Isocyanic acid, polymethylenepolyphenylene ester, 2-ethyl-1-hexanol-blocked

Genetic toxicity: in vitro

Administrative data

Endpoint:

in vitro gene mutation study in bacteria

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

OECD 471 "Bacterial Reverse Mutation Test" adopted 21st July 1997

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2007

Report date:

2007

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:

1-isocyanato-2-[(4-isocyanatophenyl)methyl]benzene; 1-isocyanato-4-[(4-isocyanatophenyl)methyl]benzene; 2-ethylhexyl N-(4-{[4-({[(2-ethylhexyl)oxy]carbonyl}amino)phenyl]methyl}phenyl)carbamate; 2-ethylhexyl N-{4-[(4-isocyanatophenyl)methyl]phenyl}carbamate

EC Number:

700-674-2

Cas Number:

147993-65-5

Molecular formula:

Unspecified Not applicable, since UVCB

IUPAC Name:

1-isocyanato-2-[(4-isocyanatophenyl)methyl]benzene; 1-isocyanato-4-[(4-isocyanatophenyl)methyl]benzene; 2-ethylhexyl N-(4-{[4-({[(2-ethylhexyl)oxy]carbonyl}amino)phenyl]methyl}phenyl)carbamate; 2-ethylhexyl N-{4-[(4-isocyanatophenyl)methyl]phenyl}carbamate

Test material form:

liquid

Specific details on test material used for the study:

Batch number: LL6-077

Method

Species / strain

Species / strain / cell type:

S. typhimurium, other: TA 98, TA 100, TA 102, TA 1535, TA 1537

Additional strain / cell type characteristics:

not applicable

Metabolic activation:

with and without

Metabolic activation system:

Aroclor 1254 induced male rat liver S9 mix

Test concentrations with justification for top dose:

First test: 0, 50, 158, 500, 1581, 5000 µg/plate (all TA strains, without and with S9 mix)
Repeat test: 0 - 5000 µg/tube (different concentrations for the 5 TA strains, without and with S9 mix)

Vehicle / solvent:

Solvents used: ethylene glycol dimethylether (EGDE) dried with a molecular sieve 0.3nm (test substance), deionized water (mitomycin C), DMSO (sodium azide, nitrofurantoin, 4-nitro-1,2-phenylene diamine, cumene hydroperoxide, 2-aminoanthracene)

Controls

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: sodium azide (only TA 1535), nitrofurantoin (only TA 100), 4-nitro-1,2-phenylene diamine (TA 1537 and TA 98), mitomycin C (only TA 102 in plate incorporation assay), cumene hydroperoxide (only TA 102 in preincubation assay), 2-aminoanthracene.

Remarks:

The positive controls sodium azide, nitrofurantoin, 4-nitro-1,2-phenylene diamine, mitomycin C and cumene hydroperoxide were only used without S9 mix; the positive control 2-aminoanthracene was only used with S9 mix.

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.

Statistics:

Not specified.

Results and discussion

Test results

Test results 1

Key result

Species / strain:

S. typhimurium TA 102

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Remarks:

precipitation at 500 µg/plate and higher

Vehicle controls validity:

valid

Untreated negative controls validity:

not examined

True negative controls validity:

not examined

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:

cytotoxicity

Remarks:

cytotoxic effects at doses up to and including 158 µg/plate and higher precipitation at 500 µg/plate and higher

Vehicle controls validity:

valid

Untreated negative controls validity:

not examined

True negative controls validity:

not examined

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:

cytotoxicity

Remarks:

cytotoxic effects at doses up to and including 5000 µg/plate precipitation at 500 µg/plate and higher

Vehicle controls validity:

valid

Untreated negative controls validity:

not examined

True negative controls validity:

not examined

Positive controls validity:

valid

Test results 4

Key result

Species / strain:

S. typhimurium TA 100

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Remarks:

cytotoxic effects at doses up to and including 158 µg/plate and higher precipitation at 500 µg/plate and higher

Vehicle controls validity:

valid

Untreated negative controls validity:

not examined

True negative controls validity:

not examined

Positive controls validity:

valid

Test results 5

Key result

Species / strain:

S. typhimurium TA 1535

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Remarks:

at 1581 µg/plate and higher precipitation at 500 µg/plate and higher

Vehicle controls validity:

valid

Untreated negative controls validity:

not examined

True negative controls validity:

not examined

Positive controls validity:

valid

Additional information on results:

Ames test:
- Signs of toxicity: yes
- Individual plate counts: yes
- Mean number of revertant colonies per plate and standard deviation: yes

Any other information on results incl. tables

Table 1: Summary of results from the Salmonella mutagenicity assay (first test) with Desmodur MT (mean values of revertants per plate)

Dose (µg per plate)	Without metabolic activation
	TA 1535	TA 100	TA 1537	TA 98	TA 102
Vehicle control (EGDE)	14	183	7	28	178
50	12	143	6	27	189
158	14	159	6	23	183
500	11	64	6	10	191
1581	9	45	5	8	185
5000	---	57	---	8	175
Positive control	579	415	76	126	511
Dose (µg per plate )	With metabolic activation (liver S9 mix)
	TA 1535	TA 100	TA 1537	TA 98	TA 102
Vehicle control (EGDE)	8	187	6	21	321
50	9	191	7	18	314
158	8	219	8	28	332
500	8	139	7	22	234
1581	7	138	7	24	213
5000	---	149	---	19	211
Positive control	130	1000	126	1114	440

--- = no value available

Table 2: Summary of results from the Salmonella mutagenicity assay (repeat test) with Desmodur MT (mean values of revertants per tube)

Dose (µg per tube)	Without metabolic activation
	TA 1535	TA 100	TA 1537	TA 98	TA 102
Vehicle control (EGDE)	22	151	7	33	274
5	28	134	n.t.	30	n.t.
16	29	148	7	33	n.t.
50	28	136	6	33	263
158	25	115	7	18	294
500	17	100	5	14	268
1581	n.t.	n.t.	6	n.t.	235
5000	n.t.	n.t.	n.t.	n.t.	246
Positive control	617	432	109	156	506
Dose (µg per tube )	With metabolic activation (liver S9 mix)
	TA 1535	TA 100	TA 1537	TA 98	TA 102
Vehicle control (EGDE)	15	210	8	34	252
16	11	213	7	n.t.	n.t.
50	11	193	8	40	269
158	10	200	10	43	316
500	10	183	8	47	348
1581	12	163	8	45	340
5000	n.t.	n.t.	n.t.	38	327
Positive control	140	1372	135	885	467

n.t. = not tested

Doses up to and including 50 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 strain-specific bacteriotoxic effect. Substance precipitation occurred at the dose 500 µg per plate and above. Due to these effects this range could only partly be used up to 5000 µg per plate for assessment purposes.

Evidence of mutagenic activity of Desmodur MT was not seen. No biologically relevant increase in the mutant count, in comparison with the negative controls, was observed.

The positive controls sodium azide, nitrofurantoin, 4-nitro-1,2-phenylene diamine, mitomycin C, cumene hydroperoxide and 2-aminoanthracene had a marked mutagenic effect, as was seen by a biologically relevant increase in mutant colonies compared to the corresponding negative controls.

Applicant's summary and conclusion

Conclusions:

negative

Executive summary:

In an Ames test with the S. typhimurium strains TA 98, TA 100, TA 102, TA 1535, and TA 1537 Desmodur MT revealed no mutagenic activity in the absence and in the presence of a metabolic activation system (OECD TG 471).