Registration Dossier

Diss Factsheets

Toxicological information

Genetic toxicity: in vitro

Currently viewing:

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:
From 2 MAY 2006 to 12 MAY 2006
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Guideline study (OECD TG 471)

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2006
Report date:
2006

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
OECD Guideline 471 (Bacterial Reverse Mutation Assay)
Deviations:
no
GLP compliance:
yes
Type of assay:
bacterial reverse mutation assay

Test material

Constituent 1
Chemical structure
Reference substance name:
Dimethyl 5-[[1-[[(2,3-dihydro-2-oxo-1H-benzimidazol-5-yl)amino]carbonyl]-2-oxopropyl]azoterephthalate
EC Number:
249-955-7
EC Name:
Dimethyl 5-[[1-[[(2,3-dihydro-2-oxo-1H-benzimidazol-5-yl)amino]carbonyl]-2-oxopropyl]azoterephthalate
Cas Number:
29920-31-8
Molecular formula:
C21H19N5O7
IUPAC Name:
dimethyl 5-({2-oxo-1-[(2-oxo-2,3-dihydro-1H-benzimidazol-5-yl)carbamoyl]propyl}diazenyl)isophthalate
Test material form:
solid: nanoform

Method

Species / strainopen allclose all
Species / strain / cell type:
S. typhimurium TA 1535, TA 1537, TA 98 and TA 100
Species / strain / cell type:
E. coli WP2 uvr A
Metabolic activation:
with and without
Metabolic activation system:
rat liver S9 (induced with phenobarbital/beta-naphtoflavone; experiment I); hamster liver S9 (non-induced; experiment II)
Test concentrations with justification for top dose:
Experiment I: 3; 10; 33; 100; 333; 1000; 2500; and 5000 µg/plate.
Experiment II: 10; 33; 100; 333; 1000; 2500; and 5000 µg/plate
Vehicle / solvent:
- Vehicle(s)/solvent(s) used: DMSO
- Justification for choice of solvent/vehicle: solubility properties of the solvent and its relative non-toxicity to the bacteria
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 1535 and TA 100), 4-Nitro-o-phenylene-diamine (TA 1537 and TA 98), methyl methane sulfonate (WP2 uvrA)
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 (for all strains)
Remarks:
with metabolic activation (rat liver S9)
Untreated negative controls:
yes
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
other: 2-aminoanthracene (TA 1535, TA 100, TA 1537, WP2 uvrA), congo red (TA 98)
Remarks:
with metabolic activation (hamster liver S9)
Details on test system and experimental conditions:
METHOD OF APPLICATION:
Experiment I: plate incorporation assay without and with induced rat liver S9 mix (induction with phenobarbital/beta-naphthoflavone)
Experiment II: preincubation assay without and with non-induced hamster liver S9 mix

DURATION
- Preincubation period: Experiment II: 30° C for 30 minutes
- Exposure duration: at least 48 hours at 37° C

NUMBER OF REPLICATIONS: 3 plates per strain and dose level, including the control
Evaluation criteria:
A test item is considered as a mutagen if a biologically relevant increase in the number of revertants exceeding the threshold of twice (strains TA 98, TA 100, WP2 uvrA) or thrice (strains TA 1535, TA 1537) the colony count of the corresponding solvent colony is observed.
A dose dependent increase is considered biologically relevant if the threshold is exceeded at more than one concentration.
An increase exceeding the threshold at only one concentration is judged as biologically relevant if reproduced in an independent second experiment. A dose dependent increase in the number of revertant colonies below the thresshold is regarded as an indication of mutagenic potential if reproduced in an independent second experiment. However, whenever the colony counts remain within the historical range of negative annd solvent controls such an increase is not considered biologically relevant.
Statistics:
Arithmetic means and standard deviation of the counted colonies were calculated.

Results and discussion

Test resultsopen allclose all
Key result
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:
cytotoxicity
Remarks:
in strain TA1537, TA98, TA100 (exp. I, without S9, starting from 2500 µg/plate); strain TA1537, TA98 (exp. II, without S9, starting from 1000 µg/plate);TA 100 exp. II, without S9, starting from 333 µg/plate); TA1537, TA98 (exp. II, with S9, 5000 µg/plate)
Vehicle controls validity:
valid
Untreated negative controls validity:
not examined
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
Remarks:
noted in exp. II, without S9 mix, at 5000 µg/plate
Vehicle controls validity:
valid
Untreated negative controls validity:
not examined
Positive controls validity:
valid
Additional information on results:
TEST-SPECIFIC CONFOUNDING FACTORS
- Precipitation: The test item precipitated in the overlay agar from 333 pg/plate up to 5000 µg/plate in experiment I. In experiment II, precipitation was observed from 100 µg/plate up to 5000 µg/plate. The undissolved particles had no influence on the data recording.

COMPARISON WITH HISTORICAL CONTROL DATA:
In experiment I, the data in the negative control with metabolic activation of strain WP2uvrA were slightly above our historical control range. Since this deviation is rather small, this effect is considered to be based upon biologically irrelevant fluctuations in the number of colonies.

ADDITIONAL INFORMATION ON CYTOTOXICITY:
Cytotoxicity was observed in
- strain TA1537, TA98, TA100 (exp. I, without S9, starting from 2500 µg/plate);
- strain TA1537, TA98 (exp. II, without S9, starting from 1000 µg/plate);
- strain TA 100 exp. II, (without S9, starting from 333 µg/plate);
- strain TA1537, TA98 (exp. II, with S9, 5000 µg/plate) and
- E.coli strain WP2 uvrA (exp. II, without S9 mix, at 5000 µg/plate)
Remarks on result:
other: all strains/cell types tested

Applicant's summary and conclusion

Conclusions:
Interpretation of results (migrated information):
negative

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

Mutagenic activity of the test item was investigated in Salmonella typhimurium strains TA 1535, TA 1537, TA98 and TA100 as well as Escherichia coli strain WP2 uvrA with (induced rat liver S9 mix) and without metabolic activation at concentrations of 3, 10, 33, 100, 333, 1000, 2500 and 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 without and with uninduced hamster liver S9 mix for metabolic activation. This test was performed using the concentrations 10, 33, 100, 333, 1000, 2500 and 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.