Chromium, complexes with 2-amino-4(or 5)-nitrophenol coupled with diazotized 4-amino-3-hydroxy-7-nitro-1-naphthalenesulfonic acid and 2-naphthalenol, sodium salts

Genetic toxicity: in vitro

Administrative data

Endpoint:

in vitro gene mutation study in mammalian cells

Type of information:

other: read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Justification for type of information:

Section 13: see the attached document containing the justification for the read-across.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1995

Report date:

1995

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 476 (In Vitro Mammalian Cell Gene Mutation Test)

GLP compliance:

yes (incl. QA statement)

Type of assay:

mammalian cell gene mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

Analogue Substance #2

IUPAC Name:

Analogue Substance #2

Test material form:

solid: particulate/powder

Method

Species / strain

Species / strain / cell type:

Chinese hamster lung fibroblasts (V79)

Details on mammalian cell type (if applicable):

clone 65/3Origin: Dr. D. Wild, Freiburg, Germany

Metabolic activation:

with

Metabolic activation system:

Post mitochondrial supernatant (S9 fraction) from Aroclor 1254 induced rat liver

Test concentrations with justification for top dose:

Cytotoxicity test: range with metabolic activation: 0.24 to 500.0 µg/ml; range without metabolic activation: 0.24 to 500.0 µg/ml.
Mutagenicity test original experiment: range with metabolic activation: 18.52 to 500.0 µg/ml; range without metabolic activation: 14.81 to 400.0 µg/ml.
Confirmatory experiment: range with metabolic activation: 18.52 to 500.0 µg/ml; range without metabolic activation: 12.96 to 350.0 µg/ml.

Vehicle / solvent:

Dimethylsulfoxide (suspension): since the test substance was insoluble in all common solvents, it had to be prepared as a suspension in DMSO. The highest suitable concentration of test substance in DMSO was determined in a preliminary solubilisation test to be 50.0 mg/ml. Lower concentrations of the test substance were obtained by appropriate dilution of the stock suspension with DMSO. The respective suspensions were added 1:100 to the cell culture medium. The final concentration of DMSO in the culture medium was 1%. The highest concentration caused a homogenious turbidity after 100-fold dilution with culture medium as determined in the preliminary solubility test by microscopic evaluation. Due to the dense black staining by the test compound, observation of the cultures with the naked eye did not allow todecide whether the compound precipitated or not. It was therefore not determined which concentrations caused the formation of precipitates in the toxicity and mutagenicity tests. The test substance suspensions were prepared immediately before the start of the test.

Controls

Untreated negative controls:

yes

Remarks:

dimethylsulfoxide

Positive controls:

yes

Positive control substance:

N-dimethylnitrosamine

ethylmethanesulphonate

Remarks:

N-dimethylnitrosamine with metabolic activation, ethylmetanesulphonate without metabolic activation

Evaluation criteria:

All mutant frequencies are normalized to a virtual cloning efficiency of 100% at the end of the expression period. If the cloning efficiency of the viability cultures is lower than 15%, the corresponding mutant frequency is usually not calculated, owing to the high statistical insignificance of theresult. For every concentration a mean mutant factor, which is defined as the ratio of the mean mutant frequencies of the treated cultures with the mean mutant frequencies of the solvent control cultures, will be calculated. Criteria for a positive responseThe test substance will be considered to be mutagenic if: the assay is valid, the mutant frequency at one or more concentrations is significantly greater than that of the negative control and the number of normalized mutant clones in the treated and untreated cultures differs by more than 20, there is a significant dose-relationship as indicated by the linear trend analysis and the effects described above are reproducible.

Statistics:

Statistical significance of mutant frequencies was carried out according to the UKEMS guidelines.

Results and discussion

Test results

Species / strain:

Chinese hamster lung fibroblasts (V79)

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Vehicle controls validity:

not examined

Untreated negative controls validity:

valid

True negative controls validity:

not examined

Positive controls validity:

valid

Applicant's summary and conclusion

Conclusions:

Negative. The test substance was tested for in vitro gene mutation in mammalian cells following OECD 476. Under the experimental conditions the test substance did not show any mutagenic potential.

Executive summary:

The test substance was tested for in vitro gene mutation in mammalian cells following OECD 476. Chinese Hamster lung fibroblasts V79 were exposed to the test substance with and without metabolic activation at dose ranging up to 500 µg/l and 400 µg/l respectively. After the expression period, the mutant frequency was determined by 6-thioguanine screening and the substance resulted not having mutagenic potential.