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Toxicological information

Genetic toxicity: in vitro

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Administrative data

Endpoint:
in vitro gene mutation study in mammalian cells
Remarks:
Type of genotoxicity: gene mutation
Type of information:
experimental study
Adequacy of study:
key study
Study period:
July - Oct 1982
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Scientifically acceptable; study conform to OECD Guideline 476 with minor deviation; GLP study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1982
Report Date:
1982

Materials and methods

Test guideline
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 476 (In Vitro Mammalian Cell Gene Mutation Test)
Deviations:
no
GLP compliance:
yes
Type of assay:
mammalian cell gene mutation assay

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
no data

Method

Target gene:
Thymidine Kinase Lokus of L5178Y TK+/- mouse lymphoma cells
Species / strain
Species / strain / cell type:
mouse lymphoma L5178Y cells
Metabolic activation:
with and without
Metabolic activation system:
S9 Homogenate
Test concentrations with justification for top dose:
600, 800, and 1000 µg/ml two cultures (tested in triplicate each)
75, 150, 300, 600, 800 and 1000 µg/ml two cultures (tested in triplicate each)
Vehicle / solvent:
- Vehicle(s)/solvent(s) used: ethanol
Controlsopen allclose all
Untreated negative controls:
yes
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
ethylmethanesulphonate
Remarks:
without metabolic activation
Untreated negative controls:
yes
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
N-dimethylnitrosamine
Remarks:
with metabolic activation
Details on test system and experimental conditions:
The test material appeared soluble in the assay medium up to about 300 µg/ml. The test was performed up to the dose level of 1000 µg/ml
Evaluation criteria:
Assay Acceptance Criteria:
1. The average absolute cloning effiency of the negative controls should be between 70 and 130%.
All assays below 50% cloning efficiency are unacceptable.
2. The solvent and untreated controls normally have the same growth rates and cloning efficiencies within experimental error. An assys will be unacceptable if the average percent relative growth of the solvent controls is less than about 70% of the untreated control value.
3. The minimum acceptable value for the suspension growth of the average negtive control (average of the solvent and untreated control value) for two days is 8.0.
4. The background mutant frequency is calculated separately for concurrent activation and nonactivation. For both conditions, the normal range of background frequencies for assays performed with differen cell stocks is 5 x 10(exp)-6 to 60 x 10(exp)-6. Assays with backgrounds outside this range are not necessarily invalid but will not be used as primary evidence for the evaluation of a test material.
5. An assay will be acceptable in the absence of a positive control only if the test material clearly shows mutagenic activity. If the test material appaers to have no or only weak mutagenic activity, an acceptablee assay must have a positive control mutant frequency above the lower limits of the normal range.
6. For test materials with little or no mutagenic activity, an assay must include applied concentrations that reduce the suspension growth to 10 to 15% of the average solvent control or reach the maximum applied concnetrations given in the corresponding guideline.
7. An experimental treatment that results in fewer than 2.5 x 10(exp)6 cells by the end of the two-day growth period will not be cloned for mutant analysis.
8. An experimental mutant frequency will be considered accpetable for evaluation only if the relative cloning efficiency is 10% or greater and the total number of viable clones exceeds about 20.
Statistics:
None

Results and discussion

Test results
Species / strain:
mouse lymphoma L5178Y cells
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
no cytotoxicity, but tested up to precipitating concentrations
Vehicle controls validity:
valid
Untreated negative controls validity:
valid
Positive controls validity:
valid
Additional information on results:
ADDITIONAL INFORMATION ON CYTOTOXICITY: No significant toxic effect observed up to the highest dose level which was well above the solubility limit of the test susbtance in the test medium
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 and without metabolic activation

The test substance Hostanox SE 10 is not mutagenic in Mouse Lymphoma Assay.
Executive summary:

The test substance was tested for mutagenicity using mammalian cells L5178Y TK+/- with and without metabolic activation in the dose range of 75-1000 µg/ml. The highest dose level was well above the solubility limit of the test substance in the test medium and obvious cell toxicity was not observed. No mutagenic activity was found.