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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:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Equivalent to OECD 471. GLP study.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1987

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
other: Ames, B.N., McCann, J. and Yamasaki, E. (1975) and Venitt, S. and Crofton-Sleigh, C. (1981)
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 471 (Bacterial Reverse Mutation Assay)
Deviations:
yes
Remarks:
(triplicate plating should be used instead of duplicates. However, this deviation does not affect the outcome of the study)
GLP compliance:
yes
Type of assay:
bacterial reverse mutation assay

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Physical state: Pale yellow powder.
- Analytical purity: 99.04%
- Lot/batch No.: 5/87; Indent 9200/9622
- Storage condition of test material: Following its arrival in Compound Control this test substance was stored in the dark at ambient temperature.
- Stability: Infra-red spectra of the test substance were taken. There were no significant differences between the spectra and so, on this basis, the test substance was judged to have been stable for the duration of this study.
- Stability of formulations on the test substance: The stabilities of formulations of the test substance in acetone were assessed. These formulations were stable for at least 7.5 hours.

Method

Species / strainopen allclose all
Species / strain / cell type:
S. typhimurium TA 1535, TA 1537, TA 98 and TA 100
Species / strain / cell type:
S. typhimurium TA 1538
Species / strain / cell type:
E. coli WP2 uvr A pKM 101
Metabolic activation:
with and without
Metabolic activation system:
rat liver S9 fraction
Test concentrations with justification for top dose:
31.25, 62.5, 125, 250, 500, 1000, 2000 or 4000 µg per plate
Vehicle / solvent:
- Vehicle(s)/solvent(s) used: acetone
Controlsopen allclose all
Negative solvent / vehicle controls:
yes
Positive controls:
yes
Positive control substance:
sodium azide
Remarks:
S. typhimurium TA1535 (with and without metabolic activation)
Negative solvent / vehicle controls:
yes
Positive controls:
yes
Positive control substance:
benzo(a)pyrene
Remarks:
S. typhimurium TA1538, TA98 and TA100 (with and without metabolic activation)
Negative solvent / vehicle controls:
yes
Positive controls:
yes
Positive control substance:
other: potassium dichromate
Remarks:
E. coli WP2 uvrA pKM 101 (with and without metabolic activation)
Negative solvent / vehicle controls:
yes
Positive controls:
yes
Positive control substance:
other: neutral red
Remarks:
S. typhimurium TA1537
Details on test system and experimental conditions:
METHOD OF APPLICATION: 20 µl volumes of solutions of the test substance in acetone were added to top agar mix to give final concentrations.

DURATION
- Exposure duration: The cultures were incubated at 37 ªc for 48-72 hours before the revertant colonies were counted.


NUMBER OF REPLICATIONS: Two replicates


Evaluation criteria:
Reproducible dose-related increases or values of 2.5 x control values or greater are considered to indicate a mutagenic response.

Results and discussion

Test results
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
no cytotoxicity
Vehicle controls validity:
valid
Positive controls validity:
valid
Additional information on results:
The test compound formed a flakey precipitate at amounts of 500 µg per plate and above in the top agar showing that it was not totally miscible at these amounts.

The addition of 2000 µg per ml test substance (equivalent to 4000 µg per plate) caused the pH of the medium to change from 7.49 to 7.45.

Microscopical evaluation of the background lawn showed no evidence of cytotoxicity at amounts up to 4000 µg per plate either in the presence or in the absence of rat liver S9 fraction.
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

It was concluded that the test substance did not induce reverse gene mutation in the selected bacterial tester strains under the experimental conditions described.
Executive summary:

The mutagenic activity of the test substance was investigated in agar layer cultures of selected bacterial tester strains of Salmonella typhimurium and Escherichia coli. Assays were performed both in the presence and in the absence of and S9 microsomal fraction obtained from a liver homogenate from rats pre-treated with Aroclor 1254. It was concluded that the test substance did not induce reverse gene mutation in the selected bacterial tester strains under the experimental conditions described.