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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:
2017

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 439 (In Vitro Skin Irritation: Reconstructed Human Epidermis Test Method)
Principles of method if other than guideline:
This in vitro study was performed in order to evaluate the potential of Estragole to evoke skin irritation in a reconstructed human epidermis (RhE) test method.
Skin irritation refers to the production of reversible damage to the skin following the appli-cation of a test chemical.
The test consists of a topical exposure of the neat test item to a human reconstructed epi-dermis model followed by a cell viability test. Cell viability is measured by dehydrogenase conversion of MTT 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazoliumbromid, present in cell mitochondria, into a blue formazan salt that is quantitatively measured after extraction from tissues. The percentage reduction of cell viability in comparison of untreated negative controls is used to predict the skin irritation potential.
GLP compliance:
yes

Test material

Reference
Name:
Unnamed
Type:
Constituent

In vitro test system

Test system:
human skin model
Source species:
human
Cell type:
other: human-derived epidermal keratinocytes
Source strain:
other: human
Details on test system:
The test system is a commercially available EpiDermTM-Kit, procured by MatTek.
The EpiDermTM tissue consists of human-derived epidermal keratinocytes which have been cultured to form a multi-layered, highly differentiated model of the human epidermis. It consists of organized basal, spinous and granular layers, and a multi-layered stratum corneum containing intercellular lamellar lipid layers representing main
lipid classes analogous to those found in vivo. The EpiDermTM tissues are cultured on specially prepared cell culture inserts.


Control samples:
yes, concurrent negative control
yes, concurrent positive control
Duration of treatment / exposure:
60 min
Duration of post-treatment incubation (if applicable):
23 hours and 30 minutes

Test animals

Species:
other: human

Test system

Controls:
yes, concurrent positive control
yes, concurrent negative control

Results and discussion

In vitro

Resultsopen allclose all
Irritation / corrosion parameter:
% tissue viability
Run / experiment:
% Tissue viability (tissue 1)
Value:
15
Negative controls validity:
valid
Positive controls validity:
valid
Irritation / corrosion parameter:
% tissue viability
Run / experiment:
% Tissue viability (tissue 2)
Value:
16.5
Negative controls validity:
valid
Positive controls validity:
valid
Irritation / corrosion parameter:
% tissue viability
Run / experiment:
% Tissue viability (tissue 3)
Value:
17.7
Negative controls validity:
valid
Positive controls validity:
valid
Irritation / corrosion parameter:
% tissue viability
Run / experiment:
% Tissue viability (mean)
Value:
16.4
Negative controls validity:
valid
Positive controls validity:
valid

Applicant's summary and conclusion

Conclusions:
Three tissues of the human skin model EpiDermTM were treated with Estragole for 60 minutes.
The test item was applied directly to each tissue and spread to match the tissue size (0.63 cm2; as indicated by the supplier).
DPBS-buffer was used as negative control, 5% SDS solution was used as positive control.
After treatment with the negative control, the absorbance values were within the required acceptability criterion of 0.8 ≤ mean OD ≤ 2.8, OD was 1.7. The positive control showed clear irritating effects. Relative absorbance was reduced to 3.8% (required:  20%).
Variation within the tissue replicates was acceptable (required: ≤ 18%).

After the treatment with the test item, the relative absorbance values were reduced to 16.4%. This value is below the threshold for skin irritation potential (50%).

Therefore, Estragole is considered as irritant to skin in the Reconstructed Human Epidermis (RhE) Test Method.