Registration Dossier

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:
04 December, 2014 - 15 December, 2014
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: The study has been performed according to OECD and/or EC guidelines and according to GLP principles.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2015
Report Date:
2015

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
OECD Guideline 471 (Bacterial Reverse Mutation Assay)
Version / remarks:
(1997)
Deviations:
no
Qualifier:
according to
Guideline:
EU Method B.13/14 (Mutagenicity - Reverse Mutation Test Using Bacteria)
Version / remarks:
(2008)
Deviations:
no
GLP compliance:
yes
Type of assay:
bacterial reverse mutation assay

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
other: liquid
Details on test material:
- Name of test material (as cited in study report): NS-1000
- Appearance: Clear colourless liquid

Method

Target gene:
- S. typhimurium: Histidine gene
- E. coli: Tryptophan gene
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:
Rat liver S9-mix induced by Aroclor 1254 (500 mg/kg).
Test concentrations with justification for top dose:
Experiment 1
Preliminary test (without and with S9) TA100 and WP2uvrA: 1.7, 5.4, 17, 52, 164, 512, 1600 and 5000 µg/plate
Main study: TA1535, TA1537 and TA98:
With and without and with S9-mix: 52, 164, 512, 1600 and 5000 µg/plate
Experiment 2: All 5 strains:
With and without and with S9-mix: 492, 878, 1568, 2800 and 5000 µg/plate
Vehicle / solvent:
- Solvent used: ethanol
- Justification for choice of solvent: Test compound was stable in ethanol and ethanol has been accepted and approved by authorities and international guidelines.
Controlsopen allclose all
Untreated negative controls:
no
Negative solvent / vehicle controls:
yes
Remarks:
ethanol
Positive controls:
yes
Positive control substance:
methylmethanesulfonate
Remarks:
without S9

Migrated to IUCLID6: 650 µg/plate in DMSO for TA100
Untreated negative controls:
no
Negative solvent / vehicle controls:
yes
Remarks:
ethanol
Positive controls:
yes
Positive control substance:
other: 2-nitrofluorene 10 µg/plate in DMSO for TA98
Remarks:
without S9
Untreated negative controls:
no
Negative solvent / vehicle controls:
yes
Remarks:
ethanol
Positive controls:
yes
Positive control substance:
other: ICR-191 2.5 µg/plate in DMSO for TA1537
Remarks:
without S9
Untreated negative controls:
no
Negative solvent / vehicle controls:
yes
Remarks:
ethanol
Positive controls:
yes
Positive control substance:
4-nitroquinoline-N-oxide
Remarks:
without S9

Migrated to IUCLID6: 10 µg/plate in DMSO for WP2uvrA
Untreated negative controls:
no
Negative solvent / vehicle controls:
yes
Remarks:
ethanol
Positive controls:
yes
Positive control substance:
sodium azide
Remarks:
without S9

Migrated to IUCLID6: 5 µg/plate in saline for TA1535
Untreated negative controls:
no
Negative solvent / vehicle controls:
yes
Positive controls:
yes
Positive control substance:
other: 2-aminoanthracene in DMSO for all tester strains
Remarks:
with S9
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.

NUMBER OF CELLS EVALUATED: 10E8 per plate

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:
- The presence of precipitation of the test compound on the plates was determined.
Evaluation criteria:
A test substance is considered negative (not mutagenic) in the test if:
a) The total number of revertants in the 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 vehicle control.
b) The negative response should be reproducible in at least one follow-up experiment.

A test substance is considered positive (mutagenic) in the test if:
a) The total number of revertants in the 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 vehicle control.
b) In case a follow up experiment is performed when a positive response is observed in one of the tester strains, the positive response should be reproducible in at least one follow up 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 nor precipitates, but tested up to recommended limit concentrations
Remarks:
up to and including 5000 μg/plate
Vehicle 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 nor precipitates, but tested up to recommended limit concentrations
Remarks:
up to and including 5000 μg/plate
Vehicle controls validity:
valid
Positive controls validity:
valid
Additional information on results:
TEST-SPECIFIC CONFOUNDING FACTORS
- Precipitation: No precipitation was observed up to and including 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:
- 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.

ADDITIONAL INFORMATION ON CYTOTOXICITY:
In experiment 2, cytotoxicity was only observed in tester strain TA100 in the presence of S9-mix, where a slight reduction in the number of the revertant colonies was observed at the highest tested concentration of 5000 µg/plate. There was no reduction in the bacterial background lawn and no biologically relevant decrease in the number of revertants up to and including the top dose of 5000 µg/plate in all other tester strains in the absence and presence of S9-mix.

Applicant's summary and conclusion

Conclusions:
Interpretation of results (migrated information):
negative

In an AMES test, performed according to OECD 471 guideline and GLP principles, NS-1000 was found not to be mutagenic with or without metabolic activation.
Executive summary:

An AMES test with NS-1000 was performed according to OECD 471 guideline and GLP principles. All bacterial strains showed negative responses up to and including 5000 µg/plate in two independent experiments, i.e. no significant dose-related increase in the number of revertants with or without metabolic activation was seen. No precipitation of the test substance was observed. In experiment 2, cytotoxicity was only observed in tester strain TA100 in the presence of S9-mix, where a slight reduction in the number of the revertant colonies was observed at the highest tested concentration of 5000 µg/plate. There was no reduction in the bacterial background lawn and no biologically relevant decrease in the number of revertants up to and including the top dose of 5000 µg/plate in all other tester strains in the absence and presence of S9-mix. 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.

Based on the results of this study it is concluded that NS-1000 is not mutagenic in the Salmonella typhimurium reverse mutation assay and in the Escherichia coli reverse mutation assay with or without metabolic activation.