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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:
migrated information: read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
key study
Study period:
From 15 October, 2001 to 05 March, 2002
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Study was conducted according to the OECD guideline 476, EU method B.17 as well as in compliance with GLP.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2002
Report Date:
2002

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
OECD Guideline 476 (In Vitro Mammalian Cell Gene Mutation Test)
Deviations:
no
Qualifier:
according to
Guideline:
EU Method B.17 (Mutagenicity - In Vitro Mammalian Cell Gene Mutation Test)
Deviations:
no
Qualifier:
according to
Guideline:
other: Commission directive 2002/32/EC and U.K Envoirmrntal Mutagen Society
GLP compliance:
yes (incl. certificate)
Type of assay:
mammalian cell gene mutation assay

Test material

Reference
Name:
Unnamed
Type:
Constituent
Type:
Constituent
Test material form:
other: Pale straw colour liquid
Details on test material:
- Name of test material (as cited in study report): Arquad C-35 (purity 35%)
- Description: Pale straw colour liquid
- Batch number: RH020010082
- Storage conditions: Room temperature, in the dark

Method

Target gene:
Thymidine kinase gene
Species / strain
Species / strain:
mouse lymphoma L5178Y cells
Metabolic activation:
with and without
Metabolic activation system:
S9-mix
Test concentrations with justification for top dose:
For Experiment 1: 0.625, 1.25, 2.5, 5, 10 and 20 µg/mL for both with and without S9-mix
For Experiment 2: 0.313, 0.625, 0.938, 1.25, 2.5 and 5 µg/mL (without S9 mix) and 2.5, 5, 10, 15, 20 and 30 µg/mL (with S9-mix)
Vehicle:
RPMI 1640 without serum
Controlsopen allclose all
Negative controls:
yes
Solvent controls:
yes
True negative controls:
not specified
Positive controls:
yes
Positive control substance:
ethylmethanesulphonate
Remarks:
in the absence of S9-mix
Negative controls:
yes
Solvent controls:
yes
True negative controls:
not specified
Positive controls:
yes
Positive control substance:
cyclophosphamide
Remarks:
in the presence of S9-mix
Details on test system and conditions:
After a preliminary toxicity test, 0.625, 1.25, 2.5, 5, 10 and 20 µg/L was selected for the first experiment. The entire experiment was repeated to confirm the results of the first experiment. 3 h exposure were used both with and without S9 mix while for the second experiment, the exposure time was increased to 24 h. For the second experiment, the dose range was 2.5 to 30 µg/L with S9 mix and 0.313 to 5 µg/L without S9 mix.
Evaluation criteria:
For a test substance to give a significant result then two or more of the following criteria should be met:
a) A greater than three-fold increase in the mutant frequency/survivor over the negative control value.
b) A dose-related increase in the mutant frequency per survivor.
c) An increase in the absolute number of mutants.

Results and discussion

Test results
Species / strain:
mouse lymphoma L5178Y cells
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity:
yes
Vehicle controls valid:
yes
Negative controls valid:
yes
Positive controls valid:
yes
Remarks on result:
other:
Remarks:
Migrated from field 'Test system'.
Additional information on results:
RANGE-FINDING/SCREENING STUDIES: Yes

Any other information on results incl. tables

There was evidence of toxicity with the test substance in both the presence and absence of S9-mix as indicated by relative suspension growth (RSG), this was confirmed by the decrease in relative total growth (RTG). There was no evidence of a reduction in Day 2 viability, therefore indicating that no residual toxicity occurred, in either the presence or absence of S9-mix. Optimum level of toxicity was achieved, in both the presence and absence of S9-mix. The toxicity observed at 30 µg/mL in the presence of metabolic activation exceeded the upper acceptable limit of 90%; therefore it was excluded from the statistical analysis.

Applicant's summary and conclusion

Conclusions:
Interpretation of results (migrated information):
negative with or without metabolic activation

Under the test conditions, the test substance did not show mutagenic activity in mouse lymphoma assay.
Executive summary:

An OECD 476 study was conducted to evaluate the potential of the read-across substance C12-18 TMAC (active ingredient 35%) to induce mutations at the TK (thymidine kinase) locus in L5178Y mouse lymphoma cells. After a preliminary toxicity test, 0.625, 1.25, 2.5, 5, 10 and 20 µg/L was selected for the first experiment. The experiment was repeated to confirm the results of the first experiment. Three hour exposures were used both with and without S9-mix while for the second experiment, the exposure time was increased to 24 hours. For the second experiment, the concentration range was 2.5 to 30 µg/L with S9-mix and 0.313 to 5 µg/L without S9-mix. The test substance did not induce a statistically significant or concentration-related increase in the mutant frequency at any concentration level, either with or without metabolic activation. Adequate levels of toxicity were achieved in all exposure groups. Under the test conditions, C12-18 TMAC did not show mutagenic activity in mouse lymphoma assay.