DL-thyroxin

Skin irritation / corrosion

Administrative data

Endpoint:

skin irritation / corrosion, other

Type of information:

experimental study

Adequacy of study:

key study

Study period:

12 december 2018 - 12 february 2019

Reliability:

1 (reliable without restriction)

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)

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

DL-thyroxin

EC Number:

200-101-1

EC Name:

DL-thyroxin

Cas Number:

51-48-9

Molecular formula:

C15H11I4NO4

IUPAC Name:

O-(4-hydroxy-3,5-diiodophenyl)-3,5-diiodotyrosine

Test material form:

solid: particulate/powder

Details on test material:

Name: LEVOTHYROXINE ACID
Batch No.: B486066
Expiry date: 27 August 2020
Storage condition: at room temperature, protected from light
Appearance: white slightly crème, powder

In vitro test system

Test system:

human skin model

Source species:

human

Cell type:

other: EpiSkinTMSM

Vehicle:

unchanged (no vehicle)

Control samples:

yes, concurrent negative control

yes, concurrent positive control

Amount/concentration applied:

10 mg

Duration of treatment / exposure:

15 min

Duration of post-treatment incubation (if applicable):

42 h (± 1h)

Number of replicates:

3

Results and discussion

In vitro

Results

Results 1

Irritation / corrosion parameter:

% tissue viability

Run / experiment:

1

Value:

ca. 120

Negative controls validity:

valid

Positive controls validity:

valid

Results 2

Irritation / corrosion parameter:

% tissue viability

Run / experiment:

2

Value:

ca. 114

Negative controls validity:

valid

Positive controls validity:

valid

Results 3

Irritation / corrosion parameter:

% tissue viability

Run / experiment:

3

Value:

ca. 121

Vehicle controls validity:

valid

Negative controls validity:

valid

Positive controls validity:

valid

Results 4

Irritation / corrosion parameter:

other: Optical Density (OD)

Run / experiment:

1

Value:

ca. 0.884

Vehicle controls validity:

valid

Results 5

Irritation / corrosion parameter:

other: Optical Density (OD)

Run / experiment:

2

Value:

ca. 0.842

Vehicle controls validity:

valid

Results 6

Irritation / corrosion parameter:

other: Optical Density (OD)

Run / experiment:

3

Value:

ca. 0.894

Vehicle controls validity:

valid

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Conclusions:

The results obtained from this in vitro skin irritation test, using the EPISKIN model, indicated that the test item reveals no skin irritation potential under the utilised testing conditions. The test item LEVOTHYROXINE ACID is considered to be non-irritant to skin and is therefore not classified (UN GHS No Category).

Executive summary:

Disks of EPISKIN (three units) were treated with test item and incubated for 15 minutes(± 0.5 min) at room temperature. Exposure of test material was terminated by rinsing with PBS 1x solution. Epidermis units were then incubated at 37±1°C for 42 hours (± 1h) in an incubator with 5±1% CO2, ≥ 95% humidified atmosphere. The viability of each disk was assessed by incubating the tissues for 3 hours (± 5 min) with MTT solution at 37±1°C in 5±1% CO2, ≥ 95% humidified atmosphere, protected from light. The precipitated formazan was then extracted using acidified isopropanol and quantified spectrophotometrically. SDS (5% aq.) and 1×PBS treated (three units / positive and negative control) epidermis were used as positive and negative controls respectively. For each treated tissue viability was expressed as a percentage relative to negative control.The test chemical is identified as requiring classification and labelling according to UN GHS (Category 2 or Category 1), if the mean relative viability after 15 minutes exposure and 42 hours post incubation is less or equal (≤) to 50% of the negative control.In this in vitro skin irritation test using the EPISKIN model, the test item LEVOTHYROXINE ACID did not show significantly reduced cell viability in comparison to the negative control (mean value: 118 %). All obtained test item viability results were above 50 % when compared to the viability values obtained from the negative control. Therefore the test item was considered to be non-irritant to skin.Positive and negative controls showed the expected cell viability values within acceptable limits. The experiment was considered to be valid.