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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
Study period:
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
Qualifier:
according to
Guideline:
OECD Guideline 439 (In Vitro Skin Irritation: Reconstructed Human Epidermis Test Method)
Deviations:
no
GLP compliance:
yes

Test material

Reference
Name:
Unnamed
Type:
Constituent
Type:
impurity
Test material form:
solid: particulate/powder
Details on test material:
Batch : 20180328 (28 March 2018)
Specific details on test material used for the study:
SOURCE OF TEST MATERIAL
- batch No.of test material: n°batch 20180328
- Expiration date of the lot/batch: March 2019

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: room temperature
- Reactivity of the test substance with MTT : Yes (no direct interaction and there is no need to add non-specific coloration controls to the study)

In vitro test system

Test system:
human skin model
Source species:
human
Cell type:
non-transformed keratinocytes
Cell source:
other: SkinEthic RHE® model
Details on test system:
Test model :
- Source: EPISKIN - reconstructed human epidermis - supplied by SkinEthic Laboratories, Nice, France
- batch: 18-RHE-060
- Received : 05 June 2018
- Maintenance medium : Episkin SA, batch No. 18 SMM 021
- Quality control : histological observation, cell viability and barrier fucton integrity test
Control samples:
yes, concurrent negative control
yes, concurrent positive control
Amount/concentration applied:
TEST MATERIAL
- 3 replicates

NEGATIVE CONTROL
- 3 replicates

POSITIVE CONTROL
- 3 replicates

REMOVAL OF TEST SUBSTANCE
- Washing: Yes with 25 x 1 mL of DPBS (Dutscher - Batch No. 9120318).
- Time after start of exposure: 42 minutes

OBSERVATION
The cell viability was quantified by measurement of the cell succinate dehydrogenase activity
The measured Optical Density (OD), after extraction from tissues, are proportional to the number of living cells.

SCORING SYSTEM:
For each tissue, OD values and calculated percentage cell viability data for the test item, positive and negative controls,
Duration of treatment / exposure:
42 minutes
Duration of post-treatment incubation (if applicable):
42 hoours
Number of replicates:
3

Results and discussion

In vitro

Results
Irritation / corrosion parameter:
% tissue viability
Value:
ca. 2.1
Negative controls validity:
valid
Positive controls validity:
valid
Remarks:
1.7%
Remarks on result:
positive indication of irritation
Remarks:
mean score from three replicates

Any other information on results incl. tables

Assessment of the skin irritation – individual and average values of OD after 42 minutes exposure

 

Application: 16 mg of the test item on 0.50 cm² human skin model

 

 

OD

Mean OD/ disc

Mean OD/ product

Viability %

Mean Viability %

SD viability

Conclusion

Negative control

1

0.646

0.598

108.0

100

7.0

7.0

-

2

0.573

95.8

3

0.575

96.2

Positive control

1

0.010

0.010

1.7

1.7

0.1

0.1

Irritant

2

0.011

1.8

3

0.010

1.7

Test item

1

0.010

0.012

1.7

2.1

0.4

0.4

Irritant or corrosive

2

0.015

2.5

3

0.012

2.0

Applicant's summary and conclusion

Interpretation of results:
other: Irritant or corrosive
Conclusions:
The mean percent viability of the treated tissues was 2.1%, versus 1.7% in the positive control (5% Sodium Dodecyl Sulfate).
In accordance with the Regulation EC No. 1272/2008 and in absence of information on skin corrosion, the test item Paraphenoxyphenol has to be classified in Category 2 “Irritating to skin” or in Category 1 “Corrosive”.
Executive summary:

In accordance with the OECD guideline n°439, the test item Paraphenoxyphenol was applied as supplied, during 42 minutes, at the dose of 16 mg, to 3 living Reconstructed Human epidermis (SkinEthic RHE® model) previously moistened with 10 μL of distilled water. 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 measured by enzymatic conversion of the vital dye MTT into a blue formazan salt that was quantitatively measured after extraction from tissues.

The mean percent viability of the treated tissues was 2.1%, versus 1.7% in the positive control (5% Sodium Dodecyl Sulfate).

In accordance with the Regulation EC No. 1272/2008 and in absence of information on skin corrosion, the test item Paraphenoxyphenol has to be classified in Category 2 “Irritating to skin” or in Category 1 “Corrosive”.