2-(2-methylpropoxy)ethanol

Skin irritation / corrosion

Administrative data

Endpoint:

skin corrosion: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

From 08 March 2018 to 21 March 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 431 (In Vitro Skin Corrosion: Reconstructed Human Epidermis (RHE) Test Method)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

2-(2-methylpropoxy)ethanol

EC Number:

224-658-5

EC Name:

2-(2-methylpropoxy)ethanol

Cas Number:

4439-24-1

Molecular formula:

C6H14O2

IUPAC Name:

2-(2-methylpropoxy)ethan-1-ol

Test material form:

liquid

Details on test material:

- Moisture content: 0.02%
- Acidity (as acetic acid) 0.001%
- Specific gravitiy: 0.892

In vitro test system

Test system:

human skin model

Vehicle:

unchanged (no vehicle)

Details on test system:

RECONSTRUCTED HUMAN EPIDERMIS (RHE) TISSUE
- Model used: MatTek’s EpiDermTM model
- Tissue batch number(s): Lot# 25887
- Delivery date: 20 March 2018
- Date of initiation of testing: 20 March 2018

TEMPERATURE USED FOR TEST SYSTEM
- Temperature used during treatment / exposure: 37°C
DYE BINDING METHOD
- Dye used in the dye-binding assay: MTT
- Spectrophotometer: BMG LabTech FluoStar Optima
- Wavelength: 570 nm
- Filter: None

FUNCTIONAL MODEL CONDITIONS WITH REFERENCE TO HISTORICAL DATA
- Viability: Optical Density (O.D.) values (the mean and SD of MTT value of 3 tissues exposed to sterile water) should be within the Test Guideline acceptance range of 1.0 - 3.0. QC result = 1.609 ± 0.034 = PASS.
- Barrier function: The ET50 of tissues exposed to 100 µL Triton X-100 1%, n=3 should be within the Test Guideline acceptance range of ≥4.77 hours and ≤ 8.72 hours. QC result = 5.18 hours = PASS.
- Morphology: Histological examination should demonstrate human epidermis-like structure: including multiple layers (at least 4) of viable epithelial cells (basal layer, stratum spinosum, stratum granulosum) which are present under multilayered stratum corneum. QC result = 11 layers are present = PASS. Tissue thickness should be within the acceptance range of >70 µm and <130 µm. QC result = 105.6 µm = PASS.
- Contamination: There should be no evidence of contamination during long term antibiotic and antimycotic free culture. QC result = No contamination reported = PASS.

NUMBER OF REPLICATE TISSUES: Triplicate

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): 50µl of neat test item

NEGATIVE CONTROL
- Amount(s) applied (volume or weight): 50 μl of sterile water

POSITIVE CONTROL
- Amount(s) applied (volume or weight): 50 μl of potassium hydroxyde

Duration of treatment / exposure:

3 and 60 minutes

Number of replicates:

Triplicate

Results and discussion

In vitro

Results

Results 1

Irritation / corrosion parameter:

% tissue viability

Run / experiment:

3-minute exposure (mean value)

Value:

87.1

Vehicle controls validity:

not applicable

Negative controls validity:

valid

Positive controls validity:

valid

Results 2

Irritation / corrosion parameter:

% tissue viability

Run / experiment:

60-minute exposure (mean value)

Value:

4.7

Vehicle controls validity:

not applicable

Negative controls validity:

valid

Positive controls validity:

valid

Other effects / acceptance of results:

- OTHER EFFECTS:
- Visible damage on test system: None reported
- Direct-MTT reduction: No interference
- Colour interference with MTT: No interference

ACCEPTANCE OF RESULTS:
- Acceptance criteria met for negative control: Yes
- Acceptance criteria met for positive control: Yes
- Acceptance criteria met for variability between replicate measurements: Yes

Applicant's summary and conclusion

Interpretation of results:

Category 1 (corrosive) based on GHS criteria

Conclusions:

The Relative mean tissue viability calculated as a percentage of the negative control was 87.1% after the 60 minutes exposure and 4.7% after the 3 minutes exposure. The test item meets the criteria for classification as Skin Corr. 1 according to Regulation (EC) No.1272/2008 on the Classification, Labelling and Packaging of Substances and Mixtures.

Executive summary:

 The in vitro skin corrosion of 2-(2-methylpropoxy)ethanol was determined in accordance with the OECD Guideline for Testing of Chemicals 431. The purpose of this test is to evaluate the corrosivity potential of the test item using the EpiDerm™ Reconstituted Human Epidermis after treatment periods of 3 and 60 minutes.

Corrosion is directly related to cytotoxicity in the EpiDerm™ tissue. Cytotoxicity is determined by the reduction of MTT to formazan by viable cells in the test item treated tissues relative to the corresponding negative control. The results are used to make a prediction of the corrosivity potential of the test item.

Prior to the testing, the test substance was checked for interference with water and/or MTT. No interference was identified.

Triplicate tissues were treated with the test item for exposure periods of 3 and 60 minutes. A MTT assay was performed in order to measure the test viability following the exposure to the test substance. The optical density was measured at 570 nm to determine the concentration of formazan produced by the viable cells from the reduction of MTT. Data are presented in the form of percentage viability (MTT reduction in the test item treated tissues relative to negative control tissues).

The Relative mean tissue viability calculated as a percentage of the negative control was 87.1% after the 60 minutes exposure and 4.7% after the 3 minutes exposure. 2-(2-methylpropoxy)ethanol meets the criteria for classification as Skin Corr. 1 according to Regulation (EC) No.1272/2008 on the Classification, Labelling and Packaging of Substances and Mixtures.