Zirconium oxide, hafnium and ytterbium doped

Skin irritation / corrosion

Administrative data

Endpoint:

skin irritation: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2017-12-08 to 2018-02-09

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

Version / remarks:

Adopted 28 July 2015

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

Zirconium oxide, hafnium and ytterbium doped

EC Number:

945-888-9

Molecular formula:

Yb0.109Hf0.013Zr0.879O1.949

IUPAC Name:

Zirconium oxide, hafnium and ytterbium doped

Test material form:

solid

Details on test material:

- Nam in test report: Ytterbium stabilized Zirconium and Hafnium Oxide
- EC No.: 945-888-9
- Batch No.: 7170502
- Physical state: solid
- Colour: white
- Purity: > 95%
- Expiry date: 26 October 2022
- Storage conditions: room temperature, in a tightly closed container in a dry place

Specific details on test material used for the study:

Name: Ytterbium stabilized Zirconium and Hafnium Oxide
EC No.: 945-888-9
Batch No.: 7170502
Physical State: solid
Colour: white
Purity: > 95%
Expiry Date: 26 October 2022
Storage conditions: room temperature, in a tightly closed container in a dry place

In vitro test system

Test system:

human skin model

Source species:

human

Cell type:

non-transformed keratinocytes

Justification for test system used:

This test uses the EpiDerm™ reconstructed human epidermis model (MatTek) which consists of normal human epidermal keratinocytes (NHEK) and therefore represents in vitro the target organ of the species of interest and 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: EpiDerm™-Standard Model (EPI-200™)
- Tissue batch number(s): 25867

TEMPERATURE USED FOR TEST SYSTEM
- Temperature used during treatment / exposure: 37 ± 1 °C
- Temperature of post-treatment incubation (if applicable): 37 ± 1 °C

REMOVAL OF TEST MATERIAL AND CONTROLS
- Number of washing steps: 1
- Observable damage in the tissue due to washing: None

MTT DYE USED TO MEASURE TISSUE VIABILITY AFTER TREATMENT / EXPOSURE
- MTT concentration: 5 mg/mL
- Incubation time: 60 min
- Wavelength: 570 nm
- Filter bandwidth: +/- 30 nm

NUMBER OF REPLICATE TISSUES: 3 per dose group

CONTROL TISSUES USED IN CASE OF MTT DIRECT INTERFERENCE
- Fresh tissues / killed tissues : Killed tissues
- N. of replicates : 2

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 equal to 50%

Control samples:

yes, concurrent negative control

yes, concurrent positive control

Amount/concentration applied:

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 25 mg

NEGATIVE CONTROL
- Amount(s) applied (volume or weight): 30 µL DPBS

POSITIVE CONTROL
- Amount(s) applied (volume or weight): 30 µL 5% SDS solution

Duration of treatment / exposure:

60 min

Duration of post-treatment incubation (if applicable):

42 h

Number of replicates:

3 per dose group, 3 dose groups

Results and discussion

In vitro

Results

Irritation / corrosion parameter:

% tissue viability

Run / experiment:

Mean of three replicates

Value:

92.8

Negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

no indication of irritation

Other effects / acceptance of results:

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

Any other information on results incl. tables

- The mean absolute OD₅₇₀of the three negative control tissues was ≥0.8 and ≤ 2.8 (1.907)

- The mean relative tissue viability (% negative control) of the positive control was ≤ 20% (3.1%)

- Standard deviation of viability of replicate tissues of all dose groups was ≤ 18% (0.2% - 5.3%)

Table 1: Mean Relative Tissue Viability for the test item

	Negative Control	Positive Control	Test item
Mean Relative Tissue Viability [%]	100.0	3.1	92.8

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Conclusions:

In this study under the given conditions the test item showed no irritant effects. The test item is therefore classified as “non-irritant” in accordance with UN GHS “No Category”.

Executive summary:

In a primary skin irritation study conducted according to the guideline OECD 439, 25 mg of zirconium oxide, hafnium and ytterbium doped (purity > 95 %) was topically applied to the EpiDerm tissue for 60 min followed by a 42 h post-incubation period. Irritant potential of the test item was predicted from the relative mean tissue viabilities obtained compared to the corresponding negative control tissues concurrently treated with DPBS. The controls confirmed the validity of the study. The mean relative tissue viability (% negative control) was observed to be > 50% (92.8%). Based on these results, the test item is classified as a non-irritant under the UN GHS Criteria.