle controls:
yes
Remarks:
DMSO
Positive controls:
yes
Remarks:
(see below)
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.
Evaluation criteria:
A test substance is considered negative (not mutagenic) in the test if the total number of revertants in the tester strains is not greater than two (2) times the concurrent negative controls.

Results and discussion

Test resultsopen allclose all
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:
cytotoxicity
Remarks:
(in all strains +/- S9 but starting at different concentration)
Vehicle controls validity:
valid
Untreated negative controls validity:
valid
Positive controls validity:
valid
Species / strain:
E. coli WP2 uvr A
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
cytotoxicity
Remarks:
(at 2500 µg/plate)
Vehicle controls validity:
valid
Untreated negative controls validity:
valid
Positive controls validity:
valid
Additional information on results:
COMPARISON WITH HISTORICAL CONTROL DATA:
- The negative (non-treatment and solvent) control values were within the laboratory historical control data ranges indicating that the test conditions were adequate
ADDITIONAL INFORMATION ON CYTOTOXICITY:
-Toxicity was observed in all strains tested in both experiments

Applicant's summary and conclusion

Conclusions:
A bacterial reverse mutation assay was conducted equivalent to OECD 471 (Ames test) and GLP principles. All bacterial strains showed negative responses over the entire dose range, i.e. no significant dose-related increase in the number of revertants in two independently repeated experiments. The substance is not mutagenic in the Salmonella typhimurium reverse mutation assay and in the Escherichia coli reverse mutation assay.