Tetraethylammonium tetrafluoroborate

Skin irritation / corrosion

Administrative data

Endpoint:

skin irritation: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1 October - 14 November 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

Test guideline 1

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

adopted 28 July 2015

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

Official Journal of the European Union No. L142; Amended by EC No. 640/2012 OJ No. L193, 20 July 2012

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

tetraethylammonium tetrafluoroborate

Cas Number:

429-06-1

Molecular formula:

C8H20BF4N

IUPAC Name:

tetraethylammonium tetrafluoroborate

Test material form:

solid: crystalline

In vitro test system

Test system:

human skin model

Source species:

human

Cell type:

other: adult humanderived epidermal keratinocytes

Cell source:

other: the keratinocytes were cultured for 13 days, which results in a highly differentiated and stratified epidermis model comprising the main basal, supra basal, spinous and granular layers and a functional stratum corneum

Justification for test system used:

The test item has been tested previously in the Skin corrosion test using EpiDerm as a skin model and was found not corrosive (Study No. 20162875). In the interest of sound science and animal welfare, a sequential testing strategy is recommended to minimize the need of in vivo testing. One of the validated in vitro skin irritation tests is the EPISKIN test, which is recommended in international guidelines (e.g. OECD and EC).

Vehicle:

not specified

Details on test system:

RECONSTRUCTED HUMAN EPIDERMIS (RHE) TISSUE
- Model used: three dimensional epidermal model (EPISKIN Small model (EPISKIN-SMTM)
- Tissue batch number(s): 18-EKIN-040

TEMPERATURE USED FOR TEST SYSTEM
- Temperature used during treatment / exposure: in the dark at 37.0 ± 1.0°C (actual range 36.8 - 37.3°C)

NUMBER OF REPLICATE TISSUES: 3 tissues per test item

MTT DYE USED TO MEASURE TISSUE VIABILITY AFTER TREATMENT / EXPOSURE
- MTT concentration: 0.3 mg/mL
- Incubation time: 3 h
- Spectrophotometer: TECAN Infinite® M200 Pro Plate Reader
- Wavelength: 570 nm

PREDICTION MODEL / DECISION CRITERIA
- A test item is considered irritant in the skin irritation test if the relative mean tissue viability of three individual tissues after 15 minutes of exposure to the test item and 42 hours of post incubation is ≤ 50% of the mean viability of the negative controls.
- A test item is considered non-irritant in the in vitro skin irritation test if the relative mean tissue viability of three individual tissues after 15 minutes of exposure to the test item and 42 hours of post incubation is > 50% of the mean viability of the negative controls.

Amount/concentration applied:

NEGATIVE CONTROL
- Amount(s) applied (volume or weight): 25 µL (Phosphate buffered saline)

POSITIVE CONTROL
- Amount(s) applied (volume or weight): 25 µL (Sodium dodecyl sulfate)
- Concentration (if solution):5%

MTT-solution
- Amount(s) applied (volume or weight with unit): 2 mL
- Concentration (if solution): 0.3 mg/mL in PBS

Duration of treatment / exposure:

15 ± 0.5 minutes

Test animals

Details on test animals or test system and environmental conditions:

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 37.0 ± 1.0°C (actual range 36.8 - 37.3°C)
- Humidity (%): a humid atmosphere of 80 - 100% (actual range 71 - 86%)
- Air changes (per hr): containing 5.0 ± 0.5% CO2 in air
- Photoperiod (hrs dark / hrs light): in the dark

Results and discussion

In vitro

Results

Irritation / corrosion parameter:

% tissue viability

Remarks:

negative control

Run / experiment:

15 ± 0.5 minutes treatment

Value:

89

Vehicle controls validity:

valid

Negative controls validity:

valid

Remarks on result:

no indication of irritation

Other effects / acceptance of results:

ACCEPTANCE OF RESULTS:
- The relative mean tissue viability obtained after 15 ± 0.5 minutes treatment with the test item compared to the negative control tissues was 89%. The mean relative tissue viability for the test item was above 50% after 15 ± 0.5 minutes treatment.
- The positive control had a mean cell viability of 17% after 15 ± 0.5 minutes exposure.
- The absolute mean OD570 (optical density at 570 nm) of the negative control tissues was within the laboratory historical control data range.
- The standard deviation value of the percentage viability of three tissues treated identically was ≤ 12% for the negative and positive control, indicating that the test system functioned properly.

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Conclusions:

Tetraethylammonium tetrafluoroborate is non-irritant in the in vitro skin irritation test and should not be classified.

Executive summary:

The objective of this study was to evaluate Tetraethylammonium tetrafluoroborate for its ability to induce skin irritation on a human three dimensional epidermal model (EPISKIN Small model (EPISKIN-SMTM)). The possible skin irritation potential of the test item was tested through topical application for 15 minutes.

Skin tissue was moistened with 5 µL of Milli-Q water and an excessive amount of the test item was applied directly on top of the skin tissue for 15 ± 0.5 minutes. After a 42 hour postincubation period, determination of the cytotoxic (irritancy) effect was performed. Cytotoxicity is expressed as the reduction of mitochondrial dehydrogenase activity measured by formazan production from MTT at the end of the treatment.

Skin irritation is expressed as the remaining cell viability after exposure to the test item. The relative mean tissue viability obtained after 15 ± 0.5 minutes treatment with the test item compared to the negative control tissues was 89%. Since the mean relative tissue viability for the test item was above 50% after 15 ± 0.5 minutes treatment the test item is considered to be non-irritant.

The positive control had a mean cell viability of 17% after 15 ± 0.5 minutes exposure. The absolute mean OD570 (optical density at 570 nm) of the negative control tissues was within the laboratory historical control data range. The standard deviation value of the percentage viability of three tissues treated identically was ≤ 12% for the negative and positive control, indicating that the test system functioned properly.

In conclusion, Tetraethylammonium tetrafluoroborate is non-irritant in the in vitro skin irritation test under the experimental conditions described in this report and should not be classified.