Zinc bis(hydroxymethanesulphinate)

Skin irritation / corrosion

Administrative data

Endpoint:

skin irritation: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

6-14 June 2018

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

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 439 (In Vitro Skin Irritation: Reconstructed Human Epidermis Test Method)

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method B.46 (In Vitro Skin Irritation: Reconstructed Human Epidermis Model Test)

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

Zinc bis(hydroxymethanesulphinate)

EC Number:

246-515-6

EC Name:

Zinc bis(hydroxymethanesulphinate)

Cas Number:

24887-06-7

Molecular formula:

C2H6O6S2Zn

IUPAC Name:

zinc bis(hydroxymethanesulphinate)

impurity 1

Reference substance name:

Zinc sulphite

EC Number:

237-046-8

EC Name:

Zinc sulphite

Cas Number:

13597-44-9

Molecular formula:

H2O3S.Zn

IUPAC Name:

zinc sulfite

Test material form:

solid: particulate/powder

Details on test material:

white crystalline powder
purity: 98.6%
pH of 10% solution: 4.10
bulk density: 1.35

Specific details on test material used for the study:

Batch no: 515

In vitro test system

Test system:

human skin model

Source species:

human

Cell type:

non-transformed keratinocytes

Cell source:

foreskin from a single donor

Vehicle:

unchanged (no vehicle)

Details on test system:

RECONSTRUCTED HUMAN EPIDERMIS (RHE) TISSUE
- Model used: Reconstructed Human epidermis (SkinEthic RHE® model, Episkin SA, RHE/S/17)
- Tissue batch number(s): 18-RHE-064
- Production date: not reported
- Shipping date: not reported
- Delivery date: 12 June 2018
- Date of initiation of testing: 12 June 2018

TEMPERATURE USED FOR TEST SYSTEM
- Temperature used during treatment / exposure: not reported
- Temperature of post-treatment incubation (if applicable): 37°C

REMOVAL OF TEST MATERIAL AND CONTROLS
-Volume and number of washing steps: 42 minutes after the test item application, the human epidermis were washed with 25 x 1 mL of DPBS (Dutscher - Batch No. 9120318).
- Observable damage in the tissue due to washing: none
- Modifications to validated SOP: none

MTT DYE USED TO MEASURE TISSUE VIABILITY AFTER TREATMENT / EXPOSURE
- MTT concentration: 1.0 mg/mL
- Incubation time: 3 hours
- Spectrophotometer: ELx800 absorbance microplate reader
- Wavelength: 570 nm

NUMBER OF REPLICATE TISSUES: 3

CONTROL TISSUES USED IN CASE OF MTT DIRECT INTERFERENCE
There is no direct interaction between the test item and MTT and there is no need to add non- specific coloration controls to the study.

PREDICTION MODEL / DECISION CRITERIA (choose relevant statement)
- The test item is considered as non-irritant to skin in accordance with UN GHS No Category: if the mean percent viability after 42 minutes exposure and 42 hours of post-treatment incubation is > 50%.
- The test item is identified as requiring classification and labelling according to UN GHS (Category 2): if the mean percent tissue viability after 42 minutes exposure and 42 hours of post-treatment incubation is ≤ 50% and the result of a skin corrosion test is “non corrosive”.
- The test item is identified as requiring classification and labelling according to UN GHS (Category 2 or Category 1): if the mean percent tissue viability after 42 minutes exposure and 42 hours of post-treatment incubation is ≤ 50% and in absence of information on a skin corrosion test.

Control samples:

yes, concurrent negative control

yes, concurrent positive control

Amount/concentration applied:

16 mg/0.5 cm2

Duration of treatment / exposure:

42 minutes

Duration of post-treatment incubation (if applicable):

42 hours

Number of replicates:

3

Results and discussion

In vitro

Results

Results 1

Irritation / corrosion parameter:

% tissue viability

Run / experiment:

1

Value:

81.3

Negative controls validity:

valid

Positive controls validity:

valid

Results 2

Irritation / corrosion parameter:

% tissue viability

Run / experiment:

2

Value:

85.5

Negative controls validity:

valid

Positive controls validity:

valid

Results 3

Irritation / corrosion parameter:

% tissue viability

Run / experiment:

3

Value:

87

Negative controls validity:

valid

Positive controls validity:

valid

Other effects / acceptance of results:

Mean tissue viability test item: 84.6 %
Mean tissue viability negative control: 100%
Mean tissue viability positive control (5% sodium dodecyl sulfate): 1.3%

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Conclusions:

In accordance with the Regulation EC No. 1272/2008, the test item ZINC FORMALDEHYDE SULFOXYLATE has to be considered as Non-irritant to skin. It corresponds to UN GHS No Category.

Executive summary:

The aim was to evaluate the possible irritating effects of the test item ZINC FORMALDEHYDE SULFOXYLATE after topical application on in vitro human reconstructed epidermis (SkinEthic RHE model) in accordance with OECD 439 and Test Method B.46 of Council regulation No 761/2009).

The test item was applied as supplied, at the dose of 16 mg to 3 living Reconstructed Human epidermis during 42 minutes. The application was followed by a rinse with 25 mL of DPBS and a 42 hours post-incubation period at 37°C, 5% CO2. Cell viability was then measuered by enzymatc conversion of the vital dye MTT into a blue formazan salt that was quantitatively meausured after extraction from tissues.

The mean percent viability of the treated tissues was 84.6%, versus 1.3% in the positive control (5% SDS).

In accordance with the Regulation EC No. 1272/2008, the test item ZINC FORMALDEHYDE SULFOXYLATE has to be considered as Non-irritant to skin. It corresponds to UN GHS No Category.