9-[2-(2-methoxyethoxy)ethoxy]-9-[3-(oxiranylmethoxy)propyl]-2,5,8,10,13,16-hexaoxa-9-silaheptadecane

Skin irritation / corrosion

Administrative data

Endpoint:

skin irritation: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

Experimental start date 21 September 2016 Experimental completion date 26 September 2016

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2017

Report date:

2017

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method B.46 (In Vitro Skin Irritation: Reconstructed Human Epidermis Model Test)

Deviations:

no

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

9-[2-(2-methoxyethoxy)ethoxy]-9-[3-(oxiranylmethoxy)propyl]-2,5,8,10,13,16-hexaoxa-9-silaheptadecane

EC Number:

289-390-3

EC Name:

9-[2-(2-methoxyethoxy)ethoxy]-9-[3-(oxiranylmethoxy)propyl]-2,5,8,10,13,16-hexaoxa-9-silaheptadecane

Cas Number:

88127-84-8

Molecular formula:

C21H44O11Si

IUPAC Name:

9-[2-(2-methoxyethoxy)ethoxy]-9-{3-[(oxiran-2-yl)methoxy]propyl}-2,5,8,10,13,16-hexaoxa-9-silaheptadecane

Test material form:

liquid

Details on test material:

Batch number: 84246753
Expiry Date: 14 August 2017

Specific details on test material used for the study:

Identification: 9-[2-(2-METHOXYETHOXY)ETHOXY]-9-[3(OXIRANYLMETHOXY)PROPYL]-2,5,8,10,13,16-HEXAOXA-9-SILAHEPTADECANE
Batch: ADC393100
Purity: Not supplied
Physical state/Appearance: Clear colorless liquid
Expiry Date: 17 January 2018
Storage Conditions: Room temperature in the dark

In vitro test system

Test system:

human skin model

Source species:

other: reconstructed human epidermis model

Cell type:

other: Erpidermal

Cell source:

other: reconstructed human epidermis model

Source strain:

other: reconstructed human epidermis model

Details on animal used as source of test system:

3.3.1 EPISKIN™ Reconstructed Human Epidermis Model Kit
Supplier : SkinEthic Laboratories, Lyon, France
Date received : 20 September 2016
EpiSkinTM Tissues (0.38cm2) lot number : 16-EKIN-038
Maintenance Medium lot number : 16-MAIN3-065
Assay Medium lot number : 16-ESSC-041

Justification for test system used:

Following a full validation study the EpiSkinTM reconstructed human epidermis model showed evidence of being a reliable and relevant stand-alone test for predicting rabbit skin irritation when the endpoint is measured by MTT reduction and for being used as a replacement for the Draize Skin Irritation Test for the purpose of distinguishing between Irritating and Non-Irritating test items.

Vehicle:

unchanged (no vehicle)

Details on test system:

10 µL of the test item was added to 2 mL of a 0.3 mg/mL MTT solution freshly prepared in assay medium. The solution was incubated in the dark at 37°C, 5% CO2 in air for 3 hours. Untreated MTT solution was used as a control.

Control samples:

yes, concurrent negative control

yes, concurrent positive control

Amount/concentration applied:

10 µL of the test item was added to 2 mL of a 0.3 mg/mL MTT solution freshly prepared in assay medium.

Duration of treatment / exposure:

15 minutes

Duration of post-treatment incubation (if applicable):

42 hours post exposure

Number of replicates:

12 well plates

Results and discussion

In vitro

Results

Irritation / corrosion parameter:

% tissue viability

Value:

103

Vehicle controls validity:

valid

Negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

no indication of irritation

Other effects / acceptance of results:

The relative mean tissue viability for the positive control treated tissues was 9.5% relative to the negative control treated tissues and the standard deviation value of the viability was 1.3%. The positive control acceptance criteria were therefore satisfied.
The mean OD562 for the negative control treated tissues was 0.875 and the standard deviation value of the viability was 5.0%. The negative control acceptance criteria were therefore satisfied.
The standard deviation calculated from individual tissue viabilities of the three identically test item treated tissues was 5.0%. The test item acceptance criterion was therefore satisfied.

Any other information on results incl. tables

Direct MTT Reduction

The MTT solution containing the test item did not turn blue or purple which indicated that the test item did not directly reduce MTT. 

Assessment of Color Interference with the MTT endpoint

The solution containing the test item was colorless. It was therefore unnecessary to run color correction tissues.

Test Item, Positive Control Item and Negative Control Item

The individual and mean OD₅₆₂values, standard deviations and tissue viabilities for the test item, negative control item and positive control item are given in theappendix. The mean viabilities and standard deviations of the test item and positive control, relative to the negative control are also given in theappendix.

The relative mean viability of the test item treated tissues was 103.0% after a 15‑Minute exposure period and 42‑Hour post‑exposure incubation period.

It was considered unnecessary to perform IL-1aanalysis as the results of the MTT test were unequivocal.

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Conclusions:

The test item was classified as non-irritant. The following classification criteria apply:
EU CLP Not classified for Irritation.
UN GHS Not classified for Irritation (category 3 can not be determined).

Executive summary:

Introduction

The purpose of this test was to evaluate the skin irritation potential of the test item using the EPISKIN^TMreconstructed human epidermis model after a treatment period of 15 minutes followed by a post‑exposure incubation period of 42 hours. The principle of the assay was based on the measurement of cytotoxicity in reconstructed human epidermal cultures following topical exposure to the test item by means of the colorimetric MTT reduction assay. Cell viability is measured by enzymatic reduction of the yellow MTT tetrazolium salt (3‑[4,5-dimethylthiazol-2-yl]-2,5-diphenyl-tetrazolium bromide) to a blue formazan salt (within the mitochondria of viable cells) in the test item treated tissues relative to the negative controls. 

Method

Triplicate tissues were treated with the test item for an exposure period of 15 minutes. At the end of the exposure period each tissue was rinsed before incubating for 42 hours. At the end of the post‑exposure incubation period each tissue was taken for MTT-loading. The maintenance medium from beneath each tissue was transferred to pre‑labeled micro tubes and stored in a freezer for possible inflammatory mediator determination. After MTT-loading a total biopsy of each epidermis was made and placed into micro tubes containing acidified isopropanol for extraction of formazan crystals out of the MTT‑loaded tissues. 

At the end of the formazan extraction period each tube was mixed thoroughly and duplicate 200 µL samples were transferred to the appropriate wells of a pre‑labeled 96‑well plate. The optical density was measured at 562 nm.

Data are presented in the form of percentage viability (MTT reduction in the test item treated tissues relative to negative control tissues).

Results

The relative mean viability of the test item treated tissues was 103.0% after the 15‑Minute exposure period and 42‑Hours post‑exposure incubation period.

Quality criteria: The quality criteria required for acceptance of results in the test were satisfied.

Conclusion

The test item was classified as non-irritant. The following classification criteria apply:

EU CLP Not classified for Irritation.

UN GHS Not classified for Irritation (category 3 can not be determined).