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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
Study period:
2004-08-24 to 2004-11-15
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: GLP compliant; Guideline Study (OECD 471)

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2004
Report Date:
2004

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
EU Method B.13/14 (Mutagenicity - Reverse Mutation Test Using Bacteria)
Version / remarks:
of May 19, 2000
Deviations:
no
Qualifier:
according to
Guideline:
OECD Guideline 471 (Bacterial Reverse Mutation Assay)
Version / remarks:
adopted July 21, 1997
Deviations:
no
Qualifier:
according to
Guideline:
JAPAN: Guidelines for Screening Mutagenicity Testing Of Chemicals
Deviations:
no
GLP compliance:
yes (incl. certificate)
Type of assay:
bacterial reverse mutation assay

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Aggregate State at Room Temperature: solid;
- Colour: red;
- Storage: room temperature;

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:
Phenobarbital/p-Naphthoflavone induced rat liver S9
Test concentrations with justification for top dose:
Experiment I: 3; 10; 33; 100; 333; 1000; 2500; and 5000 µg/plate;
Experiment II: 33; 100; 333; 1000; 2500; and 5000 µg/plate;
Vehicle / solvent:
DMSO
Controlsopen allclose all
Untreated negative controls:
yes
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
other: sodium azide (S. typh. TA1535, TA100); 4-nitro-o-phenylene diamine (S. typh. TA1537, TA98; methyl methanesulphonate (E. coli WP2 uvrA);
Remarks:
without metabolic activation
Untreated negative controls:
yes
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
other: 2-aminoanthracene (S. typh. TA1535, TA1537, TA98, TA100, E. coli WP2uvrA);
Remarks:
with metabolic activation
Details on test system and experimental conditions:
METHOD OF APPLICATION: plate incorporation (experiment I) and preincubation (experiment II)

DURATION
- Preincubation period: 60 min
- Exposure duration: 48 hours

NUMBER OF REPLICATIONS: three replicates per dose and per strain

DETERMINATION OF CYTOTOXICITY
Toxicity of the test item results in a reduction in the number of spontaneous revertants or a clearing of the bacterial background lawn.
Evaluation criteria:
A test item is considered as a mutagen if a biologically relevant increase in the number of revertants exceeding the threshold of twice (strains TA 98, TA 100, and WP2 uvrA) or thrice (strains TA 1535 and TA 1537) the colony count of the corresponding solvent control is observed.

A dose dependent increase is considered biologically relevant if the threshold is exceeded at more than one concentration.

An increase exceeding the threshold at only one concentration is judged as biologically relevant if reproduced in an independent second experiment.
A dose dependent increase in the number of revertant colonies below the threshold is regarded as an indication of a mutagenic potential if reproduced in an independent second experiment. However, whenever the colony counts remain within the historical range of negative and solvent controls such an increase is not considered biologically relevant.
Statistics:
No statistical evaluation of the data is required.

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
Remarks:
in TA 1535 and TA 1537 (-S9) and in strain TA 100 (+/- S9)
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 nor precipitates, but tested up to recommended limit concentrations
Vehicle controls validity:
valid
Untreated negative controls validity:
valid
Positive controls validity:
valid
Additional information on results:
TEST-SPECIFIC CONFOUNDING FACTORS
- Precipitation: Occurred in experiment I at concentrations of 333 µg/plate and higher and in experiment II at concentrations of 1000 µg/plate and higher in all test strains with and without S9.

COMPARISON WITH HISTORICAL CONTROL DATA:

ADDITIONAL INFORMATION ON CYTOTOXICITY:
Minor toxic effects, evident as a reduction in the number of revertants, occurred in experiment I in strains TA 1535 and TA 1537 at 2500 µg/plate with metabolic activation and in strain TA 100 at 5000 µg/plate with and without metabolic activation.
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