Lithium [ethanedioato-O,O’]tetrafluorophosphate

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 2018-12-17 to 2019-03-08

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:

Lithium [ethanedioato-O,O’]tetrafluorophosphate

EC Number:

826-676-4

Cas Number:

521065-36-1

Molecular formula:

LiPF4C2O4

IUPAC Name:

Lithium [ethanedioato-O,O’]tetrafluorophosphate

Specific details on test material used for the study:

Batch No.: 180410
Purity: 99%

In vitro test system

Test system:

human skin model

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): EPI-200, Lot no.: 29674 kit K and L, 29944 kit I and J, 29987 kit C and D

TEMPERATURE USED FOR TEST SYSTEM
- Temperature used during treatment / exposure: 36.3– 37.6°C for 1-hour exposure; room temperature for 3-minutes exposure
- Temperature of post-treatment incubation: 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 (Invitrogen Corporation, Breda, The Netherlands) 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 were used for a 3-minute exposure, two for a 1-hour exposure. For the negative and positive controls, 2 tissues were treated with 50 μL Milli-Q water (negative control) and 2 tissues were treated with 50 μL 8N KOH (positive control) for both the 3-minute and 1-hour time point.

NUMBER OF INDEPENDENT TEST SEQUENCES / EXPERIMENTS TO DERIVE FINAL PREDICTION: 3

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): In the first experiment: 36.41 to 95.16 mg; In the second and third experiment an excessive amount of the test item was applied, so that the skin tissue was completely covered

NEGATIVE CONTROL
- Amount(s) applied: 50 μL

POSITIVE CONTROL
- Amount(s) applied: 50 μL
- Concentration (if solution): 8 N

Duration of treatment / exposure:

3-minute exposure and 1-hour exposure

Number of replicates:

2

Results and discussion

In vitro

Results

Results 1

Irritation / corrosion parameter:

% tissue viability

Run / experiment:

3-minute treatments

Value:

>= 32 - <= 38

Vehicle controls validity:

not applicable

Negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

positive indication of irritation

Results 2

Irritation / corrosion parameter:

% tissue viability

Run / experiment:

1-hour treatments

Value:

>= 0.6 - <= 4

Vehicle controls validity:

not applicable

Negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

positive indication of irritation

Other effects / acceptance of results:

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

ACCEPTANCE OF RESULTS:
- Acceptance criteria met for negative control: 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
- Acceptance criteria met for positive control: The mean relative tissue viability following the 1-hour exposure to the positive control was 6.6, 13 and 7.1%, respectively.
- Acceptance criteria met for variability between replicate measurements: In the range of 20 - 100% viability the Coefficient of Variation between tissue replicates was
≤ 19% for the negative control and test item. Except for tissues treated for 3 minutes with test item in the first two experiments, which had a Coefficient of Variation of 90%, but therefore these experiments were repeated. For the positive control in experiment 2, the Coefficient of Variation between tissue replicates at the 3-minute exposure was 36%. Since both individual tissues were clearly positive it was concluded that the test system functioned properly.

Applicant's summary and conclusion

Interpretation of results:

Category 1 (corrosive) based on GHS criteria

Conclusions:

In conclusion, the test item is corrosive in the in vitro skin corrosion test under the experimental conditions described in this report.

Executive summary:

The ability of test item to induce skin corrosion on a human three dimensional epidermal model (EpiDerm (EPI-200)) was assessed based on most recent OECD 431. The possible corrosive potential of test item was tested through topical application for 3 minutes and 1 hour.

Skin tissue was moistened with 25 μL of Milli-Q water and at least 25 mg of test item was applied directly on top of the skin tissue. In total, 3 experiments were performed. In the first two experiments, after 3 minute exposure to the test item, the individual results of the two tissues were spread over 2 categories, with a subsequent high coefficient of variation, and therefore these experiments were repeated.

The relative mean tissue viability obtained after 3-minute and 1-hour treatments with test item compared to the negative control tissues was 32% and 4.0%, respectively in the first experiment, 38% and 3.6%, respectively in the second experiment, and 41% and 0.6%, respectively in the third experiment. Because the mean relative tissue viability for test item was below 15% after the 1-hour treatment in all three experiments, it is considered to be corrosive.

In conclusion, test item is corrosive in the in vitro skin corrosion test under the experimental conditions described in this report.