p-[(5-cyano-1,6-dihydro-2-hydroxy-1,4-dimethyl-6-oxo-3-pyridyl)azo]-N-(2-ethylhexyl)benzamide

Genetic toxicity: in vitro

Administrative data

Endpoint:

in vitro gene mutation study in bacteria

Remarks:

Type of genotoxicity: gene mutation

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

19 Apr 1991

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Remarks:

No Prival modification applied although substance is an azo dye.

Data source

Reference

Reference 1

Reference Type:

study report

Title:

Unnamed

Year:

1991

Report date:

1991

Reference 2

Reference Type:

study report

Title:

Unnamed

Year:

1991

Report date:

1991

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method B.13/14 (Mutagenicity - Reverse Mutation Test Using Bacteria)

Deviations:

no

GLP compliance:

yes

Type of assay:

bacterial reverse mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

p-[(5-cyano-1,6-dihydro-2-hydroxy-1,4-dimethyl-6-oxo-3-pyridyl)azo]-N-(2-ethylhexyl)benzamide

EC Number:

250-205-6

EC Name:

p-[(5-cyano-1,6-dihydro-2-hydroxy-1,4-dimethyl-6-oxo-3-pyridyl)azo]-N-(2-ethylhexyl)benzamide

Cas Number:

30449-81-1

Molecular formula:

C23H29N5O3

IUPAC Name:

p-[(5-cyano-1,6-dihydro-2-hydroxy-1,4-dimethyl-6-oxo-3-pyridyl)azo]-N-(2-ethylhexyl)benzamide

Test material form:

solid: particulate/powder

Method

Species / strain

Species / strain 1

Species / strain / cell type:

S. typhimurium TA 1535, TA 1537, TA 98 and TA 100

Additional strain / cell type characteristics:

other: histidine dependent

Species / strain 2

Species / strain / cell type:

E. coli WP2 uvr A

Additional strain / cell type characteristics:

other: tryptophan dependent

Metabolic activation:

with and without

Metabolic activation system:

rat liver homogenate

Test concentrations with justification for top dose:

0; 20; 100; 500; 2500; 5000 µg/plate

Vehicle / solvent:

DMSO

Controls

Controls 1

Untreated negative controls:

yes

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: 2-aminoanthracene

Remarks:

all strains with S9

Controls 2

Untreated negative controls:

yes

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: N-methyl-N-nitro-N-nitrosoguanidine

Remarks:

TA1535, TA100, E. coli WP2 uvrA w/o S9

Controls 3

Untreated negative controls:

yes

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: 4-nitro-o-phenylendiamine

Remarks:

TA98 w/o S9

Controls 4

Untreated negative controls:

yes

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

9-aminoacridine

Remarks:

TA1537 w/o S9

Details on test system and experimental conditions:

METHOD OF APPLICATION:
1. Plate incorporation
- Incubation: 37°C 48 to 72 hours
2. Preincubation
- Preincubation: 37°C for 20 minutes
- Incubation: 37°C 48 to 72 hours

- Triplicate plating


DETERMINATION OF CYTOTOXICITY
- decrease in number of revertants
- clearing or diminuation of background lawn
- reduction of titer

Evaluation criteria:

Positive: dose-related and reproducible increase in number of revertant colonies
- doubling of spontaneous mutation rate in at least one tester strains either with or without S9

Negative: number of revertants are within historical negative control range in two independent experiments

Results and discussion

Test results

Test results 1

Key result

Species / strain:

other: TA 1535, TA 100, TA 1537, TA 98

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

Test results 2

Key result

Species / strain:

E. coli WP2 uvr A

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: from 100 µg/plate onwards

Remarks on result:

other: No effect in preincubation and mutagenicity test

Applicant's summary and conclusion

Conclusions:

The test item did not lead to an increase of the number of revertant colonies with or without S9 in the standard plate and preincubation test with Salmonella typhimurum and Escherichia coli. The substance is considered to be not mutagenic in bacterial reverse mutation assays, neither in absence nor presence of a metabolic activation system.