Registration Dossier

Toxicological information

Genetic toxicity: in vitro

Currently viewing:

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:
2006-01-03 to 2006-02-16
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
comparable to guideline study with acceptable restrictions
Remarks:
Only three strains are tested. However, an expert statement is added in the field "overall remarks" to justify the fact that no further testing is necessary.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2006
Report Date:
2006

Materials and methods

Test guideline
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 471 (Bacterial Reverse Mutation Assay)
Deviations:
yes
Remarks:
Only 3 bacterial strains used, no repeat experiment and limited details on methodology were provided.
GLP compliance:
no
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): T 745
- Substance type: no data
- Physical state: cream-colored powder
- Analytical purity: approx. 100%
- Impurities (identity and concentrations): no data
- Composition of test material, percentage of components: no data
- Isomers composition: no data
- Purity test date: no data
- Lot/batch No.: 00470548RT000745G1B521
- Expiration date of the lot/batch: no data
- Stability under test conditions: no data
- Storage condition of test material: at room temperature in the dark
- Other: no data
Specific details on test material used for the study:
Description: Cream coloured powder
Batch number: 00470548RT000745G1B521
Purity: ca. 100 %
Date received: 2005-12-15
Storage conditions: Room temperature in the dark

Method

Target gene:
histidine locus
Species / strain
Species / strain / cell type:
S. typhimurium, other: TA98, TA100 and TA102
Details on mammalian cell type (if applicable):
not applicable
Additional strain / cell type characteristics:
not specified
Metabolic activation:
with and without
Metabolic activation system:
S9 rat liver homogenate (10% liver S9 in standard co-factors)
Test concentrations with justification for top dose:
0, 0.5, 1.5, 5, 15, 50, 150, 500, 1500 and 5000 µg/plate
Vehicle / solvent:
- Vehicle(s)/solvent(s) used: dimethyl sulfoxide (DMSO)
- Justification for choice of solvent/vehicle: no data
Controlsopen allclose all
Untreated negative controls:
yes
Remarks:
untreated
Negative solvent / vehicle controls:
yes
Remarks:
DMSO
True negative controls:
no
Positive controls:
yes
Positive control substance:
benzo(a)pyrene
Remarks:
With S9: 5 μg/plate for TA98
Untreated negative controls:
yes
Remarks:
untreated
Negative solvent / vehicle controls:
yes
Remarks:
DMSO
True negative controls:
no
Positive controls:
yes
Positive control substance:
other: 1-8-Dihydroxyanthroquinone
Remarks:
With S9: 10 μg/plate for TA102
Untreated negative controls:
yes
Remarks:
untreated
Negative solvent / vehicle controls:
yes
Remarks:
DMSO
True negative controls:
no
Positive controls:
yes
Positive control substance:
other: 2-aminoanthracene
Remarks:
With S9: 1 μg/plate for TA100
Untreated negative controls:
yes
Remarks:
untreated
Negative solvent / vehicle controls:
yes
Remarks:
DMSO
True negative controls:
no
Positive controls:
yes
Positive control substance:
4-nitroquinoline-N-oxide
Remarks:
Without S9: 0.2 μg/plate for TA98
Untreated negative controls:
yes
Remarks:
untreated
Negative solvent / vehicle controls:
yes
Remarks:
DMSO
True negative controls:
no
Positive controls:
yes
Positive control substance:
mitomycin C
Remarks:
Without S9: 0.5 μg/plate for TA102
Untreated negative controls:
yes
Remarks:
untreated
Negative solvent / vehicle controls:
yes
Remarks:
DMSO
True negative controls:
no
Positive controls:
yes
Positive control substance:
N-ethyl-N-nitro-N-nitrosoguanidine
Remarks:
Without S9: 3 μg/plate for TA100
Details on test system and experimental conditions:
METHOD OF APPLICATION: in agar (plate incorporation)

Measured aliquots (0.1 ml) of one of the bacterial cultures were dispensed into sets of test tubes followed by 2.0 ml of molten, trace histidine supplemented, top agar, 0.1 ml of the test material formulation, vehicle or positive control and either 0.5 ml of S9-mix of phosphate buffer. The contents of each test tube were mixed and equally distributed onto the surface of Vogel-Bonner Minimal agar plates (one tube per plate). This procedure was repeated, in triplicate, for each bacterial strain and for each concentration of the test material both with and without S9-mix.

DURATION
- Exposure duration: 3 days
- Selection time (if incubation with a selection agent): 3 days - simultaneous with exposure

SELECTION AGENT (mutation assays): histidine

NUMBER OF REPLICATIONS: triplicates

DETERMINATION OF CYTOTOXICITY:
- Method: reduction in the growth of the bacterial lawn
Evaluation criteria:
no data
Statistics:
no data

Results and discussion

Test results
Species / strain:
S. typhimurium, other: TA98, TA100 and TA102
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
Additional information on results:
TEST-SPECIFIC CONFOUNDING FACTORS:
- Evaporation from medium: no data
- Water solubility: no data
- Precipitation: No test substance precipitate was observed on the plates at any of the doses tested with or without metabolic activation.

RANGE-FINDING/SCREENING STUDIES: no data

COMPARISON WITH HISTORICAL CONTROL DATA:
The vehicle control plates gave counts of revertant colonies within the normal range. All of the positive control substances used in the test induced marked increases in the frequency of revertant colonies, both with and without metabolic activation. Thus, the sensitivity of the assay and the efficacy of the S9 mix
were validated. Results for negative controls (spontaneous mutation rates) were considered to be acceptable.

ADDITIONAL INFORMATION ON CYTOTOXICITY:
The test material caused a visible reduction in the growth of the bacterial background lawn and/or a subtantial decrease in the frequency of revertant colonies of all the tester strains, initially at 1500 µg/plate.

Applicant's summary and conclusion

Conclusions:
Interpretation of results :
negative with and without metabolic activation

The test substance was considered to be non-mutagenic under the conditions of this test with and without metabolic activation.