Tetramethylcyclotetrasiloxane substituted dipropylether bisphenol A

Skin irritation / corrosion

Administrative data

Endpoint:

skin corrosion: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

19 August - 21 August 2020

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2021

Report date:

2021

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

18 June 2019

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method B.40 (In Vitro Skin Corrosion: Transcutaneous Electrical Resistance Test (TER))

Version / remarks:

30 May 2008

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

Reaction mass of (Tetramethylcyclotetrasiloxane propylether) prop-1-enylether bisphenol A and Di(tetramethylcyclotetrasiloxane propylether) bisphenol A

Cas Number:

203874-34-4

Molecular formula:

(OSiHxCH3)4-CH2-CH2 -CH2- O-C6H4-C(CH3)2-C6H4-0-CH2-CH2-CH2-(SiHxCH3O)4

IUPAC Name:

Reaction mass of (Tetramethylcyclotetrasiloxane propylether) prop-1-enylether bisphenol A and Di(tetramethylcyclotetrasiloxane propylether) bisphenol A

Test material form:

liquid

Details on test material:

Appearance: Pale yellow liquid

Specific details on test material used for the study:

Storage Conditions: Room temperature in the dark, under nitrogen.
The test item was used as supplied.

In vitro test system

Test system:

human skin model

Source species:

human

Cell type:

non-transformed keratinocytes

Cell source:

foreskin from multiple donors

Vehicle:

unchanged (no vehicle)

Details on test system:

RECONSTRUCTED HUMAN EPIDERMIS (RHE) TISSUE
- Model used: EpiDerm™ Reconstructed Human Epidermis Model (MatTek In Vitro Life Sciences Laboratories, Lot number: 30886).

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

APPLICATION OF THE TEST ITEM
The assay medium was brought to room temperature before use (37°C, 5% CO2). After pre-incubation of the EpiDerm™ tissues, the medium was aspirated and replaced with 0.9 mL of fresh assay medium.
Dosing was done by adding 50 µL of sterile distilled water (negative control), 50 µL of the test item or 50 µL of 8.0 N Potassium Hydroxide (positive control). Tissues were incubated for 3 or 60 mintes at 37°C.
All incubations were done in duplicate.

REMOVAL OF TEST MATERIAL AND CONTROLS
Rinsing was achieved by filling and emptying each tissue under a constant soft stream of Dulbecco’s Phosphate Buffered Saline (DPBS) (without Ca++ Mg++) for approximately 40 seconds, to gently remove any residual test item. Excess DPBS was removed by blotting the bottom of the tissue insert with tissue paper. Each tissue was placed into the prepared holding plate until all tissues were rinsed.

MTT DYE USED TO MEASURE TISSUE VIABILITY AFTER TREATMENT / EXPOSURE
- A pre-test was performed to examine possible interference of the test item with the MTT dye.
- MTT concentration: 1.0 mg/mL MTT solution
- Incubation time: 3 hours
- Spectrophotometer: Labtech LT-4500 microplate reader and LT-com analysis software.
- Wavelength: 570 nm (OD570)
After MTT-loading each tissue was placed in 2 mL of isopropanol for MTT extraction overnight at room temperature. The corrosivity potential of the test item was predicted from the relative mean tissue viabilities obtained after the 3 and 60-Minute exposure periods, compared to the mean of the negative control tissues (n=2) treated with sterile distilled water. The relative mean viabilities were calculated in the following way:
Relative mean viability (%)= ((mean OD570 of test item)/(mean OD570 of negative control))*100.

DECISION CRITERIA:
In the first step:
- 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%.
Prediction to be considered according to EU CLP Regulation (EC) No 1272/2008 UN GHS:
In the second step:
For test items identified as corrosive in step 1:
- Test item would be classified as H314 (Sub-category 1A) if the viability after 3 minutes exposure is less than 25%.
- Test item would be classified as H314 (Combination of sub-categories 1B-and-1C) if the viability after 3 minutes exposure is higher than or equal to 50%.

Control samples:

yes, concurrent negative control

yes, concurrent positive control

Amount/concentration applied:

50 µL

Duration of treatment / exposure:

3 minutes and 60 minutes

Number of replicates:

Duplicate tissues

Results and discussion

In vitro

Results

Results 1

Irritation / corrosion parameter:

% tissue viability

Run / experiment:

After 3 minute exposure period

Value:

97.7

Vehicle controls validity:

valid

Negative controls validity:

not applicable

Positive controls validity:

valid

Remarks:

2.3%

Remarks on result:

no indication of irritation

Results 2

Irritation / corrosion parameter:

% tissue viability

Run / experiment:

After 60 minutes exposure period

Value:

97.3

Vehicle controls validity:

valid

Negative controls validity:

not applicable

Positive controls validity:

valid

Remarks:

1.9%

Remarks on result:

no indication of irritation

Other effects / acceptance of results:

Mean OD570 values and viabilities for the negative control, positive control and test item are given below.

The MTT solution containing the test item did not turn blue/purple. This was taken to indicate the test item did not reduce MTT.

The mean OD570 for the negative control treated tissues was 2.148 for the 3-Minute exposure period and 2.169 for the 60-Minute exposure period. The negative control acceptance criteria were therefore satisfied.
The relative mean tissue viability for the positive control treated tissues was 1.9% relative to the negative control following the 60-Minute exposure period. The positive control acceptance criterion was therefore satisfied.
In the range 20 to 100% viability the Coefficient of Variation between the two tissue replicates of each treatment group did not exceed 30%. The acceptance criterion was therefore satisfied.

Any other information on results incl. tables

Mean OD570 Values and Viabilities for the Negative Control Item, Positive Control Item and Test Item

Tissue	Exposure Period	Mean OD570 of individual tissues	Mean OD570 of duplicate tissues	Standard Deviation	Coefficient of Variation (%)	Relative Mean Viability (%)
Negative Control	3 Minutes	2.174	2.148	0.037	1.7	100*
		2.121
	60 Minutes	2.136	2.169	0.046	2.1
		2.201
Positive Control	3 Minutes	0.062	0.050	0.017	Na	2.3
		0.038
	60 Minutes	0.050	0.042	0.012	Na	1.9
		0.033
Test item	3 Minutes	2.148	2.099	0.070	3.3	97.7
		2.049
	60 Minutes	2.076	2.111	0.049	2.3	97.3
		2.146
* The mean viability of the negative control tissues is set at 100%

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Conclusions:

Based on the results of an in vitro skin corrosion test, performed according to OECD/EC guidelines and under GLP principles, the substance is considered to be non-corrosive to the skin.

Executive summary:

An in vitro skin corrosion test was performed according to OECD/EC guidelines and under GLP principles. Duplicate tissues were treated with the negative control, positive control and test item (50µl each) for exposure periods of 3 and 60 minutes. The percentage viability was assessed by MTT reduction. The test item did not interfere with MTT. The mean viabilities were 100%, 2.3% and 97.7% for the vehicle control, the positive control and for the test item, respectively, after 3 minutes exposure. After 60 minutes exposure the viabilities were 100%, 1.9% and 97.3% for the vehicle control, the positive control and for the test item, respectively. The criteria required for acceptance of results in the test were satisfied.
This data indicates that the test item does not have skin corrosive properties.