Butyltris[(2-ethyl-1-oxohexyl)oxy]stannane

Acute Toxicity: inhalation

Administrative data

Endpoint:

acute toxicity: inhalation

Data waiving:

study scientifically not necessary / other information available

Justification for data waiving:

the study does not need to be conducted because the substance is classified as corrosive to the skin

Cross-reference

Reason / purpose for cross-reference:

reference to other study

Reference

Endpoint:

skin corrosion: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

23 August 2017 to 24 August 2017

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

2016

Deviations:

no

Qualifier:

according to guideline

Guideline:

other: Method B40 bis of Council Regulation (EC) No 440/2008

Deviations:

no

GLP compliance:

yes

Test system:

human skin model

Source species:

human

Cell type:

non-transformed keratinocytes

Justification for test system used:

Recommended test system in international guidelines

Vehicle:

unchanged (no vehicle)

Details on test system:

RECONSTRUCTED HUMAN EPIDERMIS (RHE) TISSUE
- Model used: Three-dimensional human skin model
- Supplier: MatTek In Vitro Life Science Laboratories, Bratislava, Slovak Republic

ASSESSMENT OF MTT INTERACTING SUBSTANCES
- In order to assess the potential non-specific reduction of the test material, 50 μL of test material was added to 1 mL of 1.0 mg/mL MTT and the colour change was assessed after incubation for 60 minutes at 37 ± 1°C, 5 ± 1% CO2, 95% RH. There was no change in colour therefore the test material did not interact with MTT.

ASSESSMENT FOR COLOUR INTERFERENCE
- 50 μL of test material was added to 0.3 mL of both deionised water and isopropanol and incubated for 60 minutes at 37 ± 1°C, 5 ± 1% CO2, 95% RH. Neither solution become coloured, therefore it was deemed not to have the potential to stain the tissue.

APPLICATION OF TEST MATERIAL AND CONTROL SUBSTANCES
- On the day of receipt EpiDerm™ tissues were transferred to refrigerator at 2 to 8°C and stored overnight. The next day, 1 hour 35 minutes before starting the assay, the tissues were prepared for treatment in labelled 6-well plates.
- The test was performed on a total of four tissues per test material, negative and positive control, out of which two were used for a 3 minute application and two tissues were used for a 1 hour application. A volume of 50 μL of the undiluted test material was applied to each tissue. Further tissues were concurrently treated with 50 μL distilled water (negative control) and with 50 μL 8N potassium hydroxide (positive control).

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

REMOVAL OF TEST MATERIAL AND CONTROLS
- After the 3 minute or 1 hour contact periods, the tissues were washed with phosphate buffered saline (PBS) to remove residual material. The rinsed tissues were kept in 24-well plates (holding plates) until all tissues were dosed and rinsed.

NUMBER OF REPLICATE TISSUES: 2 per exposure time

CELL VIABILITY MEASUREMENTS
- Once all tissues had been rinsed, they were transferred to wells containing 300 μL of 1 mg/mL MTT-medium and were incubated for 3 hours (37 ± 1°C, 5 ± 1% CO2, 95% RH).
- After incubation any resultant colour was extracted with 2 mL isopropanol overnight.
- The optical density of each resultant extract was determined spectrophotometrically at 570 nm and cell viability was calculated for each tissue as a percentage of the mean of the negative control tissue.
- Skin corrosivity potential of the test material was classified according to the remaining cell viability obtained after test material treatment with either of the two treatment times.

DATA EVALUATION
- Assay Acceptance Criteria:
The absolute OD570 of the negative control tissues in the MTT test is an indication of the tissue viability in the testing laboratory after the shipping and storage procedure and under specific conditions of the assay. The OD values for the negative controls should be ≥ 0.8 and ≤ 2.8, for this tissue model.
The OD values for the 60 minute positive controls should be < 15% when compared to that of the negative control.
The CV between the replicates should be ≤ 30%.
Both negative and positive control value must fall within the laboratory historical control values.

- Interpretation of Results:
The OD values obtained for each test sample are used to calculate the percentage viability relative to the negative control, which is arbitrarily set at 100%. The prediction of corrosivity associated with the EpiDerm™ model is as follows:
STEP 1:
< 50 % viability after 3 min exposure = Corrosive
≥ 50 % viability after 3 min exposure and < 15 % viability after 60 min exposure = Corrosive
≥ 50 % viability after 3 min exposure and ≥ 15 % viability after 60 min exposure = Non-corrosive
STEP 2 (for Substances/Mixtures Identified as Corrosive in Step 1):
< 25 % viability after 3 min exposure = Optional Sub-category 1A
≥ 25 % viability after 3 min exposure = A combination of optional Sub-categories 1B and 1C

Control samples:

yes, concurrent negative control

yes, concurrent positive control

Amount/concentration applied:

TEST MATERIAL
- Amount(s) applied: 50 µL

NEGATIVE CONTROL
- Amount(s) applied: 50 µL

POSITIVE CONTROL
- Amount(s) applied: 50 µL
- Concentration: 8.0 N

Duration of treatment / exposure:

3 minutes of exposure and 1 hour of exposure

Duration of post-treatment incubation (if applicable):

Incubated for 3 hours with MTT

Number of replicates:

2 per exposure time

Irritation / corrosion parameter:

% tissue viability

Run / experiment:

3 minute exposure

Value:

27

Vehicle controls validity:

not applicable

Negative controls validity:

valid

Positive controls validity:

valid

Irritation / corrosion parameter:

% tissue viability

Run / experiment:

60 minute exposure

Value:

21.2

Vehicle controls validity:

not applicable

Negative controls validity:

valid

Positive controls validity:

valid

Other effects / acceptance of results:

- Skin viability after a three minute or one hour exposure to the test material was 27 and 21.2%, respectively.
- The OD values for the negative controls met the acceptance criteria.
- Skin viability after a three minute or one hour exposure to the positive control was 3 and 10.7%, respectively, demonstrating appropriate performance of the assay.

Table 1: Summary of Results

Treatment	Mean OD570		% Survival		% CV
	3 minutes	60 minutes	3 minutes	60 minutes	3 minutes	60 minutes
Negative control	1.434	1.351	100	100	10.8	10.5
Test material	0.384	0.287	27	21.2	17.1	8.7
Positive control	0.292	0.354	3	10.7	6.9	15.0

 

Interpretation of results:

other: Corrosive (EU Criteria Category 1)

Conclusions:

Under the conditions of this study the test material was found to be corrosive to skin.

Executive summary:

The potential of the test material to cause skin corrosion was investigated in accordance with the standardised guidelines OECD 431 and EU Method B.40bis, under GLP conditions. The study was conducted using the in vitro skin model EpiDerm™.

During the study, duplicate EpiDerm™ inserts were treated with test material, purified water (negative control) and 8N potassium hydroxide (positive control) for 3 minutes and 1 hour. At the end of the treatment period, the tissues were washed with phosphate buffered saline (PBS) and cell viability was assessed using the MTT assay. The skin corrosivity potential was classified according to the remaining cell viability obtained after test material treatment with either of the two treatment times.

Skin viability after a three minute or one hour exposure to the test material was 27 and 21.2 %, respectively. The OD values for the negative controls met the acceptance criteria. Skin viability after a three minute or one hour exposure to the positive control material was 3 and 10.7 %, respectively, demonstrating appropriate performance of the assay.

Under the conditions of this study the test material was found to be corrosive to skin.