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Toxicological information

Skin irritation / corrosion

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Administrative data

Endpoint:
skin irritation: 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:
2019
Report date:
2019

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
OECD Guideline 439 (In Vitro Skin Irritation: Reconstructed Human Epidermis Test Method)
Version / remarks:
version 28 July 2015
GLP compliance:
yes (incl. QA statement)

Test material

Constituent 1
Chemical structure
Reference substance name:
Cadmium hydroxide
EC Number:
244-168-5
EC Name:
Cadmium hydroxide
Cas Number:
21041-95-2
Molecular formula:
CdH2O2
IUPAC Name:
cadmium hydroxide
Specific details on test material used for the study:
SOURCE OF TEST MATERIAL
- lot/batch No.of test material:
CP5275
- Expiration date of the lot/batch:
04 June 2020
- Purity test date:
98.92%
- Description:White Solid (in the powder form)

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material:
Controlled room temperature (15-25°C, ≤70% relative humidity).
- Safety precautions: Enhanced safety precautions (half mask at least with P3 filter cartridge, nitrile gloves, lab coat) were applied considering the supplied safety datasheet to assure personnel health and safety.

In vitro test system

Test system:
human skin model
Source species:
human
Cell type:
non-transformed keratinocytes
Cell source:
skin obtained from plastic surgery from multiple donors
Vehicle:
unchanged (no vehicle)
Details on test system:
RECONSTRUCTED HUMAN EPIDERMIS (RHE) TISSUE
- Model used: EPISKINTM (SM) (Manufacturer: SkinEthic, France
- Tissue batch number(s):19-EKIN-028
- Expiry Date: 15 July 2019

TEMPERATURE USED FOR TEST SYSTEM
- Temperature used during treatment / exposure: 23.6-25.0°C
- Temperature of post-treatment incubation (if applicable): 37°C

REMOVAL OF TEST MATERIAL AND CONTROLS
-Volume and number of washing steps: 1washing step: rinsing thoroughly with PBS

MTT DYE USED TO MEASURE TISSUE VIABILITY AFTER TREATMENT / EXPOSURE
- MTT concentration: 2 mL of 0.3 mg/mL MTT per well
- Incubation time: 3h
- Spectrophotometer: 96-well plate spectrophotometer
- Wavelength: 570nm

NUMBER OF REPLICATE TISSUES: 3

CONTROL TISSUES USED IN CASE OF MTT DIRECT INTERFERENCE (see any other info on mat and meth)




Control samples:
yes, concurrent negative control
yes, concurrent positive control
yes, concurrent MTT non-specific colour control
Amount/concentration applied:
TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 10 mg

VEHICLE
- Amount(s) applied (volume or weight with unit): na; no formulation was required

NEGATIVE CONTROL: PBS
- Concentration (if solution): 50µl

POSITIVE CONTROL: SDS 5%
- Concentration (if solution): 50µl
Duration of treatment / exposure:
15 minutes (± 0.5 min)
Duration of post-treatment incubation (if applicable):
42h
Number of replicates:
3

Results and discussion

In vitro

Results
Irritation / corrosion parameter:
% tissue viability
Value:
93.1
Vehicle controls validity:
not applicable
Negative controls validity:
valid
Positive controls validity:
valid
Remarks on result:
no indication of irritation

Any other information on results incl. tables

The results of the optical density (OD) measured at 570 nm of each sample and the calculated relative viability % values are presented below: 

 

Table: Optical Density mean (OD) and the calculated relative viability % of the samples

Substance

Optical Density (OD)

 

Viability 

(% RV)

 

Measured

Blank corrected

Negative Control:

1

1.108

1.061

108.2

Phosphate buffered saline

2

0.998

0.952

97.1

 

3

0.975

0.928

94.7

 

mean

--

0.980

100.0

Positive Control:

1

0.099

0.052

5.3

5% (w/v) SDS solution

 

 

2

0.207

0.160

16.3

 

3

0.091

0.044

 

4.5

 

mean

--

0.085

8.7

Test Item:

1

0.884

0.838

85.4

cadmium hydroxide

2

0.963

0.917

93.5

 

3

1.029

0.983

100.2

 

mean

--

0.912

93.1

Notes:

1. Mean blank value was 0.047.

2. Optical density means the mean value of the duplicate wells for each sample

Applicant's summary and conclusion

Interpretation of results:
GHS criteria not met
Conclusions:
In this in vitro EPISKINTM (SM) model test with cadmium hydroxide, the results indicate that the test item is non-corrosive and non-irritant to the skin, UN GHS Classification: No Category.
Executive summary:

An in vitro skin corrosivity and irritation test of cadmium hydroxide was performed in a reconstructed human epidermis model.EPISKINTM(SM) is designed to predict and classify thecorrosivity and irritation potential of chemicals by measuring its cytotoxic effect as reflected in the MTT (3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay. The corrosivity and irritation potential of the test item was evaluated according to theOECD No. 431 and No. 439 guidelines. 

Disks of EPISKINTM(SM) were treated with the test item and incubated for 15 minutes (irritation testing) and 4 hours (corrosivity testing) at room temperature. Exposure of the test item was terminated by rinsing with Phosphate Buffered Saline (PBS). The epidermis units were then incubated at 37°C for 42 hours in an incubator with 5% CO2,in a > 95% humidified atmosphere (irritation testing). The viability of each disk was assessed by incubating the tissues for 3 hours with MTT solution at 37°C in an incubator with 5% CO2 protected from light, in a > 95% humidified atmosphere. The precipitated formazan crystals were then extracted using acidified isopropanol and quantified spectrophotometrically.

Physiological saline (0.9% (w/v) NaCl solution) treated epidermis were used as negative control and glacial acetic acid treated epidermis were used as positive control (two units/control) in case of the corrosivity testing. PBS treated epidermis were used as negative control and 5 % (w/v) Sodium Dodecyl Sulphate (SDS) solution treated epidermis were used as positive control (three units/control) in case of the irritation testing. Two additional disks were used to provide in each case an estimate of colour contribution (NSCliving) from the test item. For each treated tissue, the viability was expressed as a % relative to the negative control. For corrosivity, if the mean relative viability is <35% the test item is considered to be corrosive to skin. For irritation, if the mean relative viability after 15 minutes of exposure and 42 hours post incubation is less or equal (≤) to 50% of the negative control, the test item is considered to be irritant to skin.

Corrosivity testing:

Following exposure with cadmium hydroxide, the mean cell viability was 88.2% compared to the negative control. This is above the threshold of 35%, therefore the test item was considered as being non-corrosive

Irritation testing:

Following exposure with cadmium hydroxide, the mean cell viability was 93.1% compared to the negative control. This is above the threshold of 50%, thereforethe test item was considered as being non-irritant to skin.

 The experiment met thevalidity criteria, therefore the study was considered to be valid.

In conclusion, in this in vitro EPISKINTM(SM) model test with Cadmium hydroxide, the results indicate that the test item is not corrosive and not irritant to the skin, UN GHS Classification: No Category.


 

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