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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:
21 Oct - 12 Nov 1980
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Comparable to guideline study, well documented

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1981
Report date:
1981

Materials and methods

Test guideline
Qualifier:
equivalent or similar to guideline
Guideline:
OECD Guideline 471 (Bacterial Reverse Mutation Assay)
Deviations:
yes
Remarks:
for some strains positive controls were only included in assays with S9, for other strains positive controls were only included in assays without S9 mix.
Principles of method if other than guideline:
No reference to the overall method used is given in the study report. However, the method used is well described and references for certain work steps are stated. In principal the method used is similar to OECD 471.
GLP compliance:
no
Remarks:
study performed prior to implementation of GLP
Type of assay:
bacterial reverse mutation assay

Test material

Reference
Name:
Unnamed
Type:
Constituent

Method

Target gene:
his operon (S. typhimurium strains)
tryptophan operon (E. coli strain)
Species / strainopen allclose all
Species / strain / cell type:
other: S. typhimurium TA 1535, TA 100, TA 1537, TA 1538, TA 98
Species / strain / cell type:
E. coli WP2 uvr A pKM 101
Metabolic activation:
with and without
Metabolic activation system:
cofactor supplemented post-mitochondrial fraction (S9 mix) prepared from the liver of male rats treated with Aroclor 1254 (500 mg/kg bw)
Test concentrations with justification for top dose:
378, 1130, 3780, 11300, 37800 and 113300 µg TMT15/plate (equivalent to 56.7, 169.5, 567, 1695, 5670, 16995 µg anhydrous TMT/plate)
Vehicle / solvent:
- Vehicle/solvent used: distilled water
Controls
Untreated negative controls:
no
Negative solvent / vehicle controls:
yes
Remarks:
distilled water
True negative controls:
no
Positive controls:
yes
Positive control substance:
other: +S9: pyrene (400µg/plate in DMSO, TA1537); 4-acetylaminofluorene (1mg/plate in DMSO, TA1538, TA98); -S9: sodium azide (1µg/plate in water, TA1535); methyl methanesulphonate (100µg/plate in DMSO, TA100, E.coli); 9-aminoacridine (50 µg/plate in DMSO,TA1537)
Details on test system and experimental conditions:
METHOD OF APPLICATION: 1st and 2nd main experiment: plate incorporation method

DURATION
- Exposure duration: 48 hours (37°C)

NUMBER OF REPLICATIONS: triplicates in two independent experiments

DETERMINATION OF CYTOTOXICITY: reduction in the total number of bacteria added to the plate (i.e. thin background lawn)
Evaluation criteria:
The test substance may be considered positive , if the following criteria are met:
S. typhimurium TA 1535, TA 1537, TA 1538, TA 98 and E. coli at least a doubling of the mean control values
S. typhimurium TA 100 at least a 1.5-fold increase over control value
In addition, dose-related responses were considered.
Statistics:
Mean values were calculated.

Results and discussion

Test resultsopen allclose all
Species / strain:
other: S. typhimurium TA 1535, TA 100, TA 1537, TA 1538, TA 98
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
cytotoxicity
Remarks:
slightly toxic at highest dose level
Vehicle controls validity:
valid
Untreated negative controls validity:
not examined
Positive controls validity:
valid
Species / strain:
E. coli WP2 uvr A pKM 101
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
cytotoxicity
Remarks:
slightly toxic at highest dose level
Vehicle controls validity:
valid
Untreated negative controls validity:
not examined
Positive controls validity:
valid
Additional information on results:
RANGE-FINDING/SCREENING STUDIES:
The dose levels were selected on the basis of observations from a preliminary toxicity study in strain TA 100. Concentrations of 0.378, 1.13, 3.78, 11.3, 37.8 and 113.3 mg/plate were not toxic in strain TA 100 as defined by an observed reduction in the total number of bacteria (i.e. thin background lawn) .
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 metabolic activation
negative without metabolic activation

Under the conditions of this study, the substance was not mutagenic in any of the 6 strains tested.