3-Isocyanatomethyl-3,5,5-trimethylcyclohexyl isocyanate, oligomers, 2-Hydroxy-1(2)- methylethyl carbamate blocked

Skin irritation / corrosion

Administrative data

Endpoint:

skin corrosion: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2017

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 431 (In Vitro Skin Corrosion: Reconstructed Human Epidermis (RHE) Test Method)

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

2-(carbamoyloxy)propyl N-[(3-{[3,5-bis({5-[({[2-(carbamoyloxy)propoxy]carbonyl}amino)methyl]-1,3,3-trimethylcyclohexyl}methyl)-2,4,6-trioxo-1,3,5-triazinan-1-yl]methyl}-3,5,5-trimethylcyclohexyl)methyl]carbamate

EC Number:

921-910-2

IUPAC Name:

2-(carbamoyloxy)propyl N-[(3-{[3,5-bis({5-[({[2-(carbamoyloxy)propoxy]carbonyl}amino)methyl]-1,3,3-trimethylcyclohexyl}methyl)-2,4,6-trioxo-1,3,5-triazinan-1-yl]methyl}-3,5,5-trimethylcyclohexyl)methyl]carbamate

Test material form:

solid

Details on test material:

- Analytical purity: 83.9 g/100g
- Composition of test material, percentage of components: 0.2g/100g water, 13.4g/100g n-butyl acetate, 2.5g/100g 1,2-propanediol, monocarbamate
- Lot/batch No.: 389-48
- Expiration date of the lot/batch: 2019-05-23

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Source and lot/batch No.of test material: 16/0437-1
- Expiration date of the lot/batch: 389-48

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: room temperature

TREATMENT OF TEST MATERIAL PRIOR TO TESTING
- Treatment of test material prior to testing: The solid test substance was ground with pestle and mortar before application

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: 23388
- 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:

water

Details on test system:

RECONSTRUCTED HUMAN EPIDERMIS (RHE) TISSUE
- Model used: EpiDerm model
- Tissue batch number(s): 23388

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

NUMBER OF REPLICATE TISSUES: 2 tissues per exposure time

PREDICTION MODEL / DECISION CRITERIA (choose relevant statement)
- The test substance is considered to be corrosive to skin if the viability after 3 minutes exposure is less than 45%.
- The test substance is considered to be corrosive to skin if the viability after 3 minutes exposure is higher 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.

Control samples:

yes, concurrent vehicle

Amount/concentration applied:

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 25 µl solid test substance with 25 ml deionized water

Duration of treatment / exposure:

3 minutes at room temperature and 1h in the incubator

Duration of post-treatment incubation (if applicable):

Rinsed tisuues were kept in 24-well plates at room temperature on assay medium until all tissues per application time were dosed and rinsed.

Number of replicates:

2 tissues per exposure time

Results and discussion

In vitro

Results

Results 1

Irritation / corrosion parameter:

% tissue viability

Run / experiment:

Mean (Exposure period: 3 min)

Value:

108.5

Vehicle controls validity:

valid

Negative controls validity:

valid

Positive controls validity:

valid

Results 2

Irritation / corrosion parameter:

% tissue viability

Run / experiment:

Mean (Exposure period: 1h)

Value:

109.5

Vehicle controls validity:

valid

Negative controls validity:

valid

Positive controls validity:

valid

Any other information on results incl. tables

Exposure period 3 minutes: Individual and mean OD570 values, individual and mean viability values and standard deviations

Test substance		Tissue 1	Tissue 2	Mean	SD
NC	Mean OD570	1.527	1.721	1.624
NC	Viability (% of NC)	94.0	106.0	100.0	8.5
Test substance	Mean OD570	1.733	1.792	1.762
Test substance	Viability (% of NC)	106.7	110.4	108.5	26
PC	Mean OD570	0.159	0.244	0.202
PC	Viability (% of NC)	9.8	15.0	12.4	3.7

Exposure period 1h: Individual and mean OD570 values, individual and mean viability values and standard deviations

Test substance		Tissue 1	Tissue 2	Mean	SD
NC	Mean OD570	1.659	1.564	1.612
NC	Viability (% of NC)	102.9	97.1	100.0	4.1
Test substance	Mean OD570	1.807	1.722	1.765
Test substance	Viability (% of NC)	112.1	106.9	109.5	3.7
PC	Mean OD570	0.097	0.085	0.091
PC	Viability (% of NC)	6.0	5.3	5.6	0.5

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 substance does not show a skin corrosion potential under the test conditions chosen.

Executive summary:

The objective was to assess the skin irritation and corrosion potential of the test substance. By using the currently available methods 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).

The potential of the test substance to cause dermal corrosion was assessed by a single topical application of ca. 25 μL bulk volume (about 9 mg) of the undiluted test substance to a reconstructed three-dimensional human epidermis model (EpiDerm™).

For the corrosion test, two EpiDerm™ tissues were incubated with the test substance for 3 minutes and 1 hour, each. Tissue destruction was determined by measuring the metabolic activity of the tissue after

exposure 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 test substance treated epidermal tissues is compared to that of negative control tissues. The quotient of the values indicates the relative tissue viability.

The final mean viability of the tissues treated with the test substance determined after an exposure period of 3 minutes was 108.5% and 109.5% after an exposure period of 1 hour.

Based on the results observed and by applying the evaluation criteria it was concluded that the test substance does not show a skin corrosion potential under the test conditions chosen.