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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:
The experimental phase of this study was performed between 31 July 2007 and 27 August 2007 .
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: GLP guideline study.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2007
Report date:
2007

Materials and methods

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

Test material

Constituent 1
Reference substance name:
Reaction mass of N,N’-bis-(3-methoxypropyl)-C22(branched)-alkyldiamide and N,N’-bis-(3-methoxypropyl)-C17(branched)-alkyldiamide
EC Number:
940-953-8
Molecular formula:
not applicable UVCB
IUPAC Name:
Reaction mass of N,N’-bis-(3-methoxypropyl)-C22(branched)-alkyldiamide and N,N’-bis-(3-methoxypropyl)-C17(branched)-alkyldiamide
Test material form:
other: off white waxy solid block

Method

Target gene:
Histidine for Salmonella
Tryptophan for E. Coli
Species / strain
Species / strain / cell type:
other: S. typhimurium TA 1535, TA 1537, TA 98, TA 100 and E. coli WP2uvrA-
Details on mammalian cell type (if applicable):
Not applicable.
Metabolic activation:
with and without
Metabolic activation system:
phenobarbitone/beta­naphthoflavone induced rat liver, S9
Test concentrations with justification for top dose:
Preliminary Toxicity Test: 0, 0.15, 0.5, 1.5, 5, 15, 50, 150, 500, 1500 and 5000 µg/plate
Mutation Test - Experiment 1 (Range-finding Test): 50, 150, 500, 1500 and 5000 µg/plate
Mutation Test - Experiment 2 (Main Test): 50, 150, 500, 1500 and 5000 µg/plate
Vehicle / solvent:
- Vehicle(s)/solvent(s) used: Acetone
- Justification for choice of solvent/vehicle: The test material was insoluble in sterile distilled water and dimethyl sulphoxide at 50 mg/ml but was fully soluble in acetone at the same concentration in solubility checks performed in-house. Acetone was therefore selected as the vehicle.

The test material was accurately weighed and approximate half-log dilutions prepared in acetone by mixing on an autovortex mixer and sonication for approximately 1 minute at room temperature on the day of each experiment. Prior to use, the solvent was dried using molecular sieves (sodium alumino-silicate) ie 2 mm pellets with a nominal pore diameter of 4 x 10-4 microns.
Controls
Untreated negative controls:
yes
Remarks:
Spontaneous mutation rates
Negative solvent / vehicle controls:
yes
Remarks:
Acetone
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)
Remarks:
Postive control substances used without S9-mix: N-ethyl-N-nitro-N-nitrosoguanidine (ENNG), 9-Aminoacridine (9AA), 4-Nitroquinoline-1-oxide (4NQO); Positive control substances with S9-mix: 2-Aminoanthracene (2AA), Benzo(a)pyrene (BP)
Details on test system and experimental conditions:
METHOD OF APPLICATION: in agar (plate incorporation).

DURATION
- Preincubation period for bacterial strains: 10h
- Exposure duration: 48 hrs
- Expression time (cells in growth medium): Not applicable
- Selection time (if incubation with a selection agent): Not applicable

NUMBER OF REPLICATIONS: Triplicate plating.

DETERMINATION OF CYTOTOXICITY
- Method: plates were assessed for numbers of revertant colonies and examined for effects on the growth of the bacterial background lawn.
Evaluation criteria:
Acceptance Criteria:
The reverse mutation assay may be considered valid if the following criteria are met:
-All tester strain cultures should exhibit a characteristic number of spontaneous revertants per plate in the vehicle and untreated controls.
- The appropriate characteristics for each tester strain have been confirmed, eg rfa cell-wall mutation and pKM101 plasmid R-factor.
-All tester strain cultures should be in the approximate range of 1 to 9.9 x 10E9 bacteria per ml.
- Each mean positive control value should be at least twice the respective vehicle control value for each strain, thus demonstrating both the intrinsic sensitivity of the tester strains to mutagenic exposure and the integrity of the S9-mix.
-There should be a minimum of four non-toxic test material dose levels.
-There should not be an excessive loss of plates due to contamination.

Evaluation Criteria:
There are several criteria for determining a positive result, such as a dose-related increase in revertant frequency over the dose range tested and/or a reproducible increase at one or more concentrations in at least one bacterial strain with or without metabolic activation. Biological relevance of the results will be considered first, statistical methods, as recommended by the UKEMS can also be used as an aid to evaluation, however, statistical significance will not be the only determining factor for a positive response.

A test material will be considered non-mutagenic (negative) in the test system if the above criteria are not met.

Results and discussion

Test results
Species / strain:
other: S. typhimurium TA 1535, TA 1537, TA 98, TA 100 and E. coli WP2uvrA-
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
no cytotoxicity nor precipitates, but tested up to recommended limit concentrations
Vehicle controls validity:
valid
Untreated negative controls validity:
valid
Positive controls validity:
valid
Additional information on results:
PRELIMINARY TOXICITY TEST:
The test material was non-toxic to the strains of bacteria used (TA100 and WP2uvrA-). The test material formulation and S9-mix used in this experiment were both shown to be sterile.

MUTATION TEST:
Prior to use, the master strains were checked for characteristics, viability and spontaneous reversion rate (all were found to be satisfactory). The amino acid supplemented top agar and the S9-mix used in both experiments was shown to be sterile.

Results for the negative controls (spontaneous mutation rates) are presented in Table 1 (see attached background material) and were considered to be acceptable. These data are for concurrent untreated control plates performed on the same day as the Mutation Test.

The individual plate counts, the mean number of revertant colonies and the standard deviations for the test material, vehicle and positive controls both with and without metabolic activation, are presented in Table 2 to Table 5 (see attached background material).

The test material caused no visible reduction in the growth of the bacterial background lawn at any dose level. The test material was, therefore, tested up to the maximum recommended dose level of 5000 µg/plate. A globular precipitate was observed, with the aid of a microscope, at and above 1500 µg/plate, becoming visible by eye at 5000 µg/plate. This did not prevent the scoring of revertant colonies.

No significant increases in the frequency of revertant colonies were recorded for any of the bacterial strains, at any dose level either with or without metabolic activation.

All of the positive control chemicals used in the test induced marked increases in the frequency of revertant colonies thus confirming the activity of the S9-mix and the sensitivity of the bacterial strains.








Remarks on result:
other: all strains/cell types tested
Remarks:
Migrated from field 'Test system'.

Applicant's summary and conclusion

Conclusions:
Interpretation of results (migrated information):
negative

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

Introduction.

The method was designed to conform to the guidelines for bacterial mutagenicity testing published by the major Japanese Regulatory Authorities including METI, MHLW and MAFF. It also meets the requirements of the OECD Guidelines for Testing of Chemicals No. 471 "Bacterial Reverse Mutation Test", Method B13/14 of Commission Directive 2000/32/EC and the USA, EPA (TSCA) OPPTS harmonised guidelines.

Methods.

Salmonella typhimurium strains TA1535, TA1537, TA98 and TA100 and Escherichia coli strain WP2uvrA- were treated with solutions of the test material using the Ames plate incorporation method at five dose levels, in triplicate, both with and without the addition of a rat liver homogenate metabolising system (l0% liver S9 in standard co-factors). The dose range for the range-finding test was determined in a preliminary toxicity assay and was 50 to 5000 µg/plate.

The experiment was repeated on a separate day using the same dose range as the range-finding test, fresh cultures of the bacterial strains and fresh test material formulations.

Results.

The vehicle (acetone) control plates gave counts of revertant colonies within the normal range. All of the positive control chemicals used in the test induced marked increases in the frequency of revertant colonies, both with or without metabolic activation. Thus, the sensitivity of the assay and the efficacy of the S9-mix were validated.

The test material caused no visible reduction in the growth of the bacterial background lawn at any dose level. The test material was, therefore, tested up to the maximum recommended dose level of 5000 µg/plate. This did not prevent the scoring of revertant colonies.

No significant increases in the frequency of revertant colonies were recorded for any of the bacterial strains, with any dose of the test material, either with or without metabolic activation.

Conclusion.

The test material was considered to be non-mutagenic under the conditions of this test.