Disodium 7,7'-(carbonyldiimino)bis[4-hydroxy-3-(phenylazo)naphthalene-2-sulphonate]

Endpoint summary

Key value for chemical safety assessment

Genetic toxicity in vitro

Description of key information

Not mutagenic

Link to relevant study records

Reference

Endpoint:

in vitro gene mutation study in bacteria

Remarks:

Type of genotoxicity: gene mutation

Type of information:

other: read across from similar substance

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

Study well documented, test procedure in accordance with OECD 471 methods, meets generally accepted scientific principles, acceptable for assessment. GLP guideline study with acceptable restrictions (E. coli WP2 uvrA or S. typhimurium TA 102 missing).

Qualifier:

according to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

GLP compliance:

yes

Type of assay:

bacterial reverse mutation assay

Species / strain / cell type:

S. typhimurium, other: TA 1535, TA 1537, TA 1538, TA 98, TA 100

Metabolic activation:

with and without

Metabolic activation system:

Aroclor-induced rat liver S-9 mix

Test concentrations with justification for top dose:

10.0; 100.0; 333.3; 1000.0; and 5000.0 µg/plate

Vehicle / solvent:

- Vehicle/solvent used: A. dest.- Justification for choice of solvent/vehicle: The solvent was chosen because of its solubility properties.

Untreated negative controls:

yes

Negative solvent / vehicle controls:

yes

Positive controls:

yes

Remarks:

W/o S-9: 10 µg/plate sodium azide (TA 1535, Ta 100), 50 µg/plate 4-NOPD (TA 1537, TA 1538, TA 98); w/ S-9: 10 µg/plate 2-AA (all strains)

Details on test system and experimental conditions:

METHOD OF APPLICATION: in agar (plate incorporation)NUMBER OF REPLICATIONS: The assay was performed in two independent experiments, using identical procedures, both with and without liver microsomal activation. Each concentration, including the controls, was tested in triplicate.DETERMINATION OF CYTOTOXICITY: Toxicity of the test article may be evidenced by a reduction in the number of spontaneous revertants, a clearing of the bacterial background lawn, or by degree of survival of treated cultures.

Evaluation criteria:

The generally accepted conditions for the evaluation of the results are:- corresponding background growth on both negative control and test plates- normal range of spontaneous reversion rates.A test article is considered as positive if either a significant dose-related increase in the number of revertants or a significant and reproducible increase for at least one test concentration is induced.A test article producing neither a significant dose-related 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 test article is considered as mutagen if in strain TA 100 the number of reversions is at least twice as high and in strains TA 1535, TA 1537, TA 1538, and TA 98 it is at least three times higher as compared to the spontaneous reversion rate.Also, a dose-dependent increase in the number of revertants is regarded as an indication of possibly existing mutagenic potential of the test article regardless whether the highest dose induced the above described enhancement factors or not.

Species / strain:

S. typhimurium, other: TA 1535, TA 1537, TA 1538, TA 98, TA 100

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity nor precipitates, but tested up to recommended limit concentrations

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Additional information on results:

RANGE-FINDING/SCREENING STUDIES:To evaluate the toxicity of the test article a pre-study was performed with strains TA 98 and TA 100. The plates with the test article showed normal background growth up to 5000.0 µg/plate in strain TA 98 and TA 100, respectively. According to the dose selection criteria, the test article was tested at the following concentrations: 10.0; 100.0; 333.3; 1000.0; and 5000.0 µg/plate.ADDITIONAL INFORMATION ON CYTOTOXICITY:In both experiments no toxic effects, normally evidenced by a reduction in the number of revertants, occurred in the test groups with and without metabolic activation in all strains used. The plates incubated with the test article showed normal background growth up to 5000.0 µg/plate with and without S9 mix in all strains used.

Conclusions:

Interpretation of results (migrated information):negativeUnder the experimental conditions reported, the test article did not induce point mutations by base pair changes or frameshifts in the genome of the strains used. Therefore, the test article is considered to be non-mutagenic in this Salmonella typhimurium reverse mutation assay.

Executive summary:

The study followed OECD guideline 471 (1981) and the principles of GLP. In the presence and absence of rat liver S-9 microsomal activation system and at doses of up to 5000 μg/plate, S. typhimurium strains TA 98, TA 100, TA 1535, TA 1537 and TA 1538 did not show an increased number of revertant colonies. In addition, there was no indication of toxicity to bacteria. Therefore, no evidence of a mutagenic potential was associated with the test substance. The purity of the test item was 94.6%. A. dest. was used as a vehicle.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (negative)

Genetic toxicity in vivo

Description of key information

Not mutagenic

Link to relevant study records

Reference

Endpoint:

in vivo mammalian somatic cell study: cytogenicity / erythrocyte micronucleus

Remarks:

Type of genotoxicity: chromosome aberration

Type of information:

other: read across from similar substance

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Reason / purpose for cross-reference:

reference to same study

Qualifier:

according to guideline

Guideline:

OECD Guideline 474 (Mammalian Erythrocyte Micronucleus Test)

Deviations:

not specified

GLP compliance:

not specified

Type of assay:

micronucleus assay

Species:

mouse

Strain:

NMRI

Sex:

male/female

Route of administration:

oral: unspecified

Vehicle:

in 1 % carboxymethylcellulose

Remarks:

Doses / Concentrations:
5000 mg/kg
Basis:
nominal conc.

No. of animals per sex per dose:

5/sex/group

Positive control(s):

Cyclophosphamide

Tissues and cell types examined:

Bone marrow samples were scored for polychromatic erythrocytes containing micronuclei at 24, 48 and 72 hours post-dosing.

Sex:

male/female

Genotoxicity:

negative

Toxicity:

yes

Remarks:

some cytotoxicity

Negative controls validity:

not valid

Positive controls validity:

valid

Conclusions:

Interpretation of results (migrated information): negative
Under experimental conditions substance did not appear to induce micronuclei.

Executive summary:

Substance was investigated for its potential to induce micronuclei in polychromatic erythrocytes in mouse bone marrow. NMRI mice (5/sex/group) were given the test substance (in 1% carboxymethylcellulose) as a single oral dose at 5000 mg/kg. Bone marrow samples were scored for polychromatic erythrocytes containing micronuclei at 24, 48 and 72 hours post-dosing. The ratio of polychromatic to normochromatic erythrocytes indicated some cytotoxicity at the dose level used. However, the number of cells with micronuclei in the tested animals was similar that in control animals. Cyclophosphamide was used as a positive control.

Additional information

On the base of results of the tests performed on similar substances both on in vitro and on in vivo, Direct Orange 26 can be considered not mutagen.

Justification for classification or non-classification

According to CLP regulation (EC1272/2008) Direct Orange 26 is not classified for genetic toxicity.