Pentasodium 4-amino-6-[[5-[(4-amino-6-chloro-1,3,5-triazin-2-yl)amino]-2-sulphonatophenyl]azo]-3-[(2,5-disulphonatophenyl)azo]-5-hydroxynaphthalene-2,7-disulphonate

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:

key study

Study period:

From 01 October, 1992 to 05 November, 1992

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1992

Report date:

1992

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

Principles of method if other than guideline:

Guidelines followed

GLP compliance:

yes (incl. QA statement)

Type of assay:

bacterial reverse mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

Pentasodium 4-amino-6-[[5-[(4-amino-6-chloro-1,3,5-triazin-2-yl)amino]-2-sulphonatophenyl]azo]-3-[(2,5-disulphonatophenyl)azo]-5-hydroxynaphthalene-2,7-disulphonate

EC Number:

269-505-3

EC Name:

Pentasodium 4-amino-6-[[5-[(4-amino-6-chloro-1,3,5-triazin-2-yl)amino]-2-sulphonatophenyl]azo]-3-[(2,5-disulphonatophenyl)azo]-5-hydroxynaphthalene-2,7-disulphonate

Cas Number:

68259-02-9

Molecular formula:

C25H19ClN10O16S5.5Na

IUPAC Name:

pentasodium 4-amino-6-({5-[(4-amino-6-chloro-1,3,5-triazin-2-yl)amino]-2-sulfonatophenyl}diazenyl)-3-[(2,5-disulfonatophenyl)diazenyl]-5-hydroxynaphthalene-2,7-disulfonate

Test material form:

other: solid

Method

Target gene:

Histidine gene

Species / strain

Species / strain / cell type:

S. typhimurium TA 1535, TA 1537, TA 98, TA 100 and TA 102

Details on mammalian cell type (if applicable):

The strains are derived from S. typhimurium strain LT2 and due to a mutation in the histidine locus are histidine dependent. Additionally due to the "deep rough" (rfa-minus) mutation they possess a faulty lipopolysaccharide envelope which enables substances to penetrate the cell wall more easily. A further mutation causes a reduction in the activity of an excision repair system. The latter alteration includes mutational processes in the nitrate reductase and biotin genes produced in a UV-sensitive area of the gene named "uvrB-minus". In the strains TA 98, TA 100 and TA 102 the R-factor plasmid pKM 101 carries the ampicillin resistance marker. The strain TA 102 does not contain the uvrB"-mutation. Additionally TA 102 contains the multicopy plasmid pAQ1, which carries the hisG428 mutation and a tetracycline resistance gene. TA 102 contains the ochre mutation in hisG gene.

Additional strain / cell type characteristics:

not specified

Metabolic activation:

with and without

Metabolic activation system:

S9 mix

Test concentrations with justification for top dose:

33.3, 100, 333.3, 1000, 2500 and 5000 µg/plate

Vehicle / solvent:

- Vehicle(s)/solvent(s) used: Aqua bidest
- Justification for choice of solvent/vehicle: The solvent was chosen because of its solubility properties.

Controls

Controls 1

Untreated negative controls:

yes

Remarks:

(concurrent untreated)

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

sodium azide

Remarks:

(for TA 1535 and TA 100 without metabolic activation)

Controls 2

Untreated negative controls:

yes

Remarks:

(concurrent untreated)

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: 4-nitro-o-phenylene-diamine

Remarks:

(for TA 1537 and TA 98 without metabolic activation)

Controls 3

Untreated negative controls:

yes

Remarks:

(concurrent untreated)

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

methylmethanesulfonate

Remarks:

for TA 102 without metabolic activation)

Controls 4

Untreated negative controls:

yes

Remarks:

(concurrent untreated)

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: 2-aminoanthracene

Remarks:

(for all strains with metabolic activation)

Details on test system and experimental conditions:

METHOD OF APPLICATION: plate incorporation test (experiment I) and the pre-incubation test (experiment II)

For each strain and dose level, including the controls, a minimum of three plates were used.

Experiment 1: The following materials were mixed in a test tube and poured onto the selective agar plates:
- 100 µL: Test solution at each dose level, solvent control, negative control, or reference mutagen solution (positive control),
- 500 µL: S9 mix (for test with metabolic activation) or S9 mix substitution-buffer (for test without metabolic activation),
- 100 µL: Bacteria suspension (cf. test system, pre-culture of the strains),
- 2000 µL: Overlay agar

Experiment 2: In the pre-incubation assay 100 µL test solution, 500 µL S9 mix/S9 mix substitution buffer and 100 µL bacteria suspension were mixed. After pre-incubation 2 mL overlay agar was added to each tube. The mixture was poured on minimal agar plates. After solidification the plates were incubated upside down for at least 48 h at 37 °C in the dark.

Evaluation criteria:

The generally accepted conditions for the evaluation of the results are: corresponding background growth on both negative control and test plates as well as normal range of spontaneous reversion rates. Due to international guidelines a statistical evaluation of the results is recommended. However, no evaluated statistical procedure can be recommended for analysis of data from the bacterial assays at this time.
A test substance is considered as positive if either a dose related or reproducible increase in the number of revertants or a significant and reproducible increase for at least one test concentration is induced.
A test substance producing neither a dose related and reproducible increase in the number of revertants nor a significant and reproducible positive response at any one of the test points is considered non-mutagenic in this system.
A significant response is described as follows: A test substance is considered as mutagenic if in strain TA 100 and TA 102 the number of reversions is at least twice as high and in strains TA 1535, TA 1537, and TA 98 it is at least three times higher as compared to the spontaneous reversion rate. Also, a dose-dependent and reproducible increase in the number of revertants is regarded as an indication of possibly existing mutagenic potential of the test substance regardless whether the highest dose induced the above described enhancement factors or not.

Statistics:

No data

Results and discussion

Test results

Key result

Species / strain:

S. typhimurium TA 1535, TA 1537, TA 98, TA 100 and TA 102

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Remarks:

(occurred in strain TA 1537 without metabolic activation at the highest concentration in experiment I)

Vehicle controls validity:

valid

Untreated negative controls validity:

not examined

Positive controls validity:

valid

Additional information on results:

A slight toxic effect, evidenced by a reduction in the number of revertants, occurred in strain TA 1537 without metabolic activation at the highest concentration in experiment I. The plates incubated with the test substance showed normal background growth up to 5000 µg/plate with and without S9 mix in all strains used. No substantial increases in revertant colony numbers of any of the five tester strains were observed at any dose level, either in the presence or absence of metabolic activation. There was also no tendency of higher mutation rates with increasing concentrations in the range below the generally acknowledged border of significance.

Remarks on result:

other: all strains/cell types tested

Any other information on results incl. tables

None

Applicant's summary and conclusion

Conclusions:

The test substance was considered to be non-mutagenic in a Salmonella typhimurium reverse mutation assay.

Executive summary:

An in vitro study was performed to investigate the potential of the test substance (of ca. 100 % purity) to induce gene mutations according to OECD Guideline 471 and EU Method B.14 in compliance with GLP.

The assay was performed in two independent experiments, both with and without liver metabolic activation. Experiment I was performed as a plate incorporation assay and Experiment II as a pre-incubation assay using Salmonella typhimurium strains TA 1535, TA 1537, TA 98, TA 100, and TA 102. Each concentration, including the controls, was tested in triplicate. The substance was tested up to 5000 µg/plate.

A slight toxic effect, evidenced by a reduction in the number of revertants, occurred in strain TA 1537 without metabolic activation at the highest concentration in Experiment I. The plates incubated with the test substance showed normal background growth up to 5000 µg/plate with and without S9 mix in all strains used. No substantial increases in revertant colony numbers of any of the five tester strains were observed at any dose level.

Under the study conditions, the test substance was considered to be non-mutagenic in this Salmonella typhimurium reverse mutation assay.