1,3-bis(1-isocyanato-1-methylethyl)benzene

Genetic toxicity: in vitro

Administrative data

Endpoint:

in vitro gene mutation study in bacteria

Type of information:

experimental study

Adequacy of study:

key study

Study period:

From Feb. 10, 1986 to Feb. 14, 1986

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1986

Report date:

1986

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Deviations:

yes

Remarks:

No additional analyses of the composition and stability of the test sample in the solvent or test system were performed

GLP compliance:

yes

Type of assay:

bacterial reverse mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

1,3-bis(1-isocyanato-1-methylethyl)benzene

EC Number:

220-474-4

EC Name:

1,3-bis(1-isocyanato-1-methylethyl)benzene

Cas Number:

2778-42-9

Molecular formula:

C14H16N2O2

IUPAC Name:

1,3-bis(1-isocyanato-1-methylethyl)benzene

Test material form:

liquid: viscous

Details on test material:

- Name of test material (as cited in study report): m-Tetramethylxylene Diisocyanate (m-TMXDI)
- Physical state: Clear, non-viscous liquid
- Analytical purity: 98 %
- Density: 1.05 g/mL
- Storage condition of test material: Stored under nitrogen at room temperature

Method

Target gene:

Not applicable

Species / strain

Species / strain 1

Species / strain / cell type:

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

Details on mammalian cell type (if applicable):

not applicable

Additional strain / cell type characteristics:

not applicable

Species / strain 2

Species / strain / cell type:

S. typhimurium TA 1538

Details on mammalian cell type (if applicable):

not applicable

Additional strain / cell type characteristics:

not applicable

Metabolic activation:

with and without

Metabolic activation system:

Aroclor-1254 induced, rat-liver homogenate (S9

Test concentrations with justification for top dose:

Preliminary Toxicity study: 0.001, 0.003, 0.01, 0.03, 1, 3, 5 and 10 mg/plate
Definitive study: 0.0003, 0.001, 0.003, 0.01 and 0.03 mg/plate

Vehicle / solvent:

- Vehicle(s)/solvent(s) used: Acetone
- Justification for choice of solvent/vehicle: Test material was soluble in acetone

Controls

Untreated negative controls:

yes

Remarks:

Acetone

Negative solvent / vehicle controls:

yes

Remarks:

Acetone

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: 4-nitro-o-phenylenediamine, 9-aminoacridine, sodium azide and 2-aminoanthracene

Remarks:

with and without metabolic activation

Details on test system and experimental conditions:

METHOD OF APPLICATION: in agar (plate incorporation)


DURATION
- Expression time: 48-72 h


NUMBER OF REPLICATIONS: Three


DETERMINATION OF CYTOTOXICITY
- Method: Growth inhibition of the background lawn or a reduction in the number of spontaneous mutants

Evaluation criteria:

If the mean number of revertant colonies was not increased to two or three times higher than the concurrent solvent control value, then the test chemical was not considered to be a bacterial mutagen.

Statistics:

No data

Results and discussion

Test results

Test results 1

Key result

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

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Test results 2

Key result

Species / strain:

S. typhimurium TA 1538

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

Additional information on results:

RANGE-FINDING/SCREENING STUDIES: Test chemical at concentration range of 0.001-10 mg/plate was evaluated for cytotoxicity using strain TA100. Toxicity assessed at 24-48 h by observations for either growth inhibition of the backgroud lawn or a reduction in the number of spontaneous mutants.


COMPARISON WITH HISTORICAL CONTROL DATA: Yes


ADDITIONAL INFORMATION ON CYTOTOXICITY:
Cytotoxicity in the definitive test was defined as either a reduction in the number of revertant colonies or an inhibition of growth of the background lawn.
- In the test without metabolic activation, dose-related toxicity was observed in all strains except TA1535 at 0.03 mg /plate.
- In the test with metabolic activation, some degree of toxicity was observed at 0.03 mg/plate with all strains except TA98 and TA1535.

Remarks on result:

other: all strains/cell types tested

Remarks:

Migrated from field 'Test system'.

Any other information on results incl. tables

Preliminary study: Test material at concentration of 0.03 mg/plate allowed only sparse growth of the background lawn while a slightly higher dose of 0.1 mg/plate and higher dose levels produced complete absence of the background lawn and were considered to be cytotoxic.

Applicant's summary and conclusion

Conclusions:

Under the test conditions, the test material was considered to be non-mutagenic in the Salmonella/microsome bacterial mutagenicity assay.

Executive summary:

A study was conducted to evaluate the potential mutagenic activity of the test substance using the Salmonella/microsome bacterial mutagenicity assay (Ames test). The study was conducted according to OECD Guideline 471, in compliance with GLP. Test doses were chosen from the data obtained in a preliminary study which indicated that a concentration of 0.03 mg/plate allowed only sparse growth of the background lawn while 0.1 mg/plate and higher dose levels produced complete absence of the background lawn and were considered to be cytotoxic. The test substance was studied with and without metabolic activation using triplicate cultures at concentration range of 0.03-0.0003 mg/plate. Mutagenic activity was not observed with any of the five bacterial strains (S. typhimurium TA 1538, 1535, TA 1537, TA 98 and TA 100) with or without metabolic activation. Under the test conditions, the test substance was considered to be non-mutagenic in the Salmonella/microsome bacterial mutagenicity assay (Guzzie and Morabit, 1986).