1-[(2-chloro-4-nitrophenyl)azo]-2-naphthol

Genetic toxicity: in vitro

Administrative data

Endpoint:

in vitro cytogenicity / chromosome aberration study in mammalian cells

Remarks:

Type of genotoxicity: chromosome aberration

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2013

Reliability:

1 (reliable without restriction)

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2013

Report Date:

2013

Materials and methods

Test guideline

Qualifier:

according to

Guideline:

OECD Guideline 473 (In Vitro Mammalian Chromosome Aberration Test)

Deviations:

no

GLP compliance:

yes (incl. certificate)

Type of assay:

in vitro mammalian chromosome aberration test

Test material

Reference

Name:

Unnamed

Type:

Constituent

Test material form:

solid: particulate/powder

Remarks:

migrated information: powder

Results and discussion

Test results

Species / strain:

lymphocytes: Human

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Applicant's summary and conclusion

Conclusions:

Interpretation of results (migrated information):negativeC.I. Pigment Red 4 is considered to be non-clastogenic to human lymphocytes in vitro.

Executive summary:

Introduction.

This report describes the results of an in vitro study for the detection of structural chromosomal aberrations in cultured mammalian cells. It supplements microbial systems insofar as it identifies potential mutagens that produce chromosomal aberrations rather than gene mutations (Scott et al, 1990). The method used was designed to be compatible with that described in the OECD Guidelines for Testing of Chemicals (1997) No. 473 "Genetic Toxicology: Chromosome Aberration Test", Method B10 of Commission Regulation (EC) No. 44012008 of 30 May 2008 and the USA EPA OPPTS guideline 40 CFR 799.9537. The study design also meets the requirements of the UK Department of Health Guidelines for Testing of Chemicals for Mutagenicity.

Methods.

Duplicate cultures of human lymphocytes, treated with the test item, were evaluated for chromosome aberrations at up to four dose levels, together with vehicle and positive controls. Four treatment conditions were used for the study; i.e. In Experiment 1, 4 hours in the presence of an induced rat liver homogenate metabolising system (S9), at a 2% final concentration with cell harvest after a 20-hour expression period and a 4 hours exposure in the absence of metabolic activation (S9) with a 20-hour expression period. In Experiment 2, the 4 hours exposure with addition of S9 was repeated (using a 1% final S9 concentration), whilst in the absence of metabolic activation the exposure time was increased to 24 hours.

The dose levels used in the main experiments were selected using data from the preliminary toxicity test and were as follows:

Test item (ug/ml) 25, 50, 100, 200, 400, 800

Results.

All vehicle (solvent) controls had frequencies of cells with aberrations within the range expected for normal human lymphocytes. All the positive control items induced statistically significant increases in the frequency of cells with aberrations indicating the satisfactory performance of the test and of the activity of the metabolising system. The test item did not induce any statistically significant increases in the frequency of cells with aberrations, in either the absence or presence of a liver enzyme metabolising system in either of two separate experiments. The maximum dose tested was limited by formulation difficulties and was also limited by precipitate of the test item occurring on the slides at the maximum dose and restricting the ability to accurately Score metaphases.

Conclusion.

The test item was considered to be non-clastogenic to human lymphocytes in vitro.