N-2-hydroxyethylacetamide

Skin irritation / corrosion

Administrative data

Endpoint:

skin corrosion: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

From May 16, 2017 to June 16, 2017

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2017

Report date:

2017

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 439 (In Vitro Skin Irritation: Reconstructed Human Epidermis Test Method)

Deviations:

yes

Remarks:

Optical Density (OD) values were obtained with blanks higher than 0.1 (0.191), causing a deviation from the acceptance criteria. However, this is not considered to be an issue in the interpretation of this study data.

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

1

Reference substance name:

Reaction mass of N-2-hydroxyethylacetamide and N,O-diacetyl-2-aminoethanol

Molecular formula:

C4H9NO2 (amide) & C6H11NO3 (amido ester)

IUPAC Name:

Reaction mass of N-2-hydroxyethylacetamide and N,O-diacetyl-2-aminoethanol

Test material form:

liquid

In vitro test system

Test system:

human skin model

Source species:

other:

Cell type:

non-transformed keratinocytes

Cell source:

other: reconstructed human epidermal model EpiDermTM

Justification for test system used:

Initially the predictive capacity of the modified EpiDerm™ Skin Irritation Test (SIT) test method, using MatTek EpiDermTM tissue model EPI-200, underwent full prospective validation from 2003-2007. The test method components of this method were used to define the essential test methods components of the original and updated ECVAM Performance Standards (PS).
A modification of the original EpiDerm™ SIT was validated using the original ECVAM PS in 2008. In 2008, ESAC concluded that the Modified EpiDerm™ SIT has sufficient accuracy and reliability for prediction of R38 skin irritating and no-label (non-skin irritating) test substances.

Vehicle:

other:

Details on test system:

The reconstructed human epidermal model EpiDermTM (EPI-200-MatTek Corporation) consists of normal human-derived epidermal keratinocytes which have been cultured to form a multi-layered highly differentiated model of the human epidermis. It consists of organised basal, spinous and granular layers and a multi-layered stratum corneum containing intercellular lamellar lipid layers arranged in patterns analogous to those found in vivo.

Lot No.: 25819
Keratinocyte Strain: 00267

MatTek’s EpiDermTM model has been extensively characterised for multiple parameters including morphology, tissue viability, skin barrier function and sterility. QC results for the specific lot of models received (Lot# 25819) were checked in-house for MatTek acceptance ranges with the following outcome:
- Morphology - PASS
- Tissue viability - PASS
- Skin barrier function (ET50 value for 1% Triton X-100) where ET50 is the time taken for 1% Triton X-100 to reduce the viability of the skin model to 50% relative to the negative control)- PASS
- Sterility testing showed no contamination during long term antibiotic and antimycotic free culture- PASS

Control samples:

yes, concurrent negative control

yes, concurrent positive control

Amount/concentration applied:

Single topical application of 30 μL of neat test substance.

Duration of treatment / exposure:

60 minutes (25 minutes at room temperature and 35 minutes at 37°C, 5% CO2, 95% RH).

Duration of post-treatment incubation (if applicable):

42 hours

Number of replicates:

Three tissues per condition (n=3).

Results and discussion

In vitro

Results

Irritation / corrosion parameter:

% tissue viability

Run / experiment:

Mean

Value:

ca. 102.6

Vehicle controls validity:

valid

Negative controls validity:

not examined

Positive controls validity:

valid

Remarks on result:

no indication of irritation

Other effects / acceptance of results:

All validity criteria for the test were met:
- Criteria: the mean OD570 of the negative control (treated with DPBS) tissues is ≥ 0.8 and ≤ 2.8
Result for the test: 1.777

- The mean of the positive control relative percentage viability must be ≤ 20 % of the mean of the negative controls.
Result for the test: 3.8 %

- The standard deviation of OD values for triplicate skin models in each experimental condition must be < 18 %
Results for the test:
NC: 5 %
PC: 0.72 %
Test substance: 11.97%

Optical Density (OD) values obtained with blanks were higher than 0.1 (0.191) causing a deviation from acceptance criteria 4. However, the spectrophotometer was fully validated and had passed all required tests. The OD values for blanks observed in this study are consistent with historical data using this spectrophotometer in the XCellR8 laboratory and meet our current internal acceptance criteria of blank OD values <0.194 (mean of XCellR8 historical data, based on blanks obtained during the last 66 studies), therefore this is not considered to be an issue in the interpretation of this study data.
This SOP and guideline deviation was not considered to have affected the integrity or interpretation of the results as no equivocal results were obtained.

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Conclusions:

Under the study conditions, the test substance was considered to be non-irritating to skin.

Executive summary:

An in vitro study was conducted to determine the skin irritation and corrosion potential of the test substance using the Reconstituted Human Epidermis Test Method according to OECD Guideline 439, in compliance with GLP.

 

The substance was incubated (in triplicate) with reconstructed human epidermal model EpiDerm™ for 1 hour (25 minutes at room temperature and 35 minutes at 37°C, 5% CO2, 95% RH) as a single topical application (30 µL) with the neat test substance. The test material was removed and incubated for a further 42 hours. At the end of the incubation period, the viability of the cells was determined by measuring the enzymatic conversion of the vital dye MTT (3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide; Thiazolyl blue tetrazolium bromide). The opticl density was determined using a Spectrophotometer (wavelength 570 nm). Although Optical Density (OD) values obtained with blanks were higher than 0.1 (0.191) causing a deviation from acceptance criteria 4. However, the spectrophotometer was fully validated and had passed all required tests. The OD values for blanks observed in this study are consistent with historical data using this spectrophotometer in the XCellR8 laboratory and meet our current internal acceptance criteria of blank OD values <0.194 (mean of XCellR8 historical data, based on blanks obtained during the last 66 studies), therefore this is not considered to be an issue in the interpretation of this study data.

This SOP and guideline deviation was not considered to have affected the integrity or interpretation of the results as no equivocal results were obtained.

The mean tissue viability of the treated tissues was determined to be 102.6 %, indicated no irritation under the conditions of the test.