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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:
9 June to 3 July 1978
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
comparable to guideline study with acceptable restrictions
Remarks:
Non-GLP study, evaluation criteria, historical control data not reported

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1978

Materials and methods

Test guideline
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 471 (Bacterial Reverse Mutation Assay)
Deviations:
yes
Remarks:
evaluation criteria, historical control data not reported
Principles of method if other than guideline:
Not applicable
GLP compliance:
not specified
Remarks:
pre-GLP but considered to be equivalent to GLP standard
Type of assay:
bacterial reverse mutation assay

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
solid
Remarks:
Powder
Details on test material:
- Description: Beige coloured powder
- Storage condition of test material: Stored in the drak, under nitrogen and in a dessicator at ambient room temperature (ca 18°C)..

Method

Target gene:
Histidine and tryptophan gene for Salmonella typhimurium and Escherichia coli, respectively.
Species / strainopen allclose all
Species / strain / cell type:
S. typhimurium, other: TA 1535, TA 1537, TA 1538, TA 98 and TA 100
Details on mammalian cell type (if applicable):
Not applicable
Additional strain / cell type characteristics:
not applicable
Species / strain / cell type:
E. coli WP2 uvr A
Details on mammalian cell type (if applicable):
Not applicable
Additional strain / cell type characteristics:
not applicable
Metabolic activation:
with and without
Metabolic activation system:
10 % S9 mix; S9 from liver of SD rats induced with Aroclor 1254
Test concentrations with justification for top dose:
- Test: 10, 33.3, 100.0, 333.3, 1000 and 3300 µg/plate in S. typhimurium strains TA 1535, TA 1537, TA 1538, TA 98, TA 100 and in E.coli WP2 uvrA-, with and without S9-mix
- Retest (at higher dose levels): 1000, 2000, 4000, 6000 and 8000 µg/plate in S. typhimurium strains TA 1535, TA 1537, TA 1538, TA 98 and TA 100, with and without S9-mix
- Test to deduce if exposure to air, light and humidity affect the mutagenic activity of test item: 100, 500, 1000, 2000, 4000 and 6000 µg/plate in S. typhimurium strain TA 100, with and without S9-mix
Vehicle / solvent:
- Vehicle(s)/solvent(s) used: The test compound was dissolved and diluted in Dimethylsulphoxide (DMSO)
Controls
Untreated negative controls:
no
Negative solvent / vehicle controls:
yes
Remarks:
DMSO
True negative controls:
no
Positive controls:
yes
Positive control substance:
other: 2-Aminoanthracene
Remarks:
with and without S9-mix
Details on test system and experimental conditions:
METHOD OF APPLICATION: in agar (plate incorporation)

DURATION
- Exposure duration: Two days at 37 °C

NUMBER OF REPLICATIONS: 3 plates/dose

DETERMINATION OF CYTOTOXICITY
- Method: Evaluation of the toxicity was performed on the basis of microcolony growth.

OTHERS:
- After two days incubation at 37 °C the colonies counted using a New Brunswick Inc. (New Brunswick, N.J.) Biotran II automated counter set for maximum sensitivity (colonies of 0.1 mm or more in diameter counted). The plates were also examined for precipitates and, microscopically, for microcolony growth.
Evaluation criteria:
No data
Statistics:
No data

Results and discussion

Test resultsopen allclose all
Key result
Species / strain:
S. typhimurium, other: TA 1535, TA 1537, TA 1538, 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
Key result
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
Additional information on results:
Cytotoxicity: no cytotoxicity.

Results of mutagenicity:
The substance was mutagenic in strain TA 100 both with activation at a lowest effective dose of 3300 µg/plate and without activation at a lowest effective dose of 1000 µg/plate. The compound was not mutagenic in E. coli WP2 uvrA. Exposure to air, light and humidity did not affect its mutagenic activity in strain TA 100

Any other information on results incl. tables

None

Applicant's summary and conclusion

Conclusions:
Under the test condition, the test item is mutagenic in S. typhimurium TA 100 with and without metabolic activation.
Executive summary:

In a reverse gene mutation assay, strains of Salmonella typhimurium (TA 1535, TA 1537, TA 1538, TA 98 and TA 100) and Escherichia coliWP2 uvrA- were exposed to the test item at 10, 33.3, 100.0, 333.3, 1000 and 3300 µg/plate. The compound was also tested at 1000, 2000, 4000, 6000 and 8000 µg/plate to obtain a mutagenic dose response and at 100, 500, 1000, 2000, 4000 and 6000 µg/plate to assess the effect of air, light and humidity.

 

The substance was mutagenic in S. typhimurium TA 100 at a lowest effective dose of 1000 µg/plate in the absence of the activation system and 3300 µg/plate in the presence of the activation system. Even though the compound was known to decompose in the presence of air and humidity, exposure of the compound to these effects did not alter its mutagenic activity. The compound was not mutagenic in E. coli WP2 uVrA-.

 

The vehicle control plates gave counts of revertant colonies within the normal range. Positive control induced marked increases in the frequency of revertant colonies indicating the validity of the study. 

 

Under the test condition, the test item is mutagenic in S. typhimurium TA 100 with and without metabolic activation.