Reaction product of trimethylhexamethylenediisocyanate and (3-mercaptopropyl)trimethoxysilane

Skin irritation / corrosion

Administrative data

Endpoint:

skin corrosion: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

The experimental start date was 16 April 2018, and the experimental completion date was 20 April 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

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 431 (In Vitro Skin Corrosion: Human Skin Model Test)

Version / remarks:

29 July 2016

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

other: EC Guideline No. 440/2008. Part B: Methods for the Determination of Toxicity and other health effects, Guideline B.40 BIS: "In Vitro Skin Corrosion: Human Skin Model Test". Official Journal of the European Union No. L142.

Version / remarks:

31 May 2008

Deviations:

no

GLP compliance:

yes

Remarks:

Analyses conducted to support the information cited in the Certificate of Analysis for the test item were not conducted in compliance with the GLP or GMP regulations but under a sponsor or sponsor subcontractor quality system.

Test material

Test material information

Constituent 1

Reference substance name:

2,4,4 TMDI function group 1 + mercaptan, mono-reacted

IUPAC Name:

2,4,4 TMDI function group 1 + mercaptan, mono-reacted

Constituent 2

Reference substance name:

2,4,4 TMDI function group 2 + mercaptan, mono-reacted

IUPAC Name:

2,4,4 TMDI function group 2 + mercaptan, mono-reacted

Constituent 3

Reference substance name:

2,2,4 TMDI function group 1 + mercaptan, mono-reacted

IUPAC Name:

2,2,4 TMDI function group 1 + mercaptan, mono-reacted

Constituent 4

Reference substance name:

2,2,4 TMDI function group 2 + mercaptan, mono-reacted

IUPAC Name:

2,2,4 TMDI function group 2 + mercaptan, mono-reacted

Constituent 5

Reference substance name:

2,2,4 bi-reacted compound

IUPAC Name:

2,2,4 bi-reacted compound

Constituent 6

Reference substance name:

2,4,4 bi-reacted compound

IUPAC Name:

2,4,4 bi-reacted compound

Constituent 7

Reference substance name:

2,4,4-trimethylhexa-1,6-diyl diisocyanate

EC Number:

239-714-4

EC Name:

2,4,4-trimethylhexa-1,6-diyl diisocyanate

Cas Number:

15646-96-5

Molecular formula:

C11H18N2O2

IUPAC Name:

1,6-diisocyanato-2,4,4-trimethylhexane

Constituent 8

Reference substance name:

2,2,4-trimethylhexa-1,6-diyl diisocyanate

EC Number:

241-001-8

EC Name:

2,2,4-trimethylhexa-1,6-diyl diisocyanate

Cas Number:

16938-22-0

Molecular formula:

C11H18N2O2

IUPAC Name:

1,6-diisocyanato-2,2,4-trimethylhexane

Test material form:

liquid

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Source and lot/batch No.of test material: BZA11014
- Expiration date of the lot/batch: 21 April 2018
- Manufacturing date: 21 March 2018

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: At room temperature under nitrogen
- Not stable at higher temperatures

TREATMENT OF TEST MATERIAL PRIOR TO TESTING
- Treatment of test material prior to testing: No correction was made for purity/composition of the test item. The weighed amount of test item was flushed with nitrogen. The liquid item was applied undiluted.

In vitro test system

Test system:

human skin model

Source species:

human

Cell type:

non-transformed keratinocytes

Cell source:

other: Human donors. Tissue is obtained by MatTek Corporation from accredited institutions.

Justification for test system used:

The test is based on the experience that corrosive chemicals show cytotoxic effects following short-term exposure to the stratum corneum of the epidermis. The test is designed to predict and classify the skin corrosion potential of a test item by assessment of its effect on a three-dimensional human epidermis model.

Vehicle:

unchanged (no vehicle)

Details on test system:

RECONSTRUCTED HUMAN EPIDERMIS (RHE) TISSUE
- Model used: EpiDerm
- Tissue batch number(s): 28326
- Delivery date: 18 April 2018
- Date of initiation of testing: 16 April 2018

TEMPERATURE USED FOR TEST SYSTEM
- Temperature used during treatment / exposure: all incubations, with the excepton of the test item incubation of 3 minutes at room temperature, were carried out at 37 +/- 1ºC.

REMOVAL OF TEST MATERIAL AND CONTROLS
-Volume and number of washing steps: After the exposure period, the tissues were washed with phosphate buffered saline (Invitrogen Corporation, Breda, The Netherlands) to remove residual test item. Due to the characteristics of the test item it was difficult to remove and therefore some residual test item could still be left on the skin. The skin inserts were carefully dried. Rinsed tissues were kept in 24 well plates on 300 μL DMEM until 6 tissues (= one application time) were dosed and rinsed.

MTT DYE USED TO MEASURE TISSUE VIABILITY AFTER TREATMENT / EXPOSURE
- MTT concentration: MTT concentrate (5 mg/mL) diluted (1:5) with MTT diluent (supplemented DMEM). Both supplied by MatTek Corporation.
- Incubation time: 3 hours
- Spectrophotometer: TECAN Infinite® M200 Pro Plate Reader
- Wavelength: 570 nm

FUNCTIONAL MODEL CONDITIONS WITH REFERENCE TO HISTORICAL DATA
- Viability: Acceptance criteria: OD (540-570 nm) 1.0 - 3.0. Pass (value: 2.124 +/- 0.066)
- Barrier function: Acceptance criteria: ET-50 3.68 - 8.02 h. Pass (value: 6.13 h)
- No contamination

NUMBER OF REPLICATE TISSUES: Two tissues for a 3-minute exposure and 2 tissues for a 1-hour exposure

NUMBER OF INDEPENDENT TEST SEQUENCES / EXPERIMENTS TO DERIVE FINAL PREDICTION: 1

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 50%, or if the viability after 3 minutes exposure is greater than or equal to 50 % and the viability after 1 hour exposure is less than 15%.
- The test substance is considered to be non-corrosive to skin if the viability after 3 minutes exposure is greater than or equal to 50% and the viability after 1 hour exposure is greater than or equal to 15%.

Control samples:

yes, concurrent negative control

yes, concurrent positive control

Amount/concentration applied:

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 50 µL

NEGATIVE CONTROL
- Amount(s) applied (volume or weight): 50 µL

POSITIVE CONTROL
- Amount(s) applied (volume or weight): 50 µL
- Concentration (if solution): 8N

Duration of treatment / exposure:

3 minutes and 1 hour

Duration of post-treatment incubation (if applicable):

Not applicable

Number of replicates:

2 replicates for each test condition

Results and discussion

In vitro

Results

Results 1

Irritation / corrosion parameter:

% tissue viability

Run / experiment:

3-minutes incubation

Value:

>= 102

Negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

no indication of irritation

Results 2

Irritation / corrosion parameter:

% tissue viability

Run / experiment:

1-hour incubation

Value:

>= 81

Negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

no indication of irritation

Other effects / acceptance of results:

- OTHER EFFECTS:
- Direct-MTT reduction: Not observed
- Colour interference with MTT: Not observed

ACCEPTANCE OF RESULTS:
- Acceptance criteria met for negative control: yes. The absolute mean OD570 of the two tissues of the negative control is within the laboratory historical control data range.
- Acceptance criteria met for positive control: yes . The mean relative tissue viability following 1-hour exposure to the positive control is < 15% (observed value = 6.8%).
- Acceptance criteria met for variability between replicate measurements: yes. In the range 20-100% viability, the coefficient of variation between tissue replicates is <= 30% (obtained value = <=22%).

Any other information on results incl. tables

Mean tissue viability:

	3 -minute application, % viability	1 -hour application, % viability
Negative control	100	100
Test item	102	81
Positive control	14	6.8

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Conclusions:

The Thio Isocyanate Adduct is not corrosive in the in vitro skin corrosion test under the experimental conditions described in this report.

Executive summary:

The study was performed to evaluate Thio Isocyanate Adduct for its ability to induce skin corrosion on a human three dimensional epidermal model (EpiDerm (EPI-200)). The possible corrosive potential of Thio Isocyanate Adduct was tested through topical application for 3 minutes and 1 hour. The study procedures were based on OECD guideline 431 and performed according to GLP. Thio Isocyanate Adduct was applied undiluted (50 μL) directly on top of the skin tissue. The positive control had a mean relative tissue viability of 6.8% after the 1-hour exposure. The absolute mean OD570 (optical density at 570 nm) of the negative control tissues was within the acceptance limits of OECD 431 (lower acceptance limit ≥0.8 and upper acceptance limit <=2.8) and the laboratory historical control data range. In the range of 20 - 100% viability the Coefficient of Variation between tissue replicates was <= 22%, indicating that the test system functioned properly.

Skin corrosion is expressed as the remaining cell viability after exposure to the test item. The relative mean tissue viability obtained after 3-minute and 1-hour treatments with Thio Isocyanate Adduct compared to the negative control tissues was 102% and 81%, respectively. Because the mean relative tissue viability for Thio Isocyanate Adduct was not below 50% after the 3-minute treatment and not below 15% after the 1-hour treatment Thio Isocyanate Adduct is considered to be not corrosive.

In conclusion, Thio Isocyanate Adduct is not corrosive in the in vitro skin corrosion test under the experimental conditions described in this report.