1,4-bis(methoxymethyl)benzene

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 2018-12-03 to 2018-12-07

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

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

2016

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

1,4-bis(methoxymethyl)benzene

EC Number:

229-828-2

EC Name:

1,4-bis(methoxymethyl)benzene

Cas Number:

6770-38-3

Molecular formula:

C10H14O2

IUPAC Name:

1,4-bis(methoxymethyl)benzene

Test material form:

liquid

Specific details on test material used for the study:

Batch No.: A7503
Purity: 99.89%

In vitro test system

Test system:

human skin model

Source species:

human

Cell type:

non-transformed keratinocytes

Justification for test system used:

Recommended test system in international guidelines (OECD and EC).

Vehicle:

unchanged (no vehicle)

Details on test system:

RECONSTRUCTED HUMAN EPIDERMIS (RHE) TISSUE
- Model used: EpiDerm Skin Model
- Tissue batch number(s): 29642
- Date of initiation of testing: 03 Dec 2018

TEMPERATURE USED FOR TEST SYSTEM
- Temperature used during treatment / exposure: incubation of 3 minutes at room
temperature, others at 36.4 – 37.1°C
- Temperature of post-treatment incubation (if applicable): 37°C

REMOVAL OF TEST MATERIAL AND CONTROLS
-Volume and number of washing steps: After the exposure period, the tissues were washed with phosphate buffered saline to remove residual test item. 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).
- Incubation time: 3 hours
- Spectrophotometer: TECAN Infinite® M200 Pro Plate Reader
- Wavelength: 570 nm

NUMBER OF REPLICATE TISSUES: Two tissues for a 3-minute and two for a 1-hour exposure, 2 tissues for negative control and 2 tissues for positive control

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%.
- The test substance is considered to be non-corrosive to skin after the 3-minute treatment is considered corrosive if the relative tissue viability after 1-hour treatment with the test item is decreased below 15%.

Control samples:

yes, concurrent negative control

yes, concurrent positive control

Amount/concentration applied:

TEST MATERIAL
- Amount(s) applied: 50 μL

NEGATIVE CONTROL
- Amount(s) applied: 50 μL Milli-Q water

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

Duration of treatment / exposure:

3-minute and 1 hour

Number of replicates:

2

Results and discussion

In vitro

Results

Results 1

Irritation / corrosion parameter:

% tissue viability

Run / experiment:

3-minute treatment

Value:

83

Negative controls validity:

valid

Positive controls validity:

valid

Results 2

Irritation / corrosion parameter:

% tissue viability

Run / experiment:

1-hour treatments

Value:

71

Negative controls validity:

valid

Positive controls validity:

valid

Other effects / acceptance of results:

- OTHER EFFECTS:
- Direct-MTT reduction and Colour interference with MTT: the test item did not interfere with the MTT endpoint because the solutions did not turn blue / purple nor a blue / purple precipitate was observed.

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:

other: not corrosive

Conclusions:

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

Executive summary:

The objective of this study was to evaluate test item for its ability to induce skin corrosion on a human three dimensional epidermal model (EpiDerm (EPI-200)) according to OECD 431. The possible corrosive potential of test item was tested through topical application for 3 minutes and 1 hour.

The test item was applied undiluted (50 μL) directly on top of the skin tissue. The positive control had a mean relative tissue viability of 4.2% 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 <= 11%, 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 test item compared to the negative control tissues was 83% and 71%, respectively. Because the mean relative tissue viability for test item was not below 50% after the 3-minute treatment and not below 15% after the 1-hour treatment test item is considered to be not corrosive.

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