Trialuminium bismuth hexaoxide

Skin irritation / corrosion

Administrative data

Endpoint:

skin corrosion: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

key study

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

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

Trialuminium bismuth hexaoxide

EC Number:

235-552-3

EC Name:

Trialuminium bismuth hexaoxide

Cas Number:

12284-76-3

Molecular formula:

Al3BiO6

IUPAC Name:

bismuth;oxido(oxo)alumane

Test material form:

solid

In vitro test system

Test system:

human skin model

Remarks:

EpiDerm™ Reconstructed Human Epidermis Model

Source species:

human

Cell type:

other: The target cells are epithelial, derived from human skin, and formed into a stratified, cornified epithelium

Cell source:

other: Human skin

Source strain:

not specified

Details on animal used as source of test system:

Not applicable. An EpiDerm™ Reconstructed Human Epidermis Model Kit was supplied and used.

Justification for test system used:

Standard as per guideline

Vehicle:

water

Details on test system:

RECONSTRUCTED HUMAN EPIDERMIS (RHE) TISSUE
- Model used: EpiDerm™ Reconstructed Human Epidermis Model
- Tissue batch number(s): 25848
- Production date: Not specified
- Shipping date: Not specified
- Delivery date: 10 October 2017
- Date of initiation of testing: 11 October 2017

TEMPERATURE USED FOR TEST SYSTEM
- Temperature used during treatment / exposure: 37°C
- Temperature of post-treatment incubation (if applicable): 37°C for 3 hours post inucbation

REMOVAL OF TEST MATERIAL AND CONTROLS
- Volume and number of washing steps: Rinsing was achieved by filling and emptying each tissue under a constant soft stream of Dulbecco’s Phosphate Buffered Saline (DPBS) to gently remove any residual test item. Excess DPBS was removed by blotting the bottom of the tissue insert with tissue paper.
- Observable damage in the tissue due to washing: None noted
- Modifications to validated SOP: Not specified

Absorbance/Optical Density Measurements
After extraction, each tissue was pierced with a pipette fitted with a 1000 μL tip and the extraction solution was forced vigorously up and down to form a homogenous solution. Aliquots of the extract were transferred to the appropriate wells of a pre-labeled 96-well plate. Isopropanol alone was added to the three wells designated as blanks. Absorbency at 570nm (OD570) of each well was measured using the Labtech LT-4500 microplate reader.

Direct MTT reduction
A test item may interfere with the MTT endpoint, if it is able to directly reduce MTT and at the same time was present on or in the tissues when the MTT viability test was performed. To identify this possible interference, the test item was checked for the ability to directly reduce MTT according to the following procedure. A sample of the test item was added to freshly prepared 1.0 mg/mL MTT solution. The solution was incubated in the dark at 37 °C, 5% CO2 in air for 60 minutes. Untreated MTT solution was tested concurrently to act as a control. If the MTT solution containing the test item turned blue/purple relative to the control, the test item was presumed to have reduced the MTT.

Assessment of Color Interference with the MTT Endpoint
A test item may interfere with the MTT endpoint if it is colored or if it becomes colored when in wet or aqueous conditions. The MTT assay is affected only if the test item is present in the tissues when the MTT viability assay is performed. A sample of test item was added to sterile water. The solution was incubated in the dark at 37 °C, 5% CO2 in air for 60 minutes. A visual assessment of the color was then made.

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:

no

Amount/concentration applied:

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

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

POSITIVE CONTROL
- Amount(s) applied (volume or weight): 50 µL of 8.0 N potassium hydroxide

Duration of treatment / exposure:

3 and 60 minutes exposure periods

Duration of post-treatment incubation (if applicable):

Not applicable

Number of replicates:

Duplicate tissues were treated with the test item for exposure periods of 3 and 60 minutes.

Results and discussion

In vitro

Results

Results 1

Irritation / corrosion parameter:

% tissue viability

Run / experiment:

3 minute exposure

Value:

97.9

Vehicle controls validity:

valid

Negative controls validity:

not applicable

Positive controls validity:

valid

Remarks on result:

no indication of irritation

Results 2

Irritation / corrosion parameter:

% tissue viability

Run / experiment:

60 minute exposure

Value:

108.1

Vehicle controls validity:

valid

Negative controls validity:

not applicable

Positive controls validity:

valid

Remarks on result:

no indication of irritation

Other effects / acceptance of results:

- OTHER EFFECTS:
- Visible damage on test system: None noted
- Direct-MTT reduction: The MTT solution containing the test item did not turn blue/purple. This was taken to indicate the test item did not reduce MTT.
- Colour interference with MTT: The solution containing the test item did not become colored. This was taken to indicate the test item did not have the potential to cause color interference.

ACCEPTANCE OF RESULTS:
- Acceptance criteria met for negative control: The mean OD570 for the negative control treated tissues was 1.409 for the 3-Minute exposure period and 1.278 for the 60-Minute exposure period. The negative control acceptance criteria were therefore satisfied.
- Acceptance criteria met for positive control: The relative mean tissue viability for the positive control treated tissues was 3.3% relative to the negative control following the 60-Minute exposure period. The positive control acceptance criterion was therefore satisfied.
- Acceptance criteria met for variability between replicate measurements: In the range 20 to 100% viability the Coefficient of Variation between the two tissue replicates of each treatment group did not exceed 30%. The acceptance criterion was therefore satisfied.

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Conclusions:

The percentage viability of the test substance was deemed to be 97.9 and 108.1 in the 3 and 60 minute exposure periods respectively. As such the test substance was deemed to be non-corrosive to skin under the experimental conditions used.