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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:
2007-12-14
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2008
Report Date:
2008

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 471 (Bacterial Reverse Mutation Assay)
GLP compliance:
yes
Type of assay:
bacterial reverse mutation assay

Test material

Reference
Name:
Unnamed

Method

Species / strainopen allclose all
Species / strain / cell type:
E. coli WP2 uvr A
Species / strain / cell type:
S. typhimurium TA 1535, TA 1537, TA 98 and TA 100
Metabolic activation:
with and without
Metabolic activation system:
Rat liver S9-mix induced by a combination of phenobarbital and 5,6-benzoflavone
Test concentrations with justification for top dose:
Dose range finding test 1:
- 4.88, 19.5, 78.1, 313, 1250, and 5000 µg/plate
Dose range finding test 2:
- 2.44, 4.88, 9.77, 19.5, 39.1, and 78.1 µg/plate without S9
- 9.77, 19.5, 39.1, 78.1, 156, and 313 µg/plate with S9
Main test
- 2.44, 4.88, 9.77, 19.5, 39.1, and 78.1 µg/plate without S9
- 9.77, 19.5, 39.1, 78.1, 156, and 313 µg/plate with S9
Vehicle / solvent:
- Solvent used: DMSO
- Justification for choice of solvent: the test substance was found to be soluble in DMSO up to 50 mg/mL
Controls
Untreated negative controls:
yes
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
other: see section "Any other information on materials and methods incl. tables"
Details on test system and experimental conditions:
METHOD OF APPLICATION: preincubation method

DURATION
- Preincubation period: 20 minutes
- Exposure duration: 48 hours

NUMBER OF REPLICATIONS:
- Doses of the test substance were tested in duplicate.

DETERMINATION OF CYTOTOXICITY
- Method: on the basis of a decline in the number of spontaneous revertants.
Evaluation criteria:
The test substance was judged to be positive when the number of revertant colonies increased to twice or more that in the negative control in a concentration-dependent manner and also the reproducibility of the test results was obtained. In all other cases, it was judged to be negative.

Results and discussion

Test resultsopen allclose all
Species / strain:
E. coli WP2 uvr A
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
cytotoxicity
Vehicle controls validity:
valid
Untreated negative controls validity:
not applicable
Positive controls validity:
valid
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:
cytotoxicity
Vehicle controls validity:
valid
Untreated negative controls validity:
not applicable
Positive controls validity:
valid
Additional information on results:
RANGE-FINDING/SCREENING STUDIES:
- Dose range finding test 1: The number of revertant colonies in the test substance treatment groups was less than twice that in the solvent control in the groups of treatment with and without S9 mix. The bacterial growth inhibition was observed at 78.1 µg/plate or more in all test strains without S9 mix and at 313 µg/plate or more in all test strains with S9 mix. The precipitation of the test substance was not observed at any doses in the groups of treatment with and without S9 mix.
- Dose range finding test 2: The number of revertant colonies in the test substance treatment groups was less than twice that in the solvent control groups of treatment with and without S9 mix. The bacterial growth inhibition was observed at 39.1 µg/plate or more in TA100, TA1535, TA98, and TA1537 and at 78.1 µg/plate in WP2uvrA in the groups of treatment without S9 mix and at 156 µg/plate or more in TA100, TA1535, TA98, and TA1537 and at 313 µg/plate in WP2uvrA in the groups of treatment with S9 mix. The precipitation of the test substance was not observed at any doses in the groups of treatment with and without S9 mix.

MAIN STUDY:
The number of revertant colonies in the test substance treatment groups was less than twice that in the solvent control groups of treatment with and without S9 mix. The bacterial growth inhibition was observed at 39.1 µg/plate or more in TA100, TA1535, TA98, and TA1537 and at 78.1 µg/plate in WP2uvrA in the groups of treatment without S9 mix and at 156 µg/plate or more in TA100, TA1535, TA98, and TA1537 and at 313 µg/plate in WP2uvrA in the groups of treatment with S9 mix. The precipitation of the test substance was not observed at any doses in the groups of treatment with and without S9 mix.
Remarks on result:
other: all strains/cell types tested
Remarks:
Migrated from field 'Test system'.

Applicant's summary and conclusion

Conclusions:
The substance is not mutagenic in the Salmonella typhimurium reverse mutation assay performed according to OECD 471.
Executive summary:

The mutagenic activity of the substance was evaluated in accordance with OECD 471 and according to GLP principles. A preincubation assay was performed with S. typhimurium strains TA100, TA1535, TA98, TA1537, and E. coli WP2uvrA with and without metabolic activation (Rat liver S9-mix induced by a combination of phenobarbital and 5,6-benzoflavone). Adequate solvent (DMSO) and positive controls were included. Two dose range finding tests were performed and one main test. In the main test all stains were dosed with 2.44, 4.88, 9.77, 19.5, 39.1, and 78.1 µg/plate without metabolic activation and 9.77, 19.5, 39.1, 78.1, 156, and 313 µg/plate with metabolic activation. The experiment was performed in duplicate. The number of revertant colonies in the test substance treatment groups was less than twice that in the solvent control groups of treatment with and without S9 mix. Under the conditions of the test the substance is not mutagenic.