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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:
September 25 - October 15, 2007
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: The study has been performed according to OECD and EC guidelines and according to GLP principles.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2008
Report Date:
2008

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
OECD Guideline 471 (Bacterial Reverse Mutation Assay)
Deviations:
no
Qualifier:
according to
Guideline:
EU Method B.13/14 (Mutagenicity - Reverse Mutation Test Using Bacteria)
Deviations:
no
GLP compliance:
yes (incl. certificate)
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): Corsair Clear #34
- Substance type: Clear white lumpy solid
- Physical state: Solid
- Stability under test conditions: Stable
- Storage condition of test material: At room temperature in the dark

Method

Target gene:
Histidine gene in S. typhimurium
Tryptophan gene in E. coli
Species / strainopen allclose all
Species / strain / cell type:
S. typhimurium TA 1535, TA 1537, TA 98 and TA 100
Species / strain / cell type:
E. coli WP2 uvr A
Metabolic activation:
with and without
Metabolic activation system:
phenobarbital and ß-naphthoflavone induced rat liver S9 mix
Test concentrations with justification for top dose:
Preliminary test: 3-10-33-100-333-1000-3330-5000 µg/plate
First and second test: 3-10-33-100-333 µg/plate
Vehicle / solvent:
- Vehicle(s)/solvent(s) used: ethanol
- Justification for choice of solvent/vehicle: test substance is soluble in ethanol after being ground and treated with ultrasonic waves.
Controlsopen allclose all
Untreated negative controls:
yes
Remarks:
ethanol
Positive controls:
yes
Positive control substance:
sodium azide
Remarks:
without S9 mix

Migrated to IUCLID6: 5 µg/plate in saline for TA1535
Positive control substance:
9-aminoacridine
Remarks:
without S9 mix

Migrated to IUCLID6: 60 µg/plate in milli-Q water for TA1537
Positive control substance:
2-nitrofluorene
Remarks:
without S9 mix

Migrated to IUCLID6: 10 µg/plate in DMSO for TA98
Positive control substance:
methylmethanesulfonate
Remarks:
without S9 mix

Migrated to IUCLID6: 650 µg/plate in DMSO for TA100
Positive control substance:
4-nitroquinoline-N-oxide
Remarks:
without S9 mix

Migrated to IUCLID6: 10 µg/plate in DMSO for WP2 uvr A
Positive control substance:
other: 2-aminoanthracene in DMSO (5 and/or 10%) for all tester strains
Remarks:
with S9 mix
Details on test system and experimental conditions:
METHOD OF APPLICATION: in agar (plate incorporation);

DURATION
- Exposure duration: 48 h

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 of the bacterial background lawn, the increase in the size of the microcolonies and the reduction of the revertant colonies

OTHER EXAMINATIONS:
- Other: precipitation of test substance


Evaluation criteria:
A test substance is considered negative (not mutagenic) in the test if:
a) The total number of revertants in tester strain TA100 is not greater than two (2) times the concurrent control, and the total number of revertants in tester strains TA1535, TA1537, TA98 or WP2uvrA is not greater than three (3) times the concurrent control.
b) The negative response should be reproducible in at least one independently repeated experiment.

A test substance is considered positive (mutagenic) in the test if:
a) The total number of revertants in tester strain TA100 is greater than two (2) times the concurrent control, or the total number of revertants in tester strains TA1535, TA1537, TA98 or WP2uvrA is greater than three (3) times the concurrent control.
b) In case a positive response will be repeated, the positive response should be reproducible in at least one independently repeated experiment.

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:
no cytotoxicity, but tested up to precipitating concentrations
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:
no cytotoxicity, but tested up to precipitating concentrations
Untreated negative controls validity:
valid
Positive controls validity:
valid
Additional information on results:
TEST-SPECIFIC CONFOUNDING FACTORS
- Precipitation: slight precipitation was observed at doses of 333 µg/plate and higher.

RANGE-FINDING/SCREENING STUDIES:
No toxicity and mutagenicity was observed up to concentrations of 5000 µg/plate

COMPARISON WITH HISTORICAL CONTROL DATA:
The negative and strain-specific positive control values were within the laboratory historical control data ranges indicating that the test conditions were adequate and that the metabolic activation system functioned properly.

Applicant's summary and conclusion

Conclusions:
Interpretation of results (migrated information):
negative

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 negative and strain-specific positive control values were within our laboratory historical control data ranges indicating that the test conditions were adequate and that the metabolic activation system functioned properly.
Based on the results of this study it is concluded that Corsair Clear #34 is not mutagenic in the Salmonella typhimurium reverse mutation assay and in the Escherichia coli reverse mutation assay.