Potassium niobate

Skin irritation / corrosion

Administrative data

Endpoint:

skin corrosion: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2017-09-11 to 2017-10-18

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2017

Report date:

2017

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:

Adopted 29th July, 2016

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

Potassium niobate

EC Number:

234-744-4

EC Name:

Potassium niobate

Cas Number:

12030-85-2

Molecular formula:

K.NbO3

IUPAC Name:

niobium(5+) potassium trioxidandiide

In vitro test system

Test system:

human skin model

Source species:

human

Cell type:

non-transformed keratinocytes

Justification for test system used:

The EpiDerm Skin Model is a well-established organotypic, three-dimensional model of the human epidermis and is used for in vitro experiments since many years. It is known for its similarity to human skin.

Vehicle:

water

Details on test system:

RECONSTRUCTED HUMAN EPIDERMIS (RHE) TISSUE
- Model used: EpiDerm^TM
- Tissue bach number(s): 20171402

TEMPERATURE USED FOR TEST SYSTEM
- Temperature used during treatment / exposure: room temperature
- Temperature of post-treatment incubation (if applicable): MTT assay plate incubated at 37+/- 1 °C

EpiDerm Kit:
The EpiDerm^TM tissues were provided as kits (e.g. EPI-200; MatTek), consisting of the following components relevant for this study:
1x sealed plate containing e.g. 24 reconstructed epidermis units (area: 0.63 cm2); each reconstructed epidermis is attached to a cell culture insert and maintained on nutritive agar for transport (Lot: 25841)
2x 24-well plates
4x 6-well plates
1x bottle of assay medium (DMEM-based medium; Lot: 090717TMC)
1x bottle of DPBS Rinse Solution (Lot: 062717MGKA)
25 pieces Nylon Mesh circles (8 mm diameter, 200 µm pore)

REMOVAL OF TEST MATERIAL AND CONTROLS
- Number of washing steps: Using a wash bottle, the tissue will be gently rinsed about 20 times with PBS (phosphate buffered saline) to remove any residual test item


MTT DYE USED TO MEASURE TISSUE VIABILITY AFTER TREATMENT / EXPOSURE
- MTT concentration: MTT stock solution with 5 mg/mL MTT in PBS, diluted 1 + 4 with DMEM-based medium (final concentration: 1 mg/mL)
- Incubation time: 1h
- Spectrophotometer: plate spectrophotometer
- Wavelength: 570 nm

NUMBER OF INDEPENDENT TESTING RUNS / EXPERIMENTS TO DERIVE FINAL PREDICTION:
The test is performed on a total of 4 tissues per dose group, 2 replicas for each treatment period (3 min and 60 min exposure time).

CONTROL TISSUES USED IN CASE OF MTT DIRECT INTERFERNCE
- killed tissue
- N. of replicates: two tissues per treatment period were treated with 25 mg of the test item (KT) and two killed tissues were left untreated
- Method of calculation used: The non-specific colour of additional killed tissues (NSCkilled) was calculated according to: NSCkilled [%] = [ODTKT/ODNK]*100
The true tissue viability is then calculated as the percent tissue viability obtained with living tissues minus NSMTT minus NSCliving plus NSCkilled.

PREDICTION MODEL / DECISION CRITERIA (choose relevant statement)
A test item is classified as non-corrosive if both of the following statements hold true: mean tissue viability after 3 min and 60 min treatment is not decreased to less than 50% and 15% of the corresponding negative control tissues, respectively.
A test item is classified corrosive (C, in accordance with UN GHS category 1) in any case, if the mean tissue viability after 3 min treatment is decreased below 50%: if viability is reduced to less than 50% after 3 min treatment and to more than 15% after 60 min treatment. A test item which decreases viability below 25% after 3 min treatment is classifed as corrosive in accordance with optional UN GHS sub-category 1A.

Control samples:

yes, concurrent negative control

yes, concurrent vehicle

yes, concurrent positive control

Amount/concentration applied:

TEST MATERIAL
- Name: Potassium niobate
- Batch No.: 20171402
- CAS No.: 12030-85-2
- Aggregate state at RT: solid powder
- Colour: white
- Storage conditions: RT, stored in tightly closed container
- Expiry Date: 22 August 2019


- Amount(s) applied (volume or weight with unit): 25 mg of the test substance mixed per 1 mL MTT medium was applied directly atop the EpiDerm^TM tissue.

NEGATIVE CONTROL
- Amount(s) applied (volume or weight): 50 µL distilled water

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

Duration of treatment / exposure:

3 min and 60 min
20 sec. betweeen dosin

Duration of post-treatment incubation (if applicable):

3 h MTT incubation period

Number of replicates:

2 tissues per dose group and time point

Results and discussion

In vitro

Results

Results 1

Irritation / corrosion parameter:

% tissue viability

Remarks:

3 mins exposure

Run / experiment:

Mean of replicates

Value:

88.3

Vehicle controls validity:

not applicable

Negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

no indication of irritation

Results 2

Irritation / corrosion parameter:

% tissue viability

Remarks:

60 minutes exposure

Run / experiment:

Mean of replicates

Value:

91.4

Vehicle controls validity:

not applicable

Negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

no indication of irritation

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 corrosive effects to the skin. The relative mean tissue viability after 3 min 60 min of exposure was > 50%. The test item is therefore considered "non-corrosive” in accordance with UN GHS.

Executive summary:

In a skin corrosion study conducted according to OECD guideline 431, the EpiDerm™-Model was topically exposed to Potassium niobate (Purity > 99.8 %) for 3 mins and 60 mins. Corrosive 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 mean relative tissue viability (% negative control) was > 50% (88.3%) after 3 min treatment and > 15% (91.4%) after 60 min treatment. Based on this result, the test item is classified as a non-corrosive according to the UN GHS..