Barium bis[2-[(2-hydroxynaphthyl)azo]naphthalenesulphonate]

Genetic toxicity: in vitro

Administrative data

Endpoint:

in vitro cytogenicity / chromosome aberration study in mammalian cells

Type of information:

experimental study

Adequacy of study:

key study

Study period:

october 1989

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1989

Report date:

1989

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 473 (In Vitro Mammalian Chromosome Aberration Test)

GLP compliance:

yes

Type of assay:

in vitro mammalian chromosome aberration test

Test material

Test material information

Constituent 1

Reference substance name:

Barium bis[2-chloro-5-[(2-hydroxy-1-naphthyl)azo]toluene-4-sulphonate]

EC Number:

225-935-3

EC Name:

Barium bis[2-chloro-5-[(2-hydroxy-1-naphthyl)azo]toluene-4-sulphonate]

Cas Number:

5160-02-1

Molecular formula:

C17H13ClN2O4S.1/2Ba

IUPAC Name:

barium bis{5-chloro-2-[(2-hydroxy-1-naphthyl)diazenyl]-4-methylbenzenesulfonate}

Method

Species / strain

Species / strain / cell type:

Chinese hamster lung fibroblasts (V79)

Metabolic activation:

with and without

Metabolic activation system:

S9 mix of Aroclor induced rat liver

Test concentrations with justification for top dose:

30, 150 and 300 microgramm/ml

Vehicle / solvent:

DMSO

Controls

Untreated negative controls:

yes

Negative solvent / vehicle controls:

yes

Positive controls:

yes

Positive control substance:

cyclophosphamide

ethylmethanesulphonate

Details on test system and experimental conditions:

METHOD OF APPLICATION: in medium

DURATION
- Exposure duration: 4 and 18h
- Fixation time (start of exposure up to fixation or harvest of cells): 4.5 15.5 and 25.5 h after the start of the treatment colcemide was added (0.04 ug/ml culture medium), 2.5 h later the cells were trypsinised

SPINDLE INHIBITOR (cytogenetic assays): colcemide
STAIN (for cytogenetic assays): 2 % orcein solution

NUMBER OF REPLICATIONS: singly

NUMBER OF CELLS EVALUATED: 100 metaphases per concentration

DETERMINATION OF CYTOTOXICITY
- The toxi city of the test substance was determi ned ina pre1iminary experiment by establishing the concentration-related plating efficiency

Evaluation criteria:

The evaluation of the results was performed as follows:
- the test substance is classified as mutagenic if it induces a significantly increased aberration rate as compared with the negative controls with one of the concentrations tested
- the significance is obvious either by an enhancement of the rate clearly exceeding the control range or it is proven by adequate biometry (Binomial statistic with Fisher's exact test)
- the test substance is cl ass ifi ed as mutagen i c if there is a reproducible concentration related increase in the aberration rate
- the test substance is classified as not mutagenic when it tests negatively both with and without metabolic activation.

Statistics:

Not necessary to perform as all mean chromosome aberration rates after treatment wit the test article were in the range of the negative control value.

Results and discussion

Test results

Species / strain:

Chinese hamster lung fibroblasts (V79)

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

Positive controls validity:

valid

Additional information on results:

RANGE-FINDING/SCREENING STUDIES:
A preliminary cytotoxicity experiment was performed in order to select appropriate dose leve1s for the mutagenicity study. The test substance produced a signifiant cytotoxic effect (reduction of plating efficiency) with and without metabolic activation from 400 ug/ml up to the limit of solubility (500ug/ml).

Applicant's summary and conclusion

Conclusions:

Interpretation of results:
negative

In conclusion the test substance does not induce chromosome mutations (=aberrations) in V79 Chinese hamster cells, neither in the presence nor in the abse ce of a metabolic activation system, under the experimental conditions described.