Single Wall Carbon Nanotubes (SWCNT)

Skin irritation / corrosion

Administrative data

Endpoint:

skin corrosion: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

13 July 2016 - 15 July 2016

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2016

Report date:

2016

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:

OECD Guideline for the Testing of Chemicals No. 431 In Vitro Skin Corrosion: Reconstructed Human EpiDermis (RHE) Test Method (28 July 2015).

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 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 Dioxide

Test material form:

solid: nanoform

Details on test material:

Sample Reference: W0167

In vitro test system

Test system:

human skin model

Source species:

human

Cell type:

other: epithelial, derived from human skin, and formed into a stratified, cornified epithelium

Vehicle:

unchanged (no vehicle)

Details on test system:

EpiDerm™ Reconstructed Human Epidermis Model Kit
Supplier : MatTek
EpiDermTM Tissues (0.63cm2) lot number : 23345
Assay Medium lot number : 080716ZSB

Control samples:

yes, concurrent negative control

yes, concurrent positive control

Amount/concentration applied:

25 mg

Duration of treatment / exposure:

3 Minutes
60 minutes

Duration of post-treatment incubation (if applicable):

3 hours

Number of replicates:

2

Results and discussion

In vitro

Results

Results 1

Irritation / corrosion parameter:

% tissue viability

Run / experiment:

3 minutes exposure

Value:

97.8

Vehicle controls validity:

not applicable

Negative controls validity:

valid

Positive controls validity:

valid

Results 2

Irritation / corrosion parameter:

% tissue viability

Run / experiment:

60 minutes exposure

Value:

97.9

Vehicle controls validity:

not applicable

Negative controls validity:

valid

Positive controls validity:

valid

Other effects / acceptance of results:

The MTT solution containing the test item did not turn blue/purple. However, due to an inconclusive result, corrective procedures were run in parallel on freeze-killed tissues as a precaution.
The results obtained showed that no interference due to direct reduction of MTT occurred and it was therefore considered unnecessary to use the results of the freeze-killed tissues for quantitative correction of results or for reporting purposes.
The mean OD562 for the negative control treated tissues was 1.728 for the 3-Minute exposure period and 1.765 for the 60-Minute exposure period. The negative control acceptance criteria were therefore satisfied.
The relative mean tissue viability for the positive control treated tissues was 5.6% relative to the negative control following the 60-Minute exposure period. The positive control acceptance criterion was therefore satisfied.
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 test item was considered to be non-corrosive to the skin.

Executive summary:

A study was performed in accordance with OECD TG 431 to evaluate the corrosivity potential of test item using the EpiDerm™ Human Skin Model after treatment periods of 3 and 60 minutes.

Corrosion is directly related to cytotoxicity in the EpiDerm™ tissue. Cytotoxicity is determined by the reduction of MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl-tetrazolium bromide) to formazan by viable cells in the test item treated tissues relative to the corresponding negative control. The results are used to make a prediction of the corrosivity potential of the test item.

Duplicate tissues were treated with the test item for exposure periods of 3 and 60 minutes. Negative and positive control groups were treated for each exposure period. The test item was found to be inconclusive in the MTT direct reduction test therefore additional non-viable tissues were incorporated into the testing for correction purposes as a precaution. At the end of the exposure period the test item was rinsed from each tissue before each tissue was taken for MTT-loading. After MTT loading each tissue was placed in 2 mL Isopropanol for MTT extraction. At the end of the formazan extraction period each well was mixed thoroughly and triplicate 200 mL samples were transferred to the appropriate wells of a pre-labeled 96-well plate. The optical density (OD) was measured at 562 nm (OD562). Data are presented in the form of percentage viability (MTT reduction in the test item treated tissues relative to negative control tissues).

The relative mean viabilities for each treatment group, with negative control set as 100%, were 97.8% after 3 minutes and 97.9% after 60 minutes. The quality criteria required for acceptance of results in the test were satisfied.

The test item was considered to be non-corrosive to the skin.