HDI oligomers, oxadiazintrione

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:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Comparable to guideline study with acceptable restrictions: only 4 strains tested

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1986

Report date:

1986

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Deviations:

yes

Remarks:

, no E.coli WP2 or S. typhimurium TA 102 tested

GLP compliance:

not specified

Type of assay:

bacterial reverse mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

HDI oligomers, oxadiazintrione

IUPAC Name:

HDI oligomers, oxadiazintrione

Method

Target gene:

histidine locus

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:

S9 Mix from liver homogenates of Aroclor 1254 induced male rats

Test concentrations with justification for top dose:

initial testing (plate incorporation; with and without S9 mix): 19.2-12000 µg/plate
repeat (plate incorporation; with and without S9 mix): 19-9600 µg/plate;

Vehicle / solvent:

DMSO

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), 2-aminoanthracene (2-AA, all strains)

Remarks:

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

Details on test system and experimental conditions:

Strains were obtained from Prof. B. Ames in 1982 and maintained properly.

METHOD OF APPLICATION: According to Ames et al. (Proc. nat. Acad. Sci. 70, 2281-2285, 1973; Mutation Res. 31, 347-364, 1975).
Plate incorporation for initial testing and independent repeat; for each strain and dose four plates were used in parallel, which was also valid for solvent and positive controls.

DETERMINATION OF CYTOTOXICITY
- 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. This increase should be about twice that of negative controls.

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:

cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

not applicable

Positive controls validity:

valid

Additional information on results:

Evidence of mutagenic activity was not found. Neither a dose-related doubling of the mutant count nor a biologically relevant increase in the same, 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.

TEST-SPECIFIC CONFOUNDING FACTORS
- Precipitation: Substance precipitation occurred at and above 1200 µg/plate.

ADDITIONAL INFORMATION ON CYTOTOXICITY:
Doses up to and including 19.2 µg/plate did not cause any bacteriotoxic effects. The total bacteria counts remained unchanged. 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 very limited extent up to 12000 µg/plate for evaluation 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 according to the protocol of Ames et al. (Proc. nat. Acad. Sci. 70, 2281-2285, 1973; Mutation Res. 31, 347-364, 1975) was conducted for the evaluation of point mutagenic effects. In this assay 4 strains of Salmonella typhimurium were used (TA 1535, TA 100, TA 1537, and TA 98). The initial plate incorporation test used test substance doses of 19.2-12000 µg/plate. Due to bacteriotoxic effects doses for independent repeat were lowered to a maximum of 9600 µg/plate.

Substance precipitation occurred at and above 1200 µg/plate. Doses up to and including 19.2 µg/plate did not cause any bacteriotoxic effect. The total bacteria counts remained unchanged and thus 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 very limited extent for evaluation purposes.

Evidence of mutagenic activity was not found. Neither a dose-related doubling of the mutant count nor a biologically relevant increase in the same, 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.