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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
Study period:
15 sept 1997 - 2 October 1997
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1997
Report Date:
1997

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)
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: viscous
Details on test material:
- Name of test material (as cited in study report): Zonarez A-25
- Substance type: Not reported
- Physical state: Yellow extremely viscous liquid
- Lot/batch No.: PC7150
- Stability under test conditions: Not reported
- Date received: 11 August 1997
- Storage condition of test material: Room temperature under nitrogen until 14 August, thereafter room temperature in the dark under nitrogen
Specific details on test material used for the study:
Test Material: Zonarez A-25
Batch: PC7150
Description: yellow extremely viscous liquid
Date received: 11 August 1997
Storage: Room temperature under nitrogen

Method

Target gene:
TA 100 TA 1535 TA 102 TA 1537 TA98
Species / strain
Species / strain / cell type:
S. typhimurium TA 1535, TA 1537, TA 98 and TA 100
Details on mammalian cell type (if applicable):
- Supplier: University of California at Berkely
- Date supplier: August 1995
- Storing condition: -196 °C in a Statebourne liquid nitrogen freezer
- Type and identity of media:
- Properly maintained: yes/no
- Periodically checked for Mycoplasma contamination: yes/no
- Periodically checked for karyotype stability: yes/no
- Periodically "cleansed" against high spontaneous background: yes/no
Metabolic activation:
with and without
Test concentrations with justification for top dose:
0, 50, 150, 500, 1500, 5000 µg/plate
Vehicle / solvent:
- Vehicle(s)/solvent(s) used: tetrahydrofuran
- Justification for choice of solvent/vehicle: Not reported
Controls
Negative solvent / vehicle controls:
yes
Remarks:
tetrahydrofuran
True negative controls:
yes
Remarks:
2-aminoanthracene, 1,8-dihydroxyantharaquinone
Positive controls:
yes
Positive control substance:
4-nitroquinoline-N-oxide
9-aminoacridine
N-ethyl-N-nitro-N-nitrosoguanidine
mitomycin C
Details on test system and experimental conditions:
METHOD OF APPLICATION: sterile plates of Vogel-Bonner Minimal agar

DURATION
- Preincubation period: Not reported
- Exposure duration: 48 hr
- Temperature: 37°C
- Expression time (cells in growth medium): Not reported

NUMBER OF REPLICATIONS: Frequency of revertant colonies was assessed using a Domino colony counter

DETERMINATION OF CYTOTOXICITY: Not reported
Evaluation criteria:
For a substance to be considered positive in this test system, it should have induced a dose-related and statistically significant increase in the relevant count in one or more strains of bacteria in the presence and/or absence of S9 in both experiments at sub-toxic dose levels. To be considered negative, the number of revertants at each dose level should be less than twofold that of the vehicle frequency.
Statistics:
All data was analysed using the statistical methods recommended by the UKEMS with Dunnett's method of linear regression used to calculate the result.

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
Untreated negative controls validity:
valid
Positive controls validity:
valid
Additional information on results:
No toxicity was exhibited to any of the strains of Salmonella used. A precipitate was observed at 5000 µg/plate. This did not prevent the scoring of revertant colonies.
Remarks on result:
other: strain/cell type: male Sprague-Dawley
Remarks:
Migrated from field 'Test system'.

Any other information on results incl. tables

Mean number of revertant colonies for the toxicity assay
  DOSE (µg/plate)
Strain 0 50 150 500 1500 5000
TA100 122 125 118 127 119 199P
P=precipitate

Applicant's summary and conclusion

Conclusions:
Interpretation of results (migrated information):
negative

The test material Zonarez A-25 was considered to be non-mutagenic under the condition of this test.
Executive summary:

A Reverse Mutation Assay "Ames Test" using Salmonella S. typhimurium was conducted to assess the mutagenicity of the test material Zonarez A-25. The test material was tested up to the maximum recommended dose of 5000 µg/plate.

Significant increases in the frequency of revertant colonies of bacteria were recorded at any dose level either with or without metabolic activation. All the positive control chemicals used in the test induced significantly the frequency of revertant colonies and activity of the S9 fraction was shown to be satisfactory.

Results showed no toxicity to any of the strains of Salmonella used up to 5000 µg/plate. A precipitate was observed at this dose level, but it did not prevent the scoring of relevant colonies.

The test item was non-mutagenic under the conditions of the test.