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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:
supporting study
Study period:
no data
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
study well documented, meets generally accepted scientific principles, acceptable for assessment
Remarks:
Only two S. typhimurium strains were used: TA 100 (basepair substitution) and TA98 (frameshift).

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1992
Report Date:
1992

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
OECD Guideline 471 (Bacterial Reverse Mutation Assay)
Deviations:
yes
Remarks:
only two bacteria strains were tested
Qualifier:
according to
Guideline:
EU Method B.13/14 (Mutagenicity - Reverse Mutation Test Using Bacteria)
Deviations:
yes
Remarks:
only two bacteria strains were tested
GLP compliance:
yes
Type of assay:
bacterial reverse mutation assay

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
solid: particulate/powder
Details on test material:
- Name of test material (as cited in study report): Sicocer F Eisenrosa 2320
- Physical state: solid, pink powder
Specific details on test material used for the study:
STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: at room temperature

Method

Species / strainopen allclose all
Species / strain / cell type:
S. typhimurium TA 98
Additional strain / cell type characteristics:
other: rfa; uvrB; ampicillin resistence (R factor plamid pKM 101); and a modified postreplication DNA repair system, which increases the mutation rate by inducing a defective repair in the DNA
Species / strain / cell type:
S. typhimurium TA 100
Additional strain / cell type characteristics:
other: rfa; uvrB; ampicillin resistence (R factor plamid pKM 101); and a modified postreplication DNA repair system, which increases the mutation rate by inducing a defective repair in the DNA
Metabolic activation:
with and without
Metabolic activation system:
S9-mix
Test concentrations with justification for top dose:
standard plate test: 0, 20, 100, 500, 2500 and 5000 µg/plate
preincubation test: 0, 20, 100, 500, 2500 and 5000 µg/plate
Vehicle / solvent:
- Vehicle(s)/solvent(s) used: DMSO
Controlsopen allclose all
Untreated negative controls:
no
Negative solvent / vehicle controls:
yes
Remarks:
Parallel with each experiment with and without S9-mix a solvent control is carried out.
True negative controls:
no
Positive controls:
yes
Positive control substance:
other: 2-aminoanthracene (2.5 µg/plate), dissolved in DMSO
Remarks:
with metabolic activation; strains TA 98 and TA 100
Untreated negative controls:
no
Negative solvent / vehicle controls:
yes
Remarks:
Parallel with each experiment with and without S9-mix a solvent control is carried out.
True negative controls:
no
Positive controls:
yes
Positive control substance:
other: N-methyl-N'-nitro-N-nitroso-guanidine (5 µg/plate), dissolved in DMSO
Remarks:
without metabilic activation; strain TA 100
Untreated negative controls:
no
Negative solvent / vehicle controls:
yes
Remarks:
Parallel with each experiment with and without S9-mix a solvent control is carried out.
True negative controls:
no
Positive controls:
yes
Positive control substance:
other: 4-nitro-o-phenylendiamine (10 µg/plate), dissolved in DMSO
Remarks:
without metabolic activation; strain TA 98
Details on test system and experimental conditions:
METHOD OF APPLICATION: in agar (plate incorporation) and preincubation

DURATION
- Preincubation period: 20 minutes at 37°C (preincubation test only)
- Exposure duration: 48 hours at 37°C in the dark

NUMBER OF REPLICATIONS: 3

EVALUATION
- The frequency of revertant colonies was assessed by counting.

DETERMINATION OF CYTOTOXICITY
- Method: Examination of the background growth.

Titer determination:
- The titer is determined only in the experiments with S9-mix both without test substance (solvent only) and after adding the two highest amounts of substance. The effects of a 10E-6 dilution of the bacteria suspensions on the growth of the bacteria were examined. The frequency of revertant colonies was assessed by counting.
Evaluation criteria:
A substance to be characterised as positive in the Ames test has to fulfill the following requirements:
- doubling of the spontaneous mutation rate (control)
- dose response relationship
- reproducibility of the results
Statistics:
not mandatory for this test system

Results and discussion

Test resultsopen allclose all
Species / strain:
S. typhimurium TA 98
Metabolic activation:
with and without
Genotoxicity:
negative
Remarks:
In the standard plate test and in the preincubation test, no toxicological significant increases in the frequency of revertant colonies were recorded for any of the bacterial strains, with any dose of the test material.
Cytotoxicity / choice of top concentrations:
no cytotoxicity nor precipitates, but tested up to recommended limit concentrations
Remarks:
The test material was non-toxic under the conditions tested.
Vehicle controls validity:
valid
Untreated negative controls validity:
not examined
Positive controls validity:
valid
Species / strain:
S. typhimurium TA 100
Metabolic activation:
with and without
Genotoxicity:
negative
Remarks:
In the standard plate test and in the preincubation test, no toxicological significant increases in the frequency of revertant colonies were recorded for any of the bacterial strains, with any dose of the test material.
Cytotoxicity / choice of top concentrations:
no cytotoxicity nor precipitates, but tested up to recommended limit concentrations
Remarks:
The test material was non-toxic under the conditions tested.
Vehicle controls validity:
valid
Untreated negative controls validity:
not valid
Positive controls validity:
valid
Additional information on results:
TEST-SPECIFIC CONFOUNDING FACTORS
- Precipitation: No precipitation of the test substance was observed.

ADDITIONAL INFORMATION ON CYTOTOXICITY:
- No bacteriotoxic effect (reduced his- background growth) was observed.

Applicant's summary and conclusion

Conclusions:
The test substance Sicocer F Eisenrosa 2320 was considered to be non-mutagenic under the conditions of the test.