TDI Biuret

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:

2010

Report date:

2010

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)

Remarks:

deviation: no analytical data on chemical composition of the test item were submitted by the sponsor; however, this deviation did not limit the assessment of the results.

Type of assay:

bacterial reverse mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

Reaction product of 2,4/ 2,6 TDI (m-tolylidene diisocyanate, CAS 26471-62-5) in excess and m-TDA (diaminotoluene, CAS 25376-45-8) forming Biuret structures via non-isolated polyurea intermediates

IUPAC Name:

Reaction product of 2,4/ 2,6 TDI (m-tolylidene diisocyanate, CAS 26471-62-5) in excess and m-TDA (diaminotoluene, CAS 25376-45-8) forming Biuret structures via non-isolated polyurea intermediates

Details on test material:

- Name of test material (as cited in study report): Desmodur VP.PU 60WF14
- Physical state: liquid
- Purity: 100 % (as indicated by the sponsor)
- Lot/batch No.: P1DE000345
- Storage condition of test material: room temperature

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 (without and with S9 mix)
Repeat test: 0, 60, 120, 240, 480, 960, 1920 µg/plate (only TA 98, TA 102 and TA 1537, only 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), 2-aminoanthracene.

Remarks:

The positive controls sodium azide, nitrofurantoin, 4-nitro-1,2-phenylene diamine and mitomycin C 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

Species / strain:

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

Metabolic activation:

with

Genotoxicity:

positive

Cytotoxicity / choice of top concentrations:

other: strain-specific bacteriotoxic effect at 1581 and 5000 µg/plate

Vehicle controls validity:

valid

Untreated negative controls validity:

not examined

Positive controls validity:

valid

Test results 2

Species / strain:

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

Metabolic activation:

with

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

other: strain-specific bacteriotoxic effect at 1581 and 5000 µg/plate

Vehicle controls validity:

valid

Untreated negative controls validity:

not examined

Positive controls validity:

valid

Test results 3

Species / strain:

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

Metabolic activation:

without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

other: strain-specific bacteriotoxic effect at 1581 and 5000 µg/plate

Vehicle controls validity:

valid

Untreated negative controls validity:

not examined

Positive controls validity:

valid

Remarks on result:

other: strain/cell type: TA 98, TA 102, TA 1537

Remarks:

Migrated from field 'Test system'.

Any other information on results incl. tables

Table 1: Summary of results from the Salmonella mutagenicity assay (first test) with Desmodur VP.PU 60WF14 (mean values of revertants per plate)

Dose (µg per plate)	Without metabolic activation
	TA 1535	TA 100	TA 1537	TA 98	TA 102
Solvent EGDE	8	116	6	14	250
50	7	95	6	14	189
158	9	83	6	9	172
500	7	108	4	13	143
1581	3	33	5	16	184
5000	3	37	0	9	157
Positive control	1259	358	42	91	1482
Dose ( µg per plate )	With metabolic activation (liver S9 mix)
	TA 1535	TA 100	TA 1537	TA 98	TA 102
Solvent EGDE	9	182	8	24	316
50	7	187	9	30	325
158	10	239	13	51	249
500	8	242	23	115	411
1581	7	160	20	98	350
5000	2	72	0	38	234
Positive control	157	2415	134	2364	675

Table 2: Summary of results from the Salmonella mutagenicity assay (repeat test) with Desmodur VP.PU 60WF14 (mean values of revertants per plate)

Dose ( µg per plate )	With metabolic activation (liver S9 mix)
	TA 1535	TA 100	TA 1537	TA 98	TA 102
Solvent EGDE	---	---	7	36	341
60	---	---	16	92	289
120	---	---	14	128	295
240	---	---	20	185	411
480	---	---	26	236	462
960	---	---	21	257	450
1920	---	---	21	160	356
Positive control	---	---	103	2640	936

Doses up to and including 960 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, so that this range could only be used up to and including 1920 µg per plate for assessment purposes. Substance precipitation occurred at the dose 960 µg per plate and above.

Evidence of mutagenic activity of Desmodur VP.PU 60WF14 was seen. On Salmonella typhimurium strains TA 1537, TA 98 and TA 102, a biologically relevant increase was found in the mutant count compared to the corresponding negative control. Positive response was found only with S9 mix. The lowest reproducible effective dose was 158 µg per plate for TA 98 and 500 µg per plate for TA 1537 and TA 102. The Salmonella/microsome test thus showed Desmodur VP.PU 60WF14 to have a mutagenic effect.

The positive controls sodium azide, nitrofurantoin, 4-nitro-1,2-phenylene diamine, mitomycin C 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:

Interpretation of results (migrated information):
positive with metabolic activation

Executive summary:

In an Ames test according to OECD TG 471 evidence of mutagenic activity of Desmodur VP.PU 60WF14 was seen. On Salmonella typhimurium strains TA 98, TA 102 and TA 1537 a biologically relevant increase was found in the mutant count compared to the corresponding negative control. Positive response was found only with S9 mix. In the absence of a metabolic activation system no mutagenic activity was found with the strains TA 98, TA 100, TA 102, TA 1535 and TA 1537. Based on these results, Desmodur

VP.PU 60WF14 is considered to be mutagenic in the Ames test with metabolic activation.