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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:
weight of evidence
Study period:
1998
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

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:
OECD Guideline 471 (Bacterial Reverse Mutation Assay)
Qualifier:
according to
Guideline:
OECD Guideline 472 (Genetic Toxicology: Escherichia coli, Reverse Mutation Assay)
Qualifier:
according to
Guideline:
EU Method B.13/14 (Mutagenicity - Reverse Mutation Test Using Bacteria)
GLP compliance:
yes
Type of assay:
bacterial reverse mutation assay

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
solid: particulate/powder
Details on test material:
Disperse Red 362

Method

Species / strain
Species / strain / cell type:
S. typhimurium TA 1535, TA 1537, TA 98, TA 100 and E. coli WP2
Metabolic activation:
with and without
Metabolic activation system:
rat liver homogenate
Test concentrations with justification for top dose:
First experiment 25, 125, 625, 3125 and 6250 µg/plate - all strains
Second experiment: 4, 20, 100, 500 and 1000 µg/plate - TA 100
Vehicle / solvent:
Acetonitril
Controlsopen allclose all
Untreated negative controls:
yes
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
other: 2-aminoanthracene
Remarks:
all strains with S9
Untreated negative controls:
yes
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
other: N-methyl-N-nitro-N-nitrosoguanidine
Remarks:
TA1535, TA100 w/o S9
Untreated negative controls:
yes
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
other: 4-nitro-o-phenylendiamine
Remarks:
TA98 w/o S9
Untreated negative controls:
yes
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
9-aminoacridine
Remarks:
TA1537 w/o S9
Untreated negative controls:
yes
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
N-ethyl-N-nitro-N-nitrosoguanidine
Remarks:
E. coli WP2 uvrA w/o S9
Details on test system and experimental conditions:
METHOD OF APPLICATION:
1. Plate incorporation
- Incubation: 37°C 48 to 72 hours

- Triplicate plating


DETERMINATION OF CYTOTOXICITY
- decrease in number of revertants
- clearing or diminuation of background lawn
- reduction of titer
Evaluation criteria:
Positive: dose-related and reproducible increase in number of revertant colonies
- doubling of spontaneous mutation rate in at least one tester strains either with or without S9

Negative: number of revertants are within historical negative control range in two independent experiments

Results and discussion

Test resultsopen allclose all
Species / strain:
E. coli WP2 uvr A
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
cytotoxicity
Vehicle controls validity:
valid
Untreated negative controls validity:
valid
Positive controls validity:
valid
Species / strain:
other: TA1535, TA1537, TA100, TA98
Metabolic activation:
without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
cytotoxicity
Vehicle controls validity:
valid
Untreated negative controls validity:
valid
Positive controls validity:
valid
Species / strain:
other: TA1535, TA100, TA1537, TA98
Metabolic activation:
with
Genotoxicity:
positive
Cytotoxicity / choice of top concentrations:
cytotoxicity
Vehicle controls validity:
valid
Untreated negative controls validity:
valid
Positive controls validity:
valid
Additional information on results:
TEST-SPECIFIC CONFOUNDING FACTORS
- Precipitation: from 500 µg/plate onwards

Applicant's summary and conclusion

Conclusions:
The test substance is mutagenic in the Salmonella typhimurium reverse mutation assay under the experimental conditions chosen here.
Executive summary:

The test substance was tested for its mutagenic potential based on the ability to induce mutations in selected loci of several bacterial strains, i.e. Salmonella typhimurium and Escherichia coli, in a reverse mutation assay.The tester strains Salmonella typhimurium TA 1535, TA 100, TA 1537, TA 98 and E.coli WP2 uvrA were used in the standard plate test.

Dose ranges from 25 to 6250 µg/plate were used in all strains in the first experiment and 4 to 1000 µg/plate in TA 100 in the second experiment with and without metabolic activation.

Solubility: Precipitation of the test substance was found from about 500 µg/plate onwards

Toxicity: A slight decrease in the number of revertants was observed from about 3125 µg/plate onwards

Mutagenicity: An increase in the number of his revertants was observed after the addition of a metabolizing system using the strains TA 1535, TA 100, TA 1537 and TA 98.

Conclusion: According to the results of the present study, the test substance is mutagenic in the Salmonella typhimurium reverse mutation assay under the experimental conditions chosen here.