HDI oligomers, uretdione

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

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2006

Report date:

2006

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Version / remarks:

(1997)

GLP compliance:

yes (incl. QA statement)

Type of assay:

bacterial reverse mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

N-[6-(3-{6-[3-(6-formamidohexyl)-2,4-dioxo-1,3-diazetidin-1-yl]hexyl}-2,4-dioxo-1,3-diazetidin-1-yl)hexyl]formamide; N-{6-[3-(6-formamidohexyl)-2,4-dioxo-1,3-diazetidin-1-yl]hexyl}formamide

EC Number:

931-288-4

Molecular formula:

(C8H12N2O2)n

IUPAC Name:

N-[6-(3-{6-[3-(6-formamidohexyl)-2,4-dioxo-1,3-diazetidin-1-yl]hexyl}-2,4-dioxo-1,3-diazetidin-1-yl)hexyl]formamide; N-{6-[3-(6-formamidohexyl)-2,4-dioxo-1,3-diazetidin-1-yl]hexyl}formamide

Constituent 2

Reference substance name:

28182-81-2

Cas Number:

28182-81-2

IUPAC Name:

28182-81-2

Details on test material:

- Stability under test conditions: A stability test in the solvent, did not reveal significant degradation of the active ingredient.

Method

Target gene:

histidine locus

Species / strain

Species / strain / cell type:

S. typhimurium TA 1535, TA 1537, TA 98, TA 100 and TA 102

Metabolic activation:

with and without

Metabolic activation system:

S9 Mix from rat liver homogenates with Aroclor 1254 for enzyme induction

Test concentrations with justification for top dose:

initial testing (plate incorporation; with and without S9 mix): 50-5000 µg/plate
mutation test 1 (plate incorporation; with and without S9 mix): 0.05-50.0 µg/plate for TA 1535, TA 100, TA 1537, and TA 98; 0.05-158.0 µg/plate for TA 102
mutation test 2 (preincubation, with and without S9 mix): 0.05-50.0 µg/tube for TA 1535, TA 100, TA 1537, and TA 98; 0.05-158.0 µg/tube for TA 102

Vehicle / solvent:

DMSO (dried with molecular sieve, 0.3 nm)

Controls

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

Remarks:

DMSO

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: Na-azide (NaN3, only TA 1535), nitrofurantoin (NF, only TA 100), 4-nitro-1,2-phenylene diamine (4-NPDA, TA 1537 and TA 98), mitomycin C (MMC, only TA 102), cumene hydroperoxide (Cumene, only TA 102), 2-aminoanthracene (2-AA, all strains)

Remarks:

The positive controls NaN3, NF, 4-NPDA, MMC, and Cumene were only used without S9 mix; the positive control 2-AA was used with S9 mix.

Details on test system and experimental conditions:

METHOD OF APPLICATION: in agar for dose selection (50-5000 µg/plate, with and without S9 mix); in agar (plate incorporation) for initial testing (0.05-50.0 µg/plate, with and without S9 mix); as preincubation testing for independent repeat (0.05-50.0 µg/tube, with and without S9 mix; preincubation for 20 min. at 37°C).
Testings for each strain and dose was performed in triplicate, which is also valid for solvent and positive controls.

DETERMINATION OF CYTOTOXICITY
- background growth
- mutant count: A toxic effect was assumed when there was a marked and dose-dependent reduction in the mutant count per plate, compared to the negative controls.

Evaluation criteria:

A reproducible and dose-related increase in mutant counts of at least one strain is considered to be a positive result. For TA 1535, TA 100 and TA 98 this increase should be about twice that of negative controls, whereas for TA 1537, at least a threefold increase should be reached. For TA 102 an increase of about 100 mutants should be reached. Otherwise, the result is evaluated as negative. However, these guidelines may be overruled by good scientific judgment.
In case of questionable results, investigations should continue, possibly with modifications, until a final evaluation is possible.

Results and discussion

Test results

Species / strain:

S. typhimurium TA 1535, TA 1537, TA 98, TA 100 and TA 102

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

not applicable

Positive controls validity:

valid

Additional information on results:

Evidence of mutagenic activity of Desmodur N 3400 was not seen. No biologically relevant increase in the mutant count, in comparison with the negative controls, was observed.
The positive controls had a marked mutagenic effect, as was seen by a biologically relevant increase in mutant colonies compared to the corresponding negative controls.

ADDITIONAL INFORMATION ON CYTOTOXICITY: Doses up to and including 1.6 µg per plate did not cause any bacteriotoxic effects. Total bacteria counts remained unchanged and no inhibition of growth was observed. At higher doses, the substance had a strong, strain-specific bacteriotoxic effect, so that this range could only be used to a limited extent up to and including 50 µg per plate for assessment purposes.

Remarks on result:

other: all strains/cell types tested

Remarks:

Migrated from field 'Test system'.

Applicant's summary and conclusion

Executive summary:

A bacterial reverse mutation assay (Ames) according to OECD TG 471 was conducted for the evaluation of point mutagenic effects. In this assay 5 strains of Salmonella typhimurium were used (TA 1535, TA 100, TA 1537, TA 98, and TA 102) and the assay was conducted with and without S9 mix. The test substance was investigated in a plate incorporation test in doses up to 5000 µg/plate. The independent repeat was performed as preincubation modification (20 minutes at 37 °C) using doses up 158 µg/tube.

Doses up to and including 1.6 µg per plate did not cause any bacteriotoxic effects. Total bacteria counts remained unchanged and no inhibition of growth was observed. At higher doses, the substance had a strong, strain-specific bacteriotoxic effect, so that this range could only be used to a limited extent up to and including 50 µg/plate for assessment purposes. No biologically relevant increase in the mutant count in comparison with the negative controls was observed, therefore, the test substance was considered to be non-mutagenic in the plate incorporation as well as in the preincubation modification of the Ames test.