Amides, adipic acid

Skin irritation / corrosion

Administrative data

Endpoint:

skin irritation: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

15 February 2019 to 22 February 2019

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)

GLP compliance:

yes

Test material

Reference

Name:

Unnamed

Type:

Constituent

Test material form:

solid

In vitro test system

Test system:

human skin model

Source species:

human

Cell type:

non-transformed keratinocytes

Cell source:

other: EPISKIN model - reconstructed human epidermis

Details on animal used as source of test system:

reconstructed human epidermis

Vehicle:

physiological saline

Details on test system:

EpiDerm tissues, Lot no.: 29965 were received from MatTek and refrigerated at 2-8°C, Before use the tissues were incubated 37±1°C, 5±1% CO2 with assay medium for one hour equillibrium. The tissues were then moved to new wells with fresh medium for an additional overnight equillibrium, for approximately 18 h. Equillibrium medium was replaced with fresh medium before dosing.

Control samples:

yes, concurrent negative control

yes, concurrent positive control

Amount/concentration applied:

Each test substance-treated tissue was moistened with 25 µL phosphate-buffered saline and 25 mg of test substance solid material were applied to each tisssue
Negative control: 30 µL of DPBS
positive control: 30 µL of 5% SDS solution

Duration of treatment / exposure:

60 min

Duration of post-treatment incubation (if applicable):

42 h

Test system

Vehicle:

physiological saline

Results and discussion

In vitro

Results

Irritation / corrosion parameter:

% tissue viability

Value:

105

Negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

no indication of irritation

Other effects / acceptance of results:

Chemicals that provide tissue viabilities in a range of 30 – 70 % may provide high standard deviation (SD). If the high SD was typical for the chemical and the classification of the chemical was consistent in all independent runs, MatTek recommends that this result be accepted, although it did not meet the Assay Acceptance Criterion.

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Conclusions:

Under the study conditions, the test substance was not irritating to skin.

Executive summary:

A study was conducted to determine the skin irritation potential of the test substance according to OECD Guideline 439 in compliance with GLP. The skin irritation potential was examined using the EpiDerm reconstructed human epidermis model following a treatment period of 60 min and a post-exposure incubation period of 42 h. The principle of the assay is based on the measurement of cytotoxicity in reconstructed human epidermal cultures following topical exposure to the test substance by means of the colorimetric MTT reduction assay. Cell viability is measured by enzymatic reduction of the yellow MTT tetrazolium salt to a blue formazan salt in the substance treated tissues relative to the negative controls. To identify possible interference of the test substance with the MTT endpoint, the test substance was checked for the ability to directly reduce MTT prior to the main assay. On the day of the main test, tissues were treated with the test substance for an exposure period of 60 min. At the end of the exposure period, each tissue was rinsed before incubating for 42 h at 37 ±1°C, 5 ±1% CO2 in air. The relative mean viability of the test substance treated tissues was 105.0 %. Under the study conditions, the test substance was not irritating to skin (Troese, 2019).