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Description of key information

Key value for chemical safety assessment

Skin irritation / corrosion

Link to relevant study records

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Endpoint:
skin corrosion: 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
Qualifier:
according to
Guideline:
OECD Guideline 431 (In Vitro Skin Corrosion: Reconstructed Human Epidermis (RHE) Test Method)
Deviations:
no
GLP compliance:
yes
Test system:
human skin model
Source species:
human
Details on animal used as source of test system:
EpiDerm™ Reconstructed Human Epidermis Model Kit
Supplier : MatTek
Date received : 24 May 2016
EpiDermTM Tissues (0.63cm2) lot number : 23338
Assay Medium lot number : 051916TMA
Upon receipt of the EpidermTM tissues, the sealed 24-well plate was stored in a refrigerator until use.
Vehicle:
unchanged (no vehicle)
Control samples:
yes, concurrent negative control
yes, concurrent positive control
Amount/concentration applied:
50 uL
Duration of treatment / exposure:
3 minute
60 minute
Duration of post-treatment incubation (if applicable):
3 hours
Irritation / corrosion parameter:
% tissue viability
Run / experiment:
3 minute
Value:
95.4
Negative controls validity:
valid
Positive controls validity:
valid
Irritation / corrosion parameter:
% tissue viability
Run / experiment:
60 minute
Value:
101.7
Negative controls validity:
valid
Positive controls validity:
valid

    Exposure Period

       Percentage Viability

 Negative Control  Positive Control  Test Item
 3 minute  100*  2.6  95.4
 60 minute  100* 3.2  101.7 
Interpretation of results:
GHS criteria not met
Conclusions:
The test item was considered to be non-corrosive to the skin.
Executive summary:

Introduction

The purpose of this test is to evaluate the corrosivity potential of the 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.

Methods

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. 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 μL 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).

Results

Quality criteria: The quality criteria required for acceptance of results in the test were satisfied.

Conclusion

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

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
Qualifier:
according to
Guideline:
OECD Guideline 439 (In Vitro Skin Irritation: Reconstructed Human Epidermis Test Method)
Deviations:
no
GLP compliance:
yes
Test system:
human skin model
Source species:
human
Vehicle:
unchanged (no vehicle)
Details on test system:
EPISKIN™ Reconstructed Human Epidermis Model Kit
Supplier : SkinEthic Laboratories, Lyon, France
Date received : 21 June 2016
EpiSkinTM Tissues (0.38cm2) lot number : 16-EKIN-025
Maintenance Medium lot number : 16-MAIN3-040
Assay Medium lot number : 16-ESSC-025
Control samples:
yes, concurrent negative control
yes, concurrent positive control
Amount/concentration applied:
10 uL
Duration of treatment / exposure:
15 minutes
Duration of post-treatment incubation (if applicable):
42 hours
Number of replicates:
3
Irritation / corrosion parameter:
% tissue viability
Run / experiment:
15 minutes
Value:
77.8
Negative controls validity:
valid
Positive controls validity:
valid

Mean OD562 Values and Viabilities for the Negative Control Item, Positive Control Item and Test Item

Item

 OD562 of tissues Mean OD562 of triplicate tissues  ± SD of OD562   Relative individual tissue viability (%)  Relative mean viability (%)  ± SD of Relative mean viability (%)
 Negative Control Item         0.724 0.641

0.072

112.9

100+

11.2

0.596

93.0

0.602

93.9

     Positive Control Item  

0.025

0.023

0.002

3.9

3.6

0.3

0.023

3.6

0.022

3.4


Test Item        

0.555

0.499

0.049

86.6

77.8

7.6

0.468

73.0

0.473

73.8

OD = Optical Density

SD = Standard deviation

∗ = The mean viability of the negative control tissues is set at 100%

Interpretation of results:
GHS criteria not met
Conclusions:
The test item was classified as non-irritant. The following classification criteria apply: EU CLP Not classified for Irritation. UN GHS Not classified for Irritation (category 3 can not be determined).
Executive summary:

Introduction

The purpose of this test was to evaluate the skin irritation potential of the test item using the EPISKINTM reconstructed human epidermis model after a treatment period of 15 minutes followed by a post-exposure incubation period of 42 hours. The principle of the assay was

based on the measurement of cytotoxicity in reconstructed human epidermal cultures following topical exposure to the test item by means of the colorimetric MTT reduction assay. Cell viability is measured by enzymatic reduction of the yellow MTT tetrazolium salt (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl-tetrazolium bromide) to a blue formazan salt (within the mitochondria of viable cells) in the test item treated tissues relative to the negative controls.

Method

Triplicate tissues were treated with the test item for an exposure period of 15 minutes. At the end of the exposure period each tissue was rinsed before incubating for 42 hours. At the end of the post-exposure incubation period each tissue was taken for MTT-loading. The maintenance medium from beneath each tissue was transferred to pre-labeled micro tubes and stored in a freezer for possible inflammatory mediator determination. After MTT-loading a total biopsy of each epidermis was made and placed into micro tubes containing acidified

isopropanol for extraction of formazan crystals out of the MTT-loaded tissues. At the end of the formazan extraction period each tube was mixed thoroughly and duplicate 200 μL samples were transferred to the appropriate wells of a pre-labeled 96-well plate. The optical density was measured at 562 nm. Data are presented in the form of percentage viability (MTT reduction in the test item treated tissues relative to negative control tissues).

Results

The relative mean viability of the test item treated tissues was 77.8% after the 15-Minute exposure period and 42-Hours post-exposure incubation period.

Quality criteria: The quality criteria required for acceptance of results in the test were

satisfied.

Conclusion

The test item was classified as non-irritant. The following classification criteria apply: EU CLP Not classified for Irritation. UN GHS Not classified for Irritation (category 3 can not be determined).

Endpoint conclusion
Endpoint conclusion:
no adverse effect observed (not irritating)

Eye irritation

Link to relevant study records
Reference
Endpoint:
eye 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
Qualifier:
according to
Guideline:
OECD Guideline 437 (Bovine Corneal Opacity and Permeability Test Method for Identifying i) Chemicals Inducing Serious Eye Damage and ii) Chemicals Not Requiring Classification for Eye Irritation or Serious Eye Damage)
Deviations:
no
GLP compliance:
yes
Species:
cattle
Vehicle:
unchanged (no vehicle)
Controls:
yes, concurrent positive control
yes, concurrent negative control
Amount / concentration applied:
0.75 mL
Duration of treatment / exposure:
10 minutes
Duration of post- treatment incubation (in vitro):
120 minutes
Number of animals or in vitro replicates:
3
Details on study design:
Preparation of Corneas
All eyes were macroscopically examined before and after dissection. Only corneas free of damage were used. The cornea from each selected eye was removed leaving a 2 to 3 mm rim of sclera to facilitate handling. The iris and lens were peeled away from the cornea. The isolated corneas were immersed in a dish containing HBSS until they were mounted in Bovine Corneal Opacity and Permeability (BCOP) holders. The anterior and posterior chambers of each BCOP holder were filled with complete Eagle’s Minimum Essential Medium (EMEM) without phenol red and plugged. The holders were incubated at 32 ± 1 ºC for 60 minutes. At the end of the incubation period each cornea was examined for defects. Only corneas free of damage were used.

Selection of Corneas and Opacity Reading
The medium from both chambers of each holder was replaced with fresh complete EMEM. A pre-treatment opacity reading was taken for each cornea using a calibrated opacitometer. The average opacity for all corneas was calculated. Three corneas with opacity values close to the median value of all corneas were allocated to the negative control. Three corneas were also allocated to the test item and three corneas to the positive control item.

Treatment of Corneas
The EMEM was removed from the anterior chamber of the BCOP holder and 0.75 mL of the test item or control items were applied to the appropriate corneas. The holders were gently tilted back and forth to ensure a uniform application of the item over the entire cornea. Each holder was incubated, anterior chamber uppermost, at 32 ± 1 ºC for 10 minutes. At the end of the exposure period the test item and control items were removed from the anterior chamber and the cornea was rinsed three times with fresh complete EMEM containing phenol red before a final rinse with complete EMEM without phenol red. The anterior chamber was refilled with fresh complete EMEM without phenol red. A posttreatment opacity reading was taken and each cornea was visually observed. The holders were incubated, anterior chamber facing forward, at 32 ± 1 ºC for 120 minutes. After incubation the holders were removed from the incubator, the medium from both chambers was replaced with fresh complete EMEM and a final opacity reading was taken. Each cornea was visually observed.

Application of Sodium Fluorescein
Following the final opacity measurement the permeability of the corneas to sodium fluorescein was evaluated. The medium from the anterior chamber was removed and replaced with 1 mL of sodium fluorescein solution (4 mg/mL). The dosing holes were plugged and the holders incubated, anterior chamber uppermost, at 32 ± 1 ºC for 90 minutes.

Permeability Determinations
After incubation the medium in the posterior chamber of each holder was decanted and retained. 360 μL of medium representing each cornea was applied to a designated well on a 96-well plate and the optical density at 492 nm (OD492) was measured using the Anthos 2001 microplate reader.

Histopathology
The corneas were retained after testing for possible conduct of histopathology. Each cornea was placed into a pre-labeled tissue cassette fitted with a histology sponge to protect the endothelial surface. The cassette was immersed in 10% neutral buffered formalin.
Irritation parameter:
in vitro irritation score
Value:
1.1
Negative controls validity:
valid
Positive controls validity:
valid
Interpretation of results:
GHS criteria not met
Conclusions:
No category. Not requiring classification to UN GHS or EU CLP.
Executive summary:

Introduction

The purpose of this test was to identify test items that can induce serious eye damage and to identify test items not requiring classification for eye irritation or serious eye damage. The Bovine Corneal Opacity and Permeability (BCOP) test method is an organotypic model that provides short-term maintenance of normal physiological and biochemical function of the bovine cornea in vitro. In this test method, damage by the test item is assessed by quantitative measurements of changes in corneal opacity and permeability. The test method can correctly identify test items (both chemicals and mixtures) inducing serious eye damage as well as those not requiring classification for eye irritation or serious eye damage, as defined by the United Nations (UN) Globally Harmonized System of Classification and Labelling of Items (GHS) and EU Classification, Labelling and Packaging (CLP) of chemicals (Regulation (EC) No 1272/2008), and it was therefore endorsed as scientifically valid for both purposes. Test items inducing serious eye damage are classified as UN GHS and EU CLP Category 1. Items not classified for eye irritation or serious eye damage are defined as those that do not meet the requirements for classification as UN GHS/EU CLP Category 1 or 2 (2A or 2B), i.e. they are referred to as UN GHS/EU CLP No Category.

Method

The undiluted test item was applied for 10 minutes followed by an incubation period of 120 minutes. Negative and positive control items were tested concurrently. The two endpoints, decreased light transmission through the cornea (opacity) and increased passage of sodium fluorescein dye through the cornea (permeability) were combined in an empirically derived formula to generate an In Vitro Irritancy Score (IVIS).

Data Interpretation

The test item is classified according to the prediction model as follows:

IVIS  Classification
 ≤ 3  No category. Not requiring classification to UN GHS or EU CL
  > 3; ≤55  No prediction of eye irritation can be made
 > 55  Category 1. UN GHS or EU CLP Causes serious eye damage

Results

The In Vitro irritancy scores are summarized as follows:

 Treatment  In Vitro Irritancy Score
 Test Item  1.1
 Negative Control

 0.4

 Positive Control  118.0

Conclusion

No category. Not requiring classification to UN GHS or EU CLP.

Endpoint conclusion
Endpoint conclusion:
no adverse effect observed (not irritating)

Additional information

Justification for classification or non-classification