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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:
migrated information: read-across based on grouping of substances (category approach)
Adequacy of study:
key study
Study period:
From 22 AUG 1995 to 31 AUG 1995
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: see 'Remark'
Remarks:
As compared to OECD guideline 471 the study design has some methodological deviations (pre-incubation assay only with but not without metabolic activation (Prival modification for azo-dyes); investigations without metabolic activation were only tested in the plate incorporation assay; not all strains tested). But considering the characteristics of the test item the study design used completely covers the most sensitive parameters relevant for azo-dyes.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1995
Report Date:
1995

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
OECD Guideline 471 (Bacterial Reverse Mutation Assay)
Deviations:
yes
Remarks:
not tested in E. coli WP2uvr A or TA 102
Qualifier:
according to
Guideline:
other: EEC directive 92/69, L 383 A, Annex B14
Deviations:
not specified
Qualifier:
according to
Guideline:
EPA OTS 798.5265 (The Salmonella typhimurium Bacterial Reverse Mutation Test)
Deviations:
not specified
GLP compliance:
yes
Type of assay:
bacterial reverse mutation assay

Test material

Reference
Name:
Unnamed
Type:
Constituent

Method

Species / strain
Species / strain / cell type:
S. typhimurium TA 1535, TA 1537, TA 98 and TA 100
Metabolic activation:
with
Metabolic activation system:
hamster liver S9 (pre-incubation test)
Test concentrations with justification for top dose:
0, 4, 20, 100, 500, 2500, 5000 µg/plate
Vehicle / solvent:
- Vehicle(s)/solvent(s) used: DMSO
- Justification for choice of solvent/vehicle: solubility properties of the solvent
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 (TA 100, TA1535), 9-aminoacridine (TA 1537), 2-nitrofluorene (TA 98)
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 (TA 100, TA 1535, TA 1537), congo red (TA 98)
Remarks:
with metabolic activation
Details on test system and experimental conditions:
METHOD OF APPLICATION:
- plate incorporation assay: without metabolic activation
- preincubation assay: with metabolic activation with uninduced hamster liver S9 mix (30% (v/v)

DURATION
- Preincubation period: ca. 30 minutes at 30 °C
- Exposure duration: at least 48 hours

NUMBER OF REPLICATIONS: 3 plates per strain and dose level, including controls; two independent experiments for each of the two protocols (plate incorporation assay and pre-incubation assay)

Evaluation criteria:
A test compound is classified as mutagenic if it has either of the following effects:
- it produces at least a 2-fold increase in the mean number of revertants per plate of at least one of the tester strains over the mean number of revertants per plate of the appropriate vehicle control at complete bacterial background lawn
- it induces a dose-related increase in the mean number of revertants per plate of at least one of the tester strains over the mean number of revertants per plate of the appropriate vehicle control in at least two to three concentrations of the test compound at complete bacterial background lawn
Statistics:
Arithmetic means and standard deviation of the counted colonies were calculated, as well as the respective dose/control ratio.

Results and discussion

Test results
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:
no cytotoxicity
Vehicle controls validity:
valid
Untreated negative controls validity:
valid
Positive controls validity:
valid
Additional information on results:
TEST-SPECIFIC CONFOUNDING FACTORS
- Precipitation: visible precipitation of the test item at 500 µg/plate and above


Remarks on result:
other: all strains/cell types tested
Remarks:
Migrated from field 'Test system'.

Any other information on results incl. tables

The test item showed no mutagenic activity in both experiments (plate incorporation assay without metabolic activation and preincubation assay with metabolic activation).

Applicant's summary and conclusion

Conclusions:
Interpretation of results (migrated information):
negative

The test item did not exert mutagenic activity in the reverse bacterial mutation assay (plate incorporation assay without metabolic activation and preincubation assay with metabolic activation).
Executive summary:

Mutagenic activity of the test item was investigated in Salmonella typhimurium strains TA 1535, TA 1537, TA98 and TA100 without metabolic activation at concentrations of 0, 4, 20, 100, 500, 2500, 5000 µg/plate using the plate incorporation assay. Due to the test items characteristic as an azo-dye the test was also conducted using the Prival modification, i.e. testing the above mentioned bacterial strains in the preincubation assay with uninduced hamster liver S9 mix for metabolic activation. This test was performed using the concentrations 0, 4, 20, 100, 500, 2500, 5000 µg/plate.

The test item did not reveal any mutagenic activity under the conditions tested. The appropriate reference mutagenes showed distinct positive mutagenic effects.