5-amino-2,4,6-triiodoisophthalic acid

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:

May 1991

Reliability:

1 (reliable without restriction)

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1991

Report date:

1991

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method B.13/14 (Mutagenicity - Reverse Mutation Test Using Bacteria)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Type of assay:

bacterial reverse mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

5-amino-2,4,6-triiodoisophthalic acid

EC Number:

252-575-4

EC Name:

5-amino-2,4,6-triiodoisophthalic acid

Cas Number:

35453-19-1

Molecular formula:

C8H4I3NO4

IUPAC Name:

5-amino-2,4,6-triiodobenzene-1,3-dicarboxylic acid

Details on test material:

The solution of the test substance was prepared fresh daily in DMSO or in sterile distilled water for the range-finding test, the subsequent diluitions were prepared.
The S9 mix and the solution of the test substance were controlled for sterility. Both were spread on a nutrient agar and no colonies were observed.

Method

Target gene:

Histidine operon mutation

Species / strain

Species / strain / cell type:

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

Metabolic activation:

with

Metabolic activation system:

histidine operon mutation

Test concentrations with justification for top dose:

The appropriate dilutions of the test substance were made from a 51.2 mg/ml stock solution.
The test substance was tested at five dose levels of 20, 80, 320, 1280 and 5120 μg per Petri dish.
Every concentration was tested in triplicate.

Vehicle / solvent:

DMSO

Controls

Controls 1

Positive controls:

yes

Positive control substance:

N-ethyl-N-nitro-N-nitrosoguanidine

Controls 2

Positive controls:

yes

Positive control substance:

9-aminoacridine

Controls 3

Positive controls:

yes

Positive control substance:

other: 4-nitro-O-phenylenediamine

Controls 4

Positive controls:

yes

Positive control substance:

other: duanomycine

Details on test system and experimental conditions:

The toxicity of the test substance was evaluated in a preliminary test to fix the highest dose to be evaluated in the main test.

A quantitative test was performed as described below only with the strain TA98, in the presence and absence of S9 mix, at three concentrations: 51.2, 512 and 5120 µg per Petri dish. The test were made in duplicate. As no toxicity was shown at 5120 µg per Petri dish, the standard concentration of 20, 80, 320, 1280 and 5120 µg were chosen for the main test.

The test system was as follows; the under mentioned compounds were added to sterile glass tubes in the given order:
- 0.1 ml of solution of test substance to be tested
- 0.5 ml of S9 mix (or 0.85 % NaCl for testing in absence of S9)
- 0.1 ml of bacterial suspension (2-3 x 10^8 bacteria)
- 2 ml of molten top agar at 45°C.

The top agar was a 0.6 % Bacto-Difco agar, 0.5 % NaCl solution. Before use, agar was melted in a boiling water bath and then left to cool to 45°C. 10 ml of sterile 0.5 mM L-histidine - 0.5 mM biotin were added per 100 ml of top agar.

The tubes were agitated using a vortex mixer and poured onto the minimal medium base. The plates were incubated for 48 hours at 37°C in the dark. The colonies, i.e. the revertants to the wild type, were counted manually or electronically using a Fisher Colony Counter. Each strain has a characteristic spontaneous reversion rate.

An examination under the microscope was used to verify the presence of the background produced by growth of auxotrophic bacteria on traces of histidine and biotin, or the absence of this background due to a toxic effect of the test substance.

Evaluation criteria:

The criteria of mutagenicity used in this test are a doubling of the spontaneous reversion rate accompanied by a dose-effect relationship.

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:

other: The test substance is toxic for the bacteria in absence of S9 at the highest dose (5120 µg per plate) with strain TA1537.

Remarks on result:

other: all strains/cell types tested

Remarks:

Migrated from field 'Test system'.

Applicant's summary and conclusion

Conclusions:

Interpretation of results (migrated information):
negative

According to the criteria of mutagenicity, the test substance in not mutagenic for the five strains of Salmonella typhimurium used in this test both in presence or in absence os a metabolic activation with Aroclor 1254-induced rat liver microsomes.