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Toxicological information

Genetic toxicity: in vitro

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Administrative data

Endpoint:
in vitro gene mutation study in bacteria
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2017
Report Date:
2017

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
OECD Guideline 471 (Bacterial Reverse Mutation Assay)
Qualifier:
according to
Guideline:
EU Method B.13/14 (Mutagenicity - Reverse Mutation Test Using Bacteria)
Qualifier:
according to
Guideline:
EPA OPPTS 870.5100 - Bacterial Reverse Mutation Test (August 1998)
Principles of method if other than guideline:
No deviation from guideline.
GLP compliance:
yes (incl. certificate)
Type of assay:
bacterial reverse mutation assay

Test material

Reference
Name:
Unnamed
Type:
Constituent
Type:
Constituent
Test material form:
liquid
Specific details on test material used for the study:
SOURCE OF TEST MATERIAL
- Supplier: Borica Co., Ltd.
- Lot number: 000577Z
- Expiration date of the lot/batch: 2018-Jul-07
- CAS number: 23519-77-9

Method

Target gene:
Gene of histidine in Salmonella typhimurium and gene of tryptophan in Escherichia coli.
Species / strainopen allclose all
Species / strain / cell type:
S. typhimurium TA 1535, TA 1537, TA 98 and TA 100
Additional strain / cell type characteristics:
other: all with rfa- and deletion of uvr B gene. In strain TA98 and TA100, presence of R factor plasmid pKM101 enhances chemical and UV-induced mutagenesis via an increase in the error-prone repair pathway.
Species / strain / cell type:
E. coli WP2 uvr A
Metabolic activation:
with and without
Metabolic activation system:
rat-liver homogenate activation system (S9)
Test concentrations with justification for top dose:
Eight concentrations of the test item (1.5, 5, 15, 50, 150, 500, 1500 and 5000 µg/plate) were assayed in triplicate against each tester strain, using the direct plate incorporation method.

The maximum concentration used for testing was 5000 µg/plate as the toxicity in Experiment 1 was not severe enough to preclude testing up to
the maximum recommended dose level.
Vehicle / solvent:
Vehicle(s)/solvent(s) used: THF (Tetrahydrofuran)
Supplier: Sigma-Aldrich
Batch number (purity) STBG9857 (99.9%)
Justification for choice of solvent/vehicle: the test substance was immiscible in sterile distilled water, dimethylformamide and dimethyl sulphoxide but was fully miscible in THF at 200 mg/mL. THF therefore was selected as the vehicle.
Controls
Untreated negative controls:
yes
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
4-nitroquinoline-N-oxide
9-aminoacridine
N-ethyl-N-nitro-N-nitrosoguanidine
benzo(a)pyrene
other: 2-Aminoanthracene (2AA)
Details on test system and experimental conditions:
METHOD OF APPLICATION: in medium; in agar (plate incorporation); preincubation;

DURATION
- Preincubation period: 37 +/-3°C for 20 minutes with shaking
- Exposure duration: 37 +/-3°C for 48 hours.

NUMBER OF REPLICATIONS: 3

Evaluation criteria:
There are several criteria for determining a positive result. Any, one, or all of the following can be used to determine the overall result of the study:
1. A dose-related increase in mutant frequency over the dose range tested (De Serres and Shelby, 1979).
2. A reproducible increase at one or more concentrations.
3. Biological relevance against in-house historical control ranges.
4. Statistical analysis of data as determined by UKEMS (Mahon et al., 1989).
5. Fold increase greater than two times the concurrent solvent control for any tester strain (especially if accompanied by an out-of-historical range response (Cariello and Piegorsch, 1996)).

A test item will be considered non-mutagenic (negative) in the test system if the above
criteria are not met.
Statistics:
Statistical significance was confirmed by using Dunnetts Regression Analysis (* = p < 0.05) for those values that indicate statistically significant increases in the frequency of revertant colonies compared to the concurrent solvent control. Values that the program concluded as statistically significant but were within the in-house historical profile were not reported.

Results and discussion

Test resultsopen allclose all
Key result
Species / strain:
S. typhimurium TA 1535
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
Key result
Species / strain:
S. typhimurium TA 1537
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
Key result
Species / strain:
S. typhimurium TA 98
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
Key result
Species / strain:
S. typhimurium 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
Key result
Species / strain:
E. coli WP2 uvr A
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

Applicant's summary and conclusion

Conclusions:
The test substance was considered to be non-mutagenic under the conditions of this test.
Executive summary:

The test substance was tested according to OECD guideline 471 "Bacterial Reverse Mutation Test". Salmonella typhimurium strains TA1535, TA1537, TA98 and TA100 and Escherichia coli strain WP2 uvrA were treated with the test item using both the Ames plate incorporation and pre-incubation methods at up to eight dose levels (1.5, 5, 15, 50, 150, 500, 1500 and 5000 µg/plate), in triplicate, both with and without the addition of a rat liver homogenate metabolizing system (10% liver S9 in standard co-factors).

The test substance was not mutagenic either with or without metabolic activation.