Tin dioxide

Skin irritation / corrosion

Administrative data

Endpoint:

skin irritation: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

from 7th February 2012 to 10th February 2012

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2012

Report date:

2012

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

other: OECD No. 431. In vitro skin corrosion:Human skin model test.13 April 2004

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method B.40 (In Vitro Skin Corrosion: Transcutaneous Electrical Resistance Test (TER))

Deviations:

no

GLP compliance:

yes

Test material

Test material information

1

Reference substance name:

Tin dioxide

EC Number:

242-159-0

EC Name:

Tin dioxide

Cas Number:

18282-10-5

Molecular formula:

O2Sn

IUPAC Name:

tin(4+) dioxidandiide

Test material form:

solid: nanoform

Details on test material:

SOURCE OF TEST MATERIAL
- Source and lot/batch number of test material:
2012-000203
- Expiration date of the lot/batch:
07/02/2013, W0167
- Purity test date:
> 99.9%, 23/01/2011



INFORMATION ON NANOMATERIALS
- Chemical Composition:
Tin Dioxide
- Density:
6.936 g/cm³
- Particle size & distribution:
10-100 nm; 78
- Specific surface area: 7.4293 ± 0.0132 m²/g

In vitro test system

Test system:

human skin model

Vehicle:

unchanged (no vehicle)

Control samples:

yes, concurrent negative control

yes, concurrent positive control

Test animals

Species:

other: human skin models: EpiDerm(TM)

Strain:

other: human skin models: EpiDerm(TM)

Details on test animals or test system and environmental conditions:

not applicable

Test system

Type of coverage:

open

Preparation of test site:

other: not applicable

Vehicle:

water

Controls:

other: not applicable

Amount / concentration applied:

25 mg of the test item was applied directly atop the EpiDermTM tissue using an application spoon avoiding compression of the test item. To ensure good contact with the skin the test item was moistured with 25 µl of water. The test item was spead to match size of the tissue.

Duration of treatment / exposure:

3 and 60 minutes.

Observation period:

one single application.

Number of animals:

not applicable

Details on study design:

Upon receipt of the EpiDermTM - kit, the tissues were transferred into 6-well plates containing 900 µL prewarmed assay medium per well. The 6-well plates were pre-incubated in a humidified incubator at 37 ± I °C, 5.0% CO2 / 95% air for at least 1 h. Then the medium was replaced by 900 µL fresh assay medium. The 6-well plate used for the 3 min. experiment was placed back into the incubator. The other plate was used for the 60 min treatment. About 1 h before the end of the first treatment period the MTT solution was prepared by mixing the MT’ concentrate with the MTT diluent and pre-warmed in the incubator.

60 min experiment: the tissues were treated with each dose group in duplicate, starting with the negative control. Start time was recorded with dosing of the first tissue. Then the 6-well plate was incubated at 37 ± 1 °C, 5.0% CO2 / 95% air.

3 min experiment: the tissues were treated with each dose group in duplicate, starting with the negative control. Start time was recorded with dosing of the first tissue. A constant time interval of 20 sec. was kept between dosing.
After 3 min of application, with foreceps, the first insert was removed from the 6-well plate. Using a wash bottle the tissue was gently rinsed about 20 times with PBS (phosphate buffered saline) to remove any residual test item. Excess PBS was removed by gently shaking the insert and blotting bottom with blotting paper. The insert was placed in a prepared 24-well “holding plate” containing 300 µL prewarmed assay medium per well. All inserts were treated in the same manner.
Then the inserts were transferred into a prepared 24-well “MTT assay plate” containing 300 µL prewarmed MTT solution. The plate was incubated for 3 h at 37 ± I °C, 5.0% CO2 / 95% air.

60 min experiment: after 60 min application, with foreceps, the first insert was removed from the 6-well plate. Using a wash bottle the tissue was gently rinsed about 20 times with PBS to remove any residual test item. Excess PBS was removed by gently shaking the insert and blotting bottom with blotting paper. All inserts were treated in the same manner.
Then the inserts were transferred into a prepared 24-well “MIT assay plate” containing 300 µL prewarmed MTT solution. The plate was incubated for 3 h at 37 ± 1 DC, 5.0% CO2 / 95% air.

3 min and 60 min experiment: after the 3 h MTT incubation period the MTT solution was aspirated. The wells were refilled with PBS and the PBS was aspirated. The rinsing was repeated twice and the tissues were dried. Then the inserts were transferred into new 24-well “extraction plates”. 2 mL of isopropanol were pipetted into each insert, thus the insert was covered from both sides. The extraction plates were sealed in zip-bags to inhibit isopropanol evaporation. Extraction was carried out over night without shaking at room temperature.
After the extraction period the inserts were pierced with an injection needle to allow the extracts to run through the tissues into the corresponding wells. Then the inserts were discarded and the extraction plates were placed on a shaker for 15 mm.

Per each tissue 3 x 200 µL aliquots of the extract were transferred into a 96-well plate and OD was measured at 550 nm without reference wavelength in a plate spectrophotometer.

Results and discussion

In vitro

Results

Results 1

Irritation / corrosion parameter:

% tissue viability

Run / experiment:

Test item

Value:

ca. 99

Vehicle controls validity:

valid

Negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

no indication of irritation

Results 2

Irritation / corrosion parameter:

% tissue viability

Run / experiment:

Negative control

Value:

ca. 100

Vehicle controls validity:

not examined

Negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

no indication of irritation

Results 3

Irritation / corrosion parameter:

% tissue viability

Run / experiment:

positive control

Value:

ca. 15

Vehicle controls validity:

not applicable

Negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

positive 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. The test item is classified as "non corrosive".