Reaction mass of 5,5'-[vinylenebis[(3-sulpho-p-phenylene)azo]]bis[3-methylsalicylic] acid, potassium salt, compound with 2,2',2''-nitrilotriethanol and potassium 5-amino-3-{[4-(2-{4-[(7-amino-1-hydroxy-3-sulfo-2-naphthyl)diazenyl]-2-sulfophenyl}vinyl)-3-sulfophenyl]diazenyl}-4-hydroxy-7-sulfonaphthalene-2-sulfonate - 2,2',2''-nitrilotriethanol (1:1) and 3,3'-[vinylenebis[(3-sulpho-p-phenylene)azo]]bis[5-amino-4-hydroxynaphthalene-2,7-disulphonic] acid, potassium salt, compound with 2,2',2''-nitrilotriethanol and 3,3'-[vinylenebis[(3-sulpho-p-phenylene)azo]]bis[6-amino-4-hydroxynaphthalene-2-sulphonic] acid, potassium salt, compound with 2,2',2''-nitrilotriethanol

Genetic toxicity: in vitro

Administrative data

Endpoint:

in vitro gene mutation study in bacteria

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2017

Report date:

2017

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Type of assay:

bacterial reverse mutation assay

Test material

Test material information

Constituent 1

Test material form:

solid

Method

Species / strain

Species / strain / cell type:

S. typhimurium TA 1535, TA 1537, TA 98, TA 100 and E. coli WP2

Metabolic activation:

with and without

Metabolic activation system:

S9 mix from male Wistar rats livers and S9 mix from male Syrian golden hamstes livers.

Test concentrations with justification for top dose:

0; 33; 100; 333; 1000; 2950 and 5900 µg/plate (with and without S9 mix) (SPT und Prival)

Vehicle / solvent:

- Vehicle(s)/solvent(s) used: DMSO

Controls

Untreated negative controls:

yes

Negative solvent / vehicle controls:

yes

Positive controls:

yes

Positive control substance:

4-nitroquinoline-N-oxide

9-aminoacridine

congo red

other: 2-aminoanthracene, N-methyl-N'-nitro-N-nitrosoguanidine, 4-nitro-o-phenylenediamine

Details on test system and experimental conditions:

Test substance preparation:
The test substance was weighed and topped up with the chosen vehicle to achieve the required concentration of the stock solution. The test substance was dissolved in dimethyl sulfoxide (DMSO). To achieve a clear solution of the test substance in the vehicle, the test substance preparation was treated with ultrasonic waves and was shaken thoroughly. The further concentrations were diluted from the stock solution according to the planned doses. All test substance formulations were prepared immediately before administration.

Standard plate test:
Salmonella typhimurium:
Test tubes containing 2-mL portions of soft agar (overlay agar), which consists of 100 mL agar (0.8% [w/v] agar + 0.6% [w/v] NaCl) and 10 mL amino acid solution (minimal amino acid solution for the determination of mutants: 0.5 mM histidine + 0.5 mM biotin) were kept in a water bath at about 42 - 45°C, and the remaining components were added in the following order:
0.1 mL test solution or vehicle (negative control); 0.1 mL fresh bacterial culture; 0.5 mL S9 mix (with metabolic activation) or 0.5 mL phosphate buffer (without metabolic activation). After mixing, the samples were be poured onto Minimal glucose agar plates (Moltox Molecular Toxicology, Inc.; Boone, NC 28607; USA) within approx. 30 seconds. After incubation at 37°C for 48 – 72 hours in the dark, the bacterial colonies (his+ revertants) were counted. The colonies were counted using the Sorcerer Image Analysis System with the software program Ames Study Manager (Perceptive Instruments Ltd., Haverhill, UK). Colonies were counted manually, if precipitation of the test substance hinders the counting using the Image Analysis System.
Escherichia coli:
Test tubes containing 2-mL portions of soft agar (overlay agar), which consists of 100 mL agar (0.8% [w/v] agar + 0.6% [w/v] NaCl) and 10 mL amino acid solution (minimal amino acid solution for the determination of mutants: 0.5 mM tryptophan) were kept in a water bath at about 42 - 45°C, and the remaining components were added in the following order:
0.1 mL test solution or vehicle (negative control); 0.1 mL fresh bacterial culture; 0.5 mL S9 mix (with metabolic activation) or 0.5 mL phosphate buffer (without metabolic activation). After mixing, the samples were be poured onto Minimal glucose agar plates (Moltox Molecular Toxicology, Inc.; Boone, NC 28607; USA) within approx. 30 seconds. After incubation at 37°C for 48 – 72 hours in the dark, the bacterial colonies (trp+ revertants) were counted. The colonies were counted using the Sorcerer Image Analysis System with the software program Ames Study Manager (Perceptive Instruments Ltd., Haverhill, UK). Colonies were counted manually, if precipitation of the test substance hinders the counting using the Image Analysis System.

Prival Preincubation Test:
The experimental procedure is based on the method described by Yahagi et al. (7) and Matsushima et al. (8) and has been modified further to include reductive conditions by Prival et al. (9,10). 0.1 mL test solution or vehicle (negative control), 0.1 mL bacterial suspension and 0.5 mL S9 mix (with metabolic activation) or phosphate buffer (without metabolic activation) were incubated at 30°C for 30 minutes using a shaker. Subsequently, 2 mL soft agar which consists of 100 mL agar (0.8% [w/v] agar + 0.6% [w/v] NaCl) and 10 mL amino acid solution (minimal amino acid solution for the determination of mutants: 0.5 mM histidine + 0.5 mM biotin or 0.5 mM tryptophan) were added. After mixing, the samples were poured onto the
Vogel-Bonner agar plates (minimal glucose agar plates) within approx. 30 seconds.
Composition of the minimal glucose agar: 980 mL purified water; 20 mL Vogel-Bonner E medium (0.04 M MgSO4, 0.52 M citric acid, 2.87 M K2HPO4, 0.87 M NaNH4HPO4); 15 g Difco bacto agar; 5 g D-glucose, monohydrate. After incubation at 37°C for 48 – 72 hours in the dark, the bacterial colonies were counted. The colonies were counted using the Sorcerer Image Analysis System with the software program Ames Study Manager (Perseptive Instruments Ltd., Haverhill, UK). Colonies were counted manually, if precipitation of the test substance hindered the counting using the Image Analysis System.

Evaluation criteria:

The test substance was considered positive in this assay if the following criteria were met:
• A dose-related and reproducible increase in the number of revertant colonies, i.e. at least doubling (bacteria strains with high spontaneous mutation rate, like TA 98, TA 100 and E.coli WP2 uvrA) or tripling (bacteria strains with low spontaneous mutation rate, like TA 1535 and TA 1537) of the spontaneous mutation rate in at least one tester strain either without S9 mix or after adding a metabolizing system.

Results and discussion

Test results

Species / strain:

other: TA 1535, TA 100, TA 1537, TA 98 and E.coli WP2 uvrA

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Any other information on results incl. tables

SOLUBILITY: No precipitation of the test substance was found with and without S9 mix.

TOXICITY: A weak bacteriotoxic effect was occasionally observed depending on the strain and test conditions from about 1000 μg/plate onward.

MUTAGENICITY: A biologically relevant increase in the number of his+ or trp+ revertants (factor ≥ 2: TA 100, TA 98 and E.coli WP2 uvrA or factor ≥ 3: TA 1535 and TA 1537) was not observed in the

standard plate test or in the prival preincubation test without S9 mix or after the addition of a metabolizing system.

Applicant's summary and conclusion

Conclusions:

Under the experimental conditions of this study, the test substance Direct Black 18L NA active dye is not mutagenic in the Salmonella typhimurium/Escherichia coli reverse mutation assay in the absence and the presence of metabolic activation.