A mixture of: 3,3'-dicyclohexyl-1,1'-methylenebis(4,1-phenylene)diurea; 3-cyclohexyl-1-(4-(4-(3-octadecylureido)benzyl)phenyl)urea; 3,3'-dioctadecyl-1,1'-methylenebis(4,1-phenylene)diurea

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:

28 April, 2006 - 08 May, 2006

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2006

Report date:

2006

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Version / remarks:

(1997)

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

(2000)

Deviations:

no

GLP compliance:

yes

Type of assay:

bacterial reverse mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

1‐cyclohexyl‐3‐[4‐({4‐[(octadecylcarbamoyl)amino]phenyl}methyl)phenyl]urea

EC Number:

604-940-8

Cas Number:

154099-21-5

Molecular formula:

C39 H62 N4 O2

IUPAC Name:

1‐cyclohexyl‐3‐[4‐({4‐[(octadecylcarbamoyl)amino]phenyl}methyl)phenyl]urea

Constituent 2

Reference substance name:

3,3'-dicyclohexyl-1,1'-methylenebis(4,1-phenylene)diurea

EC Number:

406-370-3

EC Name:

3,3'-dicyclohexyl-1,1'-methylenebis(4,1-phenylene)diurea

Cas Number:

58890-25-8

Molecular formula:

C27 H36 N4 O2

IUPAC Name:

3‐cyclohexyl‐1‐[4‐({4‐[(cyclohexylcarbamoyl)amino]phenyl}methyl)phenyl]urea

Constituent 3

Reference substance name:

3,3'-dioctadecyl-1,1'-methylenebis(4,1-phenylene)diurea

EC Number:

406-690-3

EC Name:

3,3'-dioctadecyl-1,1'-methylenebis(4,1-phenylene)diurea

Cas Number:

43136-14-7

Molecular formula:

C51 H88 N4 O2

IUPAC Name:

3‐octadecyl‐1‐[4‐({4‐[(octadecylcarbamoyl)amino]phenyl}methyl)phenyl]urea

Test material form:

solid: particulate/powder

Details on test material:

- Name of test material (as cited in study report): MDI/CHA/ODA
- Description: White powder

The data on the individual constituents CHA/MDI/CHA (EC 406-370-3) and ODA/MDI/ODA (EC 406-690-3) for physicochemical, environmental fate, ecotoxicological and mammalian toxicological endpoints are very similar to the data available for the different compositions of the multi-constituent or represent the outer boundaries of the data on the multi-constituent. Hence, they confirm that the different compositions are expected to have similar properties for physicochemical, environmental fate, ecotoxicological and mammalian toxicological endpoints.

Method

Target gene:

- S. typhimurium: Histidine gene
- E. coli: Tryptophan gene

Species / strain

Species / strain 1

Species / strain / cell type:

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

Species / strain 2

Species / strain / cell type:

E. coli WP2 uvr A

Metabolic activation:

with and without

Metabolic activation system:

Rat liver S9-mix induced by a combination of phenobarbital and ß-naphthoflavone

Test concentrations with justification for top dose:

Experiment 1
Preliminary test (without and with S9) TA100 and WP2uvrA: 3, 10, 33, 100, 333, 1000, 3330 and 5000 µg/plate
Main study: TA1535, TA1537 and TA98:
Without and with S9-mix: 1, 3, 10, 33 and 100 µg/plate
Experiment 2: all strains
Without and with S9-mix: 1, 3, 10, 33 and 100 µg/plate

Vehicle / solvent:

- Vehicle(s)/solvent(s) used: Ethanol
- Justification for choice of solvent/vehicle: A homogeneous suspension could be obtained in ethanol and ethanol is accepted and approved by authorities and international guidelines.

Controls

Controls 1

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

Positive controls:

yes

Positive control substance:

methylmethanesulfonate

Remarks:

without S9: 650 µg/plate in DMSO for TA100

Controls 2

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

Positive controls:

yes

Positive control substance:

other: 2-nitrofluorene 10 µg/plate in DMSO for TA98

Remarks:

without S9

Controls 3

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

Positive controls:

yes

Positive control substance:

other: 9-aminoacridine 60 µg/plate in DMSO for TA1537

Remarks:

without S9

Controls 4

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

Positive controls:

yes

Positive control substance:

4-nitroquinoline-N-oxide

Remarks:

without S9: 10 µg/plate in DMSO for WP2uvrA

Controls 5

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

Positive controls:

yes

Positive control substance:

sodium azide

Remarks:

without S9: 5 µg/plate in saline for TA1535

Controls 6

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

Positive controls:

yes

Positive control substance:

other: 2-aminoanthracene in DMSO for all tester strains

Remarks:

with S9

Details on test system and experimental conditions:

METHOD OF APPLICATION: in agar (plate incorporation)

DURATION
- Exposure duration: 48 hour

NUMBER OF REPLICATIONS:
- Doses of the test substance were tested in triplicate in each strain. Two independent experiments were conducted.

NUMBER OF CELLS EVALUATED: 10E8 per plate

DETERMINATION OF CYTOTOXICITY
- Method: The reduction of the bacterial background lawn, the increase in the size of the microcolonies and the reduction of the revertant colonies.

OTHER EXAMINATIONS:
- The presence of precipitation of the test compound on the plates was determined.

Evaluation criteria:

A test substance is considered negative (not mutagenic) in the test if:
a) The total number of revertants in tester strain TA100 is not greater than two (2) times the concurrent control, and the total number of revertants in tester strains TA1535, TA1537, TA98 or WP2uvrA is not greater than three (3) times the concurrent control.
b) The negative response should be reproducible in at least one independently repeated experiment.

A test substance is considered positive if:
a) The total number of revertants in tester strain TA 100 is greater than two (2) times the concurrent control, or the total number of revertants in tester strain TA 1535, TA 1537, TA98 or WP2uvrA is greater than three (3) times the concurrent control.
b) In case a positive response will be repeated, the positive response should be reproducible in at least one independently repeated experiment.

Results and discussion

Test results

Test results 1

Key result

Species / strain:

S. typhimurium 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

Positive controls validity:

valid

Test results 2

Key result

Species / strain:

S. typhimurium TA 98

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity, but tested up to precipitating concentrations

Vehicle controls validity:

valid

Positive controls validity:

valid

Test results 3

Key result

Species / strain:

S. typhimurium TA 1537

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity, but tested up to precipitating concentrations

Vehicle controls validity:

valid

Positive controls validity:

valid

Test results 4

Key result

Species / strain:

S. typhimurium TA 1535

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity, but tested up to precipitating concentrations

Vehicle controls validity:

valid

Positive controls validity:

valid

Test results 5

Key result

Species / strain:

E. coli WP2 uvr A

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity, but tested up to precipitating concentrations

Vehicle controls validity:

valid

Positive controls validity:

valid

Additional information on results:

TEST-SPECIFIC CONFOUNDING FACTORS
- Precipitation: Precipitation was observed at dose levels of 100 µg/plate and upwards.

RANGE-FINDING/SCREENING STUDIES:
- No toxicity or mutagenicity was observed up to and including the top dose of 5000 µg/plate

COMPARISON WITH HISTORICAL CONTROL DATA:
- The negative and strain-specific positive control values were within the laboratory historical control data ranges indicating that the test conditions were adequate and that the metabolic activation system functioned properly.

ADDITIONAL INFORMATION ON CYTOTOXICITY:
- No toxicity or mutagenicity was observed up to and including the top dose of 100 µg/plate

Applicant's summary and conclusion

Conclusions:

Interpretation of results: negative

The substance is not mutagenic in the Salmonella typhimurium reverse mutation assay and in the Escherichia coli reverse mutation assay, performed according to OECD 471 guideline and GLP principles.

Executive summary:

The genetic toxicity of MDI/CHA/ODA was assessed using Salmonella typhimurium TA98, TA100, TA1535 and TA1537 strains, and Escherichia coli WP2uvrA strain, in accordance with OECD 471 guideline and GLP principles. Precipitation was observed at the top dose of 100 µg/plate. No toxicity was observed in all strains.

All bacterial strains showed negative responses over the entire dose range, i.e. no biologically significant dose-related increase in the number of revertants in two independently repeated experiments with and without metabolic activation up to the highest concentration of 100 µg/plate. Based on the results it is concluded that the substance is not mutagenic in the Salmonella typhimurium reverse mutation assay and in the Escherichia coli reverse mutation assay.