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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
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: OECD guideline study, GLP

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2003
Report Date:
2003

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 471 (Bacterial Reverse Mutation Assay)
Version / remarks:
adopted July 21, 1997
Deviations:
no
GLP compliance:
yes (incl. certificate)
Type of assay:
bacterial reverse mutation assay

Test material

Reference
Name:
Unnamed
Type:
Constituent

Method

Species / strainopen allclose all
Species / strain / cell type:
S. typhimurium TA 1535, TA 1537, TA 98 and TA 100
Species / strain / cell type:
E. coli WP2 uvr A
Metabolic activation:
with and without
Metabolic activation system:
S9 mix from phenobarbital and ß-naphthoflavone induced liver of male Wistar rats.
Test concentrations with justification for top dose:
Experiment I: 0; 33; 100; 333; 1000; 2500; and 5000 µg/plate
Experiment II: 0; 33; 100; 333; 1000; 2500; and 5000 µg/plate
Vehicle / solvent:
- Solvent used: dimethylsulfoxide
Controls
Untreated negative controls:
yes
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
other: Without S9-mix: Sodium azide (TA 1535, TA 100); 4-nitro-o-phenylene-diamine (TA 1537, TA 98); methyl methane sulfonate (WP2 uvrA); With S9-mix: 2-aminoanthracene (TA 1535, TA 1537, TA 98, TA 100, WP2 uvrA)
Details on test system and experimental conditions:
METHOD OF APPLICATION:
Experiment 1: in agar (plate incorporation)
Experiment 2: preincubation

DURATION
- Exposure duration: 48 hrs

NUMBER OF INDEPENDENT EXPERIMENTS: 2
NUMBER OF REPLICATIONS: 3

DETERMINATION OF CYTOTOXICITY
- Method: colony counting
Evaluation criteria:
Reaction to a substance is regarded as positive if all of the following criteria are met
- doubling of spontaneous control mutation rate
- dose-response relationship
- reproducibility of results
Statistics:
Not performed.

Results and discussion

Test resultsopen allclose all
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:
valid
Positive controls validity:
valid
Species / strain:
E. coli WP2 uvr A
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:
TEST-SPECIFIC CONFOUNDING FACTORS
- Effects of pH: no
- Effects of osmolality: no
- Evaporation from medium: no
- Precipitation: The test item precipitated in the overlay agar at concentrations of 5000 µg/plate (TA98; without S9-mix), at 333 -5000 µg/plate (TA 100; with and without S9-mix), 333 -5000 µg/plate (WP2 UVrA; without S9-mix) and at 2500 - 5000 µg/plate (WP2 UVrA; with and without S9-mix).

COMPARISON WITH HISTORICAL CONTROL DATA:
The historical range of positive controls was exceeded in strains TA 1535 and TA 100 in both independent experiments without metabolic activation system. This effect indicates the sensitivity of the strains rather than comprising the assay.

ADDITIONAL INFORMATION ON CYTOTOXICITY:
No toxic effects, evident as a reduction in the number of revertants, occurred in the test groups with and without metabolic activation in experiment I. In experiment II, toxic effects were observed at higher concentrations with and without metabolic activation in nearly all S. typhimuriumstrains used.
Remarks on result:
other: all strains/cell types tested
Remarks:
Migrated from field 'Test system'.

Applicant's summary and conclusion