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Toxicological information

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:
18 August to 6 September 1999
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: The study was conducted in a GLP compliant laboratory according to accepted regulatory guidelines

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1999
Report Date:
1999

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
Type of assay:
bacterial reverse mutation assay

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
semi-solid (amorphous): gel
Remarks:
migrated information: paste
Details on test material:
- Name of test material (as cited in study report): S-900
- Physical state: dark brown paste
- Analytical purity: 98.72%
- Lot/batch No.: 02869
- Storage condition of test material: room temperature in the dark
- Other:

Method

Species / strain
Species / strain / cell type:
S. typhimurium TA 1535, TA 1537, TA 98, TA 100 and E. coli WP2
Metabolic activation:
with and without
Metabolic activation system:
Phenobarbitone/ß-Naphthoflavone induced, rat-liver S9.
Test concentrations with justification for top dose:
Concentration range in the main test (with metabolic activation): 50 ... 5000 µg/plate
Concentration range in the main test (without metabolic activation): 50 ... 5000 µg/plate
Vehicle / solvent:
Solvent: Acetone
Controls
Negative solvent / vehicle controls:
yes
Positive controls:
yes
Positive control substance:
4-nitroquinoline-N-oxide
9-aminoacridine
N-ethyl-N-nitro-N-nitrosoguanidine
benzo(a)pyrene
other: 2-Aminoanthracene
Details on test system and experimental conditions:
Concentration of the test substance resulting in precipitation: 5000 µg/plate
METHOD OF APPLICATION: in medium; in agar (plate incorporation);

DURATION
- Preincubation period:N/a
- Exposure duration: 48h
- Expression time (cells in growth medium):N/a
- Selection time (if incubation with a selection agent): N/a
- Fixation time (start of exposure up to fixation or harvest of cells): N/a

NUMBER OF REPLICATIONS: 3 plates at each cocentration against each tester strain


DETERMINATION OF CYTOTOXICITY
- Method: the frequency of revertant colonies assessed using a Domino colony counter.

OTHER EXAMINATIONS:
- Determination of polyploidy:
- Determination of endoreplication:
- Other:

OTHER:
Evaluation criteria:
All tester strain cultures exhibit a characteristic number of spontaneous revertants per plate in the vehicle and untreated controls. Acceptable ranges
are presented in the standard test method of this report with historical control ranges up to and including 1997 and 1998 presented in an Appendix to this report.
The appropriate characteristics for each tester strain have been confirmed, eg rfa cell-wall mutation and pkM101 plasmid R-factor etc.
All tester strain cultures were in the range of 1 to 9.9 x 10-9 bacteria per ml.
Each mean positive control value was at least two times 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. The historical control ranges up to and including 1997 and 1998 are presented in an Appendix to this report.
Statistics:
(Dunnett's method of linear regression(5)

Results and discussion

Test results
Key result
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
Vehicle controls validity:
valid
Positive controls validity:
valid
Additional information on results:
Observations:
Solvent control plates gave counts of revertant colonies
within the normal range.

All positive control chemicals gave increases in revertants,
either with or without the metabolising system as
appropriate, within expected ranges. No statistically
significant increase in the number of revertant colonies was
recorded for any of the bacterial strains with any dose of
the substance, either with or without metabolic activation.
The substance was found to be non-mutagenic under the
conditions of the test.
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 with metabolic activation
negative without metabolic activation

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

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