N,N'-(10,15,16,17-tetrahydro-5,10,15,17-tetraoxo-5H-dinaphtho[2,3-a:2',3'-i]carbazole-4,9-diyl)bis(benzamide)

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:

11 August 1981 and were completed on 21 September 1981.

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:

1981

Report date:

1981

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Deviations:

yes

Remarks:

ETAD Toxicological Method No 005

GLP compliance:

yes

Type of assay:

bacterial reverse mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

N,N'-(10,15,16,17-tetrahydro-5,10,15,17-tetraoxo-5H-dinaphtho[2,3-a:2',3'-i]carbazole-4,9-diyl)bis(benzamide)

EC Number:

205-044-6

EC Name:

N,N'-(10,15,16,17-tetrahydro-5,10,15,17-tetraoxo-5H-dinaphtho[2,3-a:2',3'-i]carbazole-4,9-diyl)bis(benzamide)

Cas Number:

131-92-0

Molecular formula:

C42H23N3O6

IUPAC Name:

N,N'-(10,15,16,17-tetrahydro-5,10,15,17-tetraoxo-5H-dinaphtho[2,3-a:2',3'-i]carbazole-4,9-diyl)bis(benzamide)

Test material form:

solid: particulate/powder

Details on test material:

Vat Brown 3

Specific details on test material used for the study:

Reference no: Y01776/010/001

Method

Species / strain

Species / strain / cell type:

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

Metabolic activation:

with and without

Metabolic activation system:

Aroclor-induced rat liver S9

Test concentrations with justification for top dose:

4 to 2500 µg/plate
Limit of solubility: 2000 µg/plate

Vehicle / solvent:

Dimethylsulphoxide (DMSO)

Controls

Untreated negative controls:

yes

Negative solvent / vehicle controls:

yes

Remarks:

Dimethylsulphoxide (DMSO)

True negative controls:

no

Positive controls:

yes

Positive control substance:

9-aminoacridine

other: 2-Aminoanthracene, Daunorubicin, N-Methyl-N'-nitro-N-nitrosoguanidine

Details on test system and experimental conditions:

The Salmonella/microsome mutagenicity assay was conducted using the plate incorporation assay as described by Ames et al (1975), with certain modifications as specified in ETAD Toxicological Method No 005

The test compound was assayed once, over a dose range of 2500-4.0 µg/plate, with and without metabolic activation. If the test compound gave positive or inconclusive results in this initial assay were retested using the appropriate strains and metabolic activation conditions. Where appropriate, these repeat assays were performed over different dose ranges to allow a more detailed examination of the responses originally observed. Due to the precipitation of the test compound at high plate concentrations, samples which gave an unequivocal negative result in the initial assay were not retested at higher dose levels. The studies commenced on 11 August 1981 and were completed on 21 September 1981.

Evaluation criteria:

A positive response in the assay system was taken to be a two-fold or greater increase in the mean number of revertant colonies appearing in the test plates over and above the background spontaneous reversion rate observed with the solvent, together with evidence of a dose response at sub-toxic concentrations of the test substance. Observed positive responses were validated by replica plating (Elek and.Hilson, 1954). This technique verifies whether true reversion to prototrophy has occurred.

Results and discussion

Test results

Species / strain:

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

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity, but tested up to precipitating concentrations

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Additional information on results:

The test compound, together with appropriate positive and negative controls, was examined in at least two independent experiments both in the presence and absence of an auxiliary metabolising system (S9).

In each experiment, the positive controls responded as expected indicating that the assay was performing satisfactorily. Under the conditions of this assay, Substance H112339 gave a negative, ie non-mutagenic response in S-typhimurium strains TA1535, TA1537, TA98 and TA100 and in E.coli strains WP2P and WP2P uvrA in both the presence and absence of S9.

Applicant's summary and conclusion

Conclusions:

Under the conditions of this assay, the test substance gave a negative, is non-mutagenic, response with S-typhimurium strains TA1535, TA1537, TA98 and TA100 in the presence and absence of an auxiliary metabolising system (S9).

Executive summary:

When tested to the limit of solubility (2000 µg/plate), this compound gave a negative result in the absence of metabolic activation. In the presence of S9, a positive result was obtained in strain TA1537 at a single dose (500 µg/plate), with no dose-related response at lower plate concentrations. On retesting, this result was not repeatable, and would thus appear to be an artifact rather than a true positive result. The compound gave a negative result with the other three strains in the presence of S9.