Hexamethylene diisocyanate, oligomers, reaction products with Bis-(Trimethoxysilylpropyl)amine

Skin irritation / corrosion

Administrative data

Endpoint:

skin irritation: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2018

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2018

Report date:

2018

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 439 (In Vitro Skin Irritation: Reconstructed Human Epidermis Test Method)

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

1-{6-[3,5-bis(6-isocyanatohexyl)-2,4,6-trioxo-1,3,5-triazinan-1-yl]hexyl}-3,3-bis[3-(trimethoxysilyl)propyl]urea

EC Number:

918-105-3

IUPAC Name:

1-{6-[3,5-bis(6-isocyanatohexyl)-2,4,6-trioxo-1,3,5-triazinan-1-yl]hexyl}-3,3-bis[3-(trimethoxysilyl)propyl]urea

Test material form:

liquid: viscous

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Source and lot/batch No.of test material: 17/0241-1, Batch 294-296

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: The stability under storage conditions over the study period was guaranteed.
- Stability under test conditions: room temperature

In vitro test system

Test system:

human skin model

Source species:

human

Cell type:

non-transformed keratinocytes

Cell source:

foreskin from a single donor

Source strain:

not specified

Details on animal used as source of test system:

- Tissue model: EPI-200
- Tissue Lot Number: 25844
- Origin: MatTek In Vitro Life Science Laboratories, Bratislava, Slovakia

Justification for test system used:

The test system is part of an integrated approach on testing and assessment (IATA) for skin corrosion and irritation and is one of the accepted guideline studies.

Vehicle:

unchanged (no vehicle)

Details on test system:

RECONSTRUCTED HUMAN EPIDERMIS (RHE) TISSUE
- Model used: EpiDerm model
- Tissue batch number(s): 25844

TEMPERATURE USED FOR TEST SYSTEM
- Temperature used during treatment / exposure: 37°C
- Temperature of post-treatment incubation (if applicable): 37°C

NUMBER OF REPLICATE TISSUES: 3

PREDICTION MODEL / DECISION CRITERIA (choose relevant statement)
- The test substance is considered to be irritant if the viability is less than 45% compared to negative control.
- The test substance is considered to be non-irritant if the viability is higher than 55% compared to control.
- The test substance is considered to be corrosive to skin if the viability after 3 minutes exposure is less than 45%, or if the viability after 3 minutes exposure is greater than or equal to 45 % and the viability after 1 hour exposure is less than 10%.
- The test substance is considered to be non-corrosive to skin if the viability after 3 minutes exposure is greater than 55% and the viability after 1 hour exposure is greater than 20%.
- The borderline evaluation was determined statistically using historic data and hence considers the variance of the test method.This evaluation is an amendment to the evaluation provided in OECD Guideline 431.

Amount/concentration applied:

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 30 µl undiluted liquid test substance

NEGATIVE CONTROL
- PBS, sterile

POSITIVE CONTROL
- 5% (w/v) sodium dodecyl sulfate (SDS) in water

Duration of treatment / exposure:

1h

Duration of post-treatment incubation (if applicable):

32 - 36 h

Number of replicates:

3

Results and discussion

In vitro

Results

Results 1

Irritation / corrosion parameter:

% tissue viability

Run / experiment:

Tissue 1

Value:

76.1

Negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

no indication of irritation

Results 2

Irritation / corrosion parameter:

% tissue viability

Run / experiment:

Tissue 2

Value:

79

Negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

no indication of irritation

Results 3

Irritation / corrosion parameter:

% tissue viability

Run / experiment:

Tissue 3

Value:

66

Negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

no indication of irritation

Any other information on results incl. tables

Individual and mean OD570 values, individual and mean viability values and standard deviations

Test substance		Tissue 1	Tissue 2	Tissue 3	Mean	SD
NC	Mean OD570	1.370	1.417	1.298	1.362
NC	Viability (% of NC)	100.6	104.1	95.3	100.0	4.4
Test substance	Mean OD570	1.037	1.076	0.899	1.004
Test substance	Viability (% of NC)	76.1	79.0	66.0	73.7	6.8
PC	Mean OD570	0.046	0.054	0.049	0.050
PC	Viability (% of NC)	3.4	3.9	3.6	3.7	0.3

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Conclusions:

Based on the results observed and by applying the evaluation criteria, it was concluded that the test item does not show a skin irritation potential in the EpiDerm™ in vitro skin irritation and corrosion test strategy under the test conditions chosen.

Executive summary:

The objective was to assess the skin irritation and corrosion potential of the test item. Using the methods currently available, a single in vitro assay is not sufficient to cover the full range of skin irritating/corrosion potential. Therefore, two in vitro assays were part of this in vitro skin irritation and corrosion test strategy: The Skin Corrosion Test (SCT) and Skin Irritation Test (SIT).

However, in the current case the results derived with SIT alone were sufficient for a final assessment. Therefore, further testing in SCT was waived.

The potential of the test substance to cause dermal irritation was assessed by a single topical application of 30 μL of the undiluted test substance to a reconstructed three-dimensional human epidermis model (EpiDerm™). The irritation test was performed with three EpiDerm™ tissues, which were incubated with the test substance for 1 hour followed by a 42-hour post-incubation period.

Tissue destruction was determined by measuring the metabolic activity of the tissue after exposure/post-incubation by using a colorimetric test. The reduction of mitochondrial dehydrogenase activity measured by reduced formazan production after incubation with a tetrazolium salt (MTT) was chosen as endpoint. The formazan production of the epidermal tissues treated with the test substance is compared to that of negative control tissues. The quotient of the values indicates the relative tissue viability.

The test substance is not able to reduce MTT directly. The mean viability of the tissues treated with the test substance determined after an exposure period of 1 hour with an about 42-hour post-incubation was 73.7%. Slight compound residues remained on the tissues treated with the test substance after the washing procedure.

Based on the results observed and by applying the evaluation criteria, it was concluded that the test item does not show a skin irritation potential in the EpiDerm™ in vitro skin irritation and corrosion test strategy under the test conditions chosen.