1,1-diethoxyethane

Skin irritation / corrosion

Administrative data

Endpoint:

skin corrosion: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

from 2018-09-04 to 2019-01-10

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2019

Report date:

2019

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)

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

other: B.40.bis. In vitro skin corrosion: human skin model test

Version / remarks:

Council Regulation (EC) No. 440/2008

Deviations:

no

Test guideline 3

Qualifier:

according to guideline

Guideline:

other: INVITTOX Protocol SkinEthic™ Skin Corrosivity Test (2012)

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

1,1-diethoxyethane

EC Number:

203-310-6

EC Name:

1,1-diethoxyethane

Cas Number:

105-57-7

Molecular formula:

C6H14O2

IUPAC Name:

1,1-diethoxyethane

Test material form:

liquid

In vitro test system

Test system:

human skin model

Source species:

other: reconstituted human epidermis

Cell type:

non-transformed keratinocytes

Justification for test system used:

The reconstructed human epidermis model in vitro method is an accepted in vitro method to replace animal testing. The human skin RHE™ model closely mimics the biochemical and physiological properties of the upper parts of the human skin, i. e the epidermis.

Vehicle:

unchanged (no vehicle)

Details on test system:

RECONSTRUCTED HUMAN EPIDERMIS (RHE) TISSUE
- Model used: SkinEthic™ RHE-model RHE/S/17
- Tissue batch number: 18-RHE-142
- Date of initiation of testing: On day of receipt the pre-incubation phase of the tissues started.

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

REMOVAL OF TEST MATERIAL AND CONTROLS
- Volume and number of washing steps: rinsed with minimum 20 mL DPBS; excess DPBS was removed by gently shaking the tissue inserts and blotting the bottom of the tissue inserts with blotting paper
- Modifications to validated SOP: none

MTT DYE USED TO MEASURE TISSUE VIABILITY AFTER TREATMENT / EXPOSURE
- MTT concentration: 1 mg/mL
- Incubation time: 3 hours
- Spectrophotometer: microplate reader ELx800, BioTek Instruments GmbH
- Wavelength: 570 nm

NUMBER OF REPLICATE TISSUES: 10

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

PREDICTION MODEL / DECISION CRITERIA
- The test substance is considered to be corrosive to skin category 1 if the viability is more than or equal to 50 % after 3 min and less than 15 % after 1 h exposure or less than 50 % after 3 min exposure.
- The test substance is considered to be non-corrosive to skin if the viability is greater than or equal to 50 % after 3 min and greater than 15 % after 1 h exposure.

Control samples:

yes, concurrent negative control

yes, concurrent positive control

Amount/concentration applied:

Solid test item: 40 ± 3 µL per tissue
Positive control: 40 ± 3 µL per tissue
Negative control: 40 ± 3 µL per tissue

Duration of treatment / exposure:

test item and negative control - 3 min and additional 1 hour
positive control - only 1 hour

Number of replicates:

test item: 2 tissues per time point (3 min and 1 hour)
negative control: 2 tissues per time point (3 min and 1 hour)
positive control: 2 tissues

Results and discussion

In vitro

Results

Results 1

Irritation / corrosion parameter:

% tissue viability

Run / experiment:

test item after 3 min exposure

Value:

>= 50

Vehicle controls validity:

not examined

Negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

positive indication of irritation

Results 2

Irritation / corrosion parameter:

% tissue viability

Run / experiment:

test item after 1 h exposure

Value:

< 15

Vehicle controls validity:

not examined

Negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

positive indication of irritation

Other effects / acceptance of results:

THER EFFECTS
- Direct-MTT reduction: no
- Colour interference with MTT: no

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

Any other information on results incl. tables

Following treatment with the test item, the tissue viability was >50 % after 3 minutes exposure (mean viability: 100.8 %) and <15 % after 1 hour exposure (mean viability: 9.8 %), i.e. according to OECD 431 the test item is considered as corrosive to skin (UN GHS Category 1).

Table 1. Results after treatment of the RHE-model with the test item

Group		Tissue 1		Tissue 2		Mean		CV
		OD	Viability	OD	Viability	OD	Viability	Viability
Negative Control	3 min	1.813	97.9 %	1.891	102.1 %	1.852	100.0 %	3.0 %
	1 hour	1.640	103.9 %	1.515	96.0 %	1.578	100.0 %	5.6 %
Positive Control	1 hour	0.013	0.8 %	0.009	0.6 %	0.011	0.7 %	14.3 %
Test item	3 min	1.806	97.5 %	1.926	104.0 %	1.866	100.8 %	4.6 %
	1 hour	0.166	10.5 %	0.144	9.1 %	0.155	9.8 %	10.2 %

 

Applicant's summary and conclusion

Interpretation of results:

Category 1 (corrosive) based on GHS criteria

Conclusions:

Under the conditions of the study, the test item is considered to possess a corrosive potential to skin (UN GHS Category 1).

Executive summary:

An in vitro study in accordance with the OECD Guideline OECD 431 and EU Method B.40.bis was performed to assess the skin corrosion potential of the test item. Duplicates of the human skin RHE-model were treated with the test item or the negative control for 3 minutes and 1 hour. The positive control was treated only for 1 hour. 40 ± 3 µL of either the negative control (deionised water), the positive control (potassium hydroxide, 8N) or the test item were applied to the tissues.

The test item did not reduce MTT, and it did not indicate colour interference. All of the acceptability criteria were met. After treatment with the positive control (potassium hydroxide, 8N) the mean viability value was 0.7 % and, thus, lower than the historically established threshold of 1.01 %. After treatment with the negative control (deionised water) the mean ODs were 1.852 (3 minutes exposure) and 1.578 (1 hour exposure) and, thus, higher than the historically established thresholds of 1.587 and 1.422, respectively.

Following treatment with the test item, the tissue viability was >50 % after 3 minutes exposure (mean viability: 100.8 %) and <15 % after 1 hour exposure (mean viability: 9.8 %), therefore, the test item is considered as corrosive to skin (UN GHS Category 1).