2-[(octadecylcarbamoyl)oxy]ethyl acrylate

Endpoint summary

Description of key information

Skin Irritation

In an in vitro OECD 439 study, under GLP conditions, using EPISKIN™ Reconstructed Human Epidermis Model 2-Propenoic acid, 2-[[(octadecylamino)carbonyl]oxy]ethyl ester is considered not irritating to skin (Envigo, 2016h).

Skin Corrosion

In an in vitro OECD 431 study, under GLP conditions, using EpiDerm™ Human Skin Model 2-Propenoic acid, 2-[[(octadecylamino)carbonyl]oxy]ethyl ester is considered not corrosive to skin (Envigo, 2016j).

 

Eye Irritation

In an in vitro OECD 437 study, under GLP conditions, using Bovine Cornea 2-Propenoic acid, 2-[[(octadecylamino)carbonyl]oxy]ethyl ester is considered not irritating to eyes (Envigo, 2016i).

Key value for chemical safety assessment

Skin irritation / corrosion

Link to relevant study records

Reference

Reference 1

Endpoint:

skin irritation: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2016

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

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

Deviations:

yes

Remarks:

please see principles of method if other than guideline for details on deviations.

Principles of method if other than guideline:

The standard deviation of the relative individual viabilities for the three test item treated tissues was 19.5% which was slightly higher than the assay acceptance criterion of 18%. However, as all three tissues gave an unequivocal negative result it was deemed unnecessary to repeat the test.

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

Identification: 2-Propenoic acid, 2-[[(octadecylamino)carbonyl]oxy]ethyl ester
Purity: >98%
Physical state/Appearance: White solid
Expiry Date: 20 June 2017
Storage Conditions: Room temperature in the dark

Test system:

human skin model

Source species:

human

Cell type:

non-transformed keratinocytes

Vehicle:

unchanged (no vehicle)

Details on test system:

Main Test
Application of Test Item and Rinsing (Day 1)
2 mL of maintenance medium, warmed to approximately 37C, was pipetted into the second column of 3 wells of the 12 well plate.

Triplicate tissues were treated with the test item for an exposure period of 15 minutes. The test item was applied topically to the corresponding tissues ensuring uniform covering. 5 µL of sterile distilled water was topically applied to the epidermal surface in order to improve contact between the test item and the epidermis. Approximately 10 mg (26.3 mg/cm2) of the test item was then applied to the epidermal surface. Triplicate tissues treated with 10 µL of DPBS served as the negative controls and triplicate tissues treated with 10 µL of SDS 5% w/v served as the positive controls. To ensure satisfactory contact with the positive control item the SDS solution was spread over the entire surface of the epidermis using a pipette tip (taking particular care to cover the center). After a 7 Minute contact time the SDS solution was re spread with a pipette tip to maintain the distribution of the SDS for the remainder of the contact period (re-spreading is not required for the negative control or test item). The plates were kept in the biological safety cabinet at room temperature for 15 minutes.

At the end of the exposure period, each tissue was removed from the well using forceps and rinsed using a wash bottle containing DPBS with Ca++ and Mg++. Rinsing was achieved by filling and emptying each tissue insert for approximately 40 seconds using a constant soft stream of DPBS to gently remove any residual test item. The rinsed tissues were transferred to the second column of 3 wells containing 2 mL of maintenance medium in each well. The rinsed tissues were incubated at 37C, 5% CO2 in air for 42 hours.

MTT Loading/Formazan Extraction (Day 3)
Following the 42 Hour post-exposure incubation period each 12-well plate was placed onto a plate shaker for 15 minutes to homogenize the released mediators in the maintenance medium. 1.6 mL of the maintenance medium from beneath each tissue was transferred to pre labeled micro tubes and stored in a freezer at 14 to 30 ºC for possible inflammatory mediator determination.
2 mL of a 0.3 mg/mL MTT solution, freshly prepared in assay medium, was pipetted into the third column of 3 wells of the 12-well plates. The tissues were transferred to the MTT filled wells, being careful to remove any excess maintenance medium from the bottom of the tissue insert by blotting on absorbent paper. The tissues were incubated for 3 hours at 37 °C, 5% CO2 in air. At the end of the 3 Hour incubation period each tissue was placed onto absorbent paper to dry. A total biopsy of the epidermis was made using the EPISKINTM biopsy punch. The epidermis was carefully separated from the collagen matrix using forceps and both parts (epidermis and collagen matrix) placed into labeled 1.5 mL micro tubes containing 500 µL of acidified isopropanol, ensuring that both the epidermis and collagen matrix were fully immersed. Each tube was plugged to prevent evaporation and mixed thoroughly on a vortex mixer. The tubes were refrigerated at 1 to 10 °C until Day 6 of the experiment, allowing the extraction of formazan crystals out of the MTT-loaded tissues.

Absorbance/Optical Density Measurements (Day 6)
At the end of the formazan extraction period each tube was mixed thoroughly on a vortex mixer to produce a homogenous colored solution.

For each tissue, duplicate 200 µL samples were transferred to the appropriate wells of a pre labeled 96 well plate. 200 µL of acidified isopropanol alone was added to the two wells designated as ‘blanks’. The optical density was measured (quantitative viability analysis) at 562 nm (without a reference filter) using the Anthos 2001 microplate reader.

Control samples:

yes, concurrent negative control

yes, concurrent positive control

Amount/concentration applied:

Approximately 10 mg (26.3 mg/cm2) of the test item was then applied to the epidermal surface.

Duration of treatment / exposure:

15 minutes

Irritation / corrosion parameter:

% tissue viability

Value:

83.6

Negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

no indication of irritation

Direct MTT Reduction

The MTT solution containing the test item did not turn blue or purple which indicated that the test item did not directly reduce MTT. 

Assessment of Color Interference with the MTT endpoint

The solution containing the test item was a white color. This color was attributed to the intrinsic color of the test item itself. It was therefore unnecessary to run color correction tissues.

Interpretation of results:

GHS criteria not met

Conclusions:

The test item was classified as non-irritant.

Reference 2

Endpoint:

skin corrosion: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

2016

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 431 (In Vitro Skin Corrosion: Reconstructed Human Epidermis (RHE) Test Method)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

Identification: 2-Propenoic acid, 2-[[(octadecylamino)carbonyl]oxy]ethyl ester
Physical state/Appearance: White solid
Purity: >98%
Storage Conditions: Room temperature in the dark

Test system:

human skin model

Remarks:

EpiDerm™

Source species:

human

Details on test system:

Pre-Incubation
The assay medium was pre-warmed before use. 0.9 mL of this assay medium was pipetted into the appropriate wells of two pre-labeled 6-well plates for both the 3 Minute and 60 Minute exposure periods. EpiDerm™ tissues were transferred into the 6 well plates containing the assay medium. The 6 well plates containing the EpiDerm™ samples were pre-incubated (37 °C, 5% CO2) for approximately 1 hour before dosing.

Application of Test Item and Rinsing
Before pre-incubation was complete, a 24 well plate was prepared for use as a “holding plate” for both the 3 Minute and 60 Minute exposure periods. This plate was used to maintain the viability of the tissue inserts between rinsing following chemical exposure and MTT loading. Another 24 well plate was prepared for the MTT loading. 300 µL of either pre warmed assay medium (holding plate) or MTT medium (MTT loading plate) was dispensed into each well. The two plates were placed into the incubator until required.

After pre incubation of the EpiDerm™ tissues, the medium was aspirated and replaced with 0.9 mL of fresh assay medium. The 6-well plate for the 3 Minute exposure period was returned to the incubator, while the other was being dosed for the 60 Minute exposure. For the 60 Minute exposure period, 50 µL of sterile distilled water (negative control) was added to the first two tissues. The tissues were dosed at regular intervals to allow for the time taken to rinse each tissue following exposure and to ensure that each tissue gets an equal exposure time. 25 mg of the test item and 50 µL of 8.0 N Potassium Hydroxide (positive control) were also applied to the corresponding tissues in turn. 25 µL of sterile water was added for wetting of the test item to increase tissue surface contact. The plate was returned to the incubator (37 °C, 5% CO2) for the 60 Minute exposure period.

When dosing for the 60 Minute exposure period was complete, the same procedure was repeated for the 3 Minute exposure period. Because the exposure time was so short, the tissues were dosed at regular intervals to ensure that each tissue received an equal exposure time and to allow for the time taken to rinse each tissue following exposure. Rinsing was achieved by filling and emptying each tissue under a constant soft stream of DPBS to gently remove any residual test item. Excess DPBS was removed by blotting the bottom of the tissue insert with tissue paper. Each tissue was placed into the prepared holding plate until all tissues were rinsed. They were then blotted and transferred to the 24 well plate prepared for MTT loading. The plate was incubated (37 °C, 5% CO2) for 3 hours. Once the 60 Minute exposure period was complete, the same rinsing and MTT loading procedure was repeated.

After the 3 Hour MTT incubation was complete, the inserts were blotted and transferred to labeled 24 well plates for MTT extraction. 2 mL of MTT extractant (isopropanol) was used to completely immerse each insert and the plate was covered with plate sealer to prevent Isopropanol evaporation. The plates stood overnight at room temperature, to allow extraction to proceed.

Absorbance/Optical Density Measurements
After extraction, each tissue was pierced with a pipette fitted with a 1000 µL tip and the extraction solution was forced vigorously up and down to form a homogenous solution. 3 x 200 µL aliquots of the extract were transferred to the appropriate wells of a pre labeled 96 well plate. 200 µL of isopropanol alone was added to the three wells designated as blanks. Absorbency at 562nm (OD562) of each well was measured using the Anthos 2001 microplate reader.

Control samples:

yes, concurrent negative control

yes, concurrent positive control

Duration of treatment / exposure:

3 minutes and 60 minutes.

Irritation / corrosion parameter:

% tissue viability

Run / experiment:

3 minute

Value:

98

Remarks on result:

other:

Remarks:

Not corrosive

Irritation / corrosion parameter:

% tissue viability

Run / experiment:

6 minute

Value:

102

Remarks on result:

other:

Remarks:

Not corrosive

Direct MTT Reduction

The MTT solution containing the test item did not turn blue/purple. This was taken to indicate the test item did not reduce MTT.

Assessment of Color Interference with the MTT endpoint

The solution containing the test item did not become colored. This was taken to indicate the test item did not have the potential to cause color interference.

The mean OD₅₆₂for the negative control treated tissues was 1.791 for the 3‑Minute exposure period and 1.839 for the 60‑Minute exposure period. The negative control acceptance criteria were therefore satisfied.

The relative mean tissue viability for the positive control treated tissues was 3.7% relative to the negative control following the 60‑Minute exposure period. The positive control acceptance criterion was therefore satisfied.

In the range 20 to 100% viability the Coefficient of Variation between the two tissue replicates of each treatment group did not exceed 30%. The acceptance criterion was therefore satisfied.

Interpretation of results:

GHS criteria not met

Conclusions:

The test item was considered to be non-corrosive to the skin.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Eye irritation

Link to relevant study records

Reference

Endpoint:

eye irritation: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2016

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 437 (Bovine Corneal Opacity and Permeability Test Method for Identifying Ocular Corrosives and Severe Irritants)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

Identification: 2-Propenoic acid, 2-[[(octadecylamino)carbonyl]oxy]ethyl ester
Physical state/Appearance: white solid
Purity: >98%
Storage Conditions: room temperature in the dark

Species:

cattle

Details on test animals or tissues and environmental conditions:

All eyes were macroscopically examined before and after dissection. Only corneas free of damage were used.

The cornea from each selected eye was removed leaving a 2 to 3 mm rim of sclera to facilitate handling. The iris and lens were peeled away from the cornea. The isolated corneas were immersed in a dish containing HBSS until they were mounted in Bovine Corneal Opacity and Permeability (BCOP) holders.

The anterior and posterior chambers of each BCOP holder were filled with complete Eagle’s Minimum Essential Medium (EMEM) without phenol red and plugged. The holders were incubated at 32 ± 1 ºC for 80 minutes. At the end of the incubation period each cornea was examined for defects

Three corneas with opacity values close to the median value of all corneas were allocated to the negative control. Three corneas were also allocated to the test item and three corneas to the positive control item.

Vehicle:

unchanged (no vehicle)

Controls:

yes, concurrent positive control

yes, concurrent negative control

Amount / concentration applied:

0.75 mL of the test item preparation or control items were applied to the appropriate corneas

Duration of treatment / exposure:

240 minutes.

Details on study design:

The EMEM was removed from the anterior chamber of the BCOP holder and 0.75 mL of the test item preparation or control items were applied to the appropriate corneas. The holders were gently tilted back and forth to ensure a uniform application of the item over the entire cornea. Each holder was incubated, anterior chamber uppermost, at 32 ± 1 ºC for 240 minutes.

At the end of the exposure period the test item and control items were removed from the anterior chamber and the cornea was rinsed three times with fresh complete EMEM containing phenol red before a final rinse with complete EMEM without phenol red. The anterior chamber was refilled with fresh complete EMEM without phenol red. A post-treatment opacity reading was taken and each cornea was visually observed.

Following the opacity measurement the permeability of the corneas to sodium fluorescein was evaluated. The medium from the anterior chamber was removed and replaced with 1 mL of sodium fluorescein solution (5 mg/mL). The dosing holes were plugged and the holders incubated, anterior chamber uppermost, at 32 ± 1 ºC for 90 minutes.

After incubation the medium in the posterior chamber of each holder was decanted and retained.
360 µL of medium representing each cornea was applied to a designated well on a 96 well plate and the optical density at 492 nm (OD492) was measured using the Anthos 2001 microplate reader.

The corneas were retained after testing for possible conduct of histopathology. Each cornea was placed into a pre labeled tissue cassette fitted with a histology sponge to protect the endothelial surface. The cassette was immersed in 10% neutral buffered formalin.

The corrected OD492 was calculated by subtracting the mean OD492 of the negative control corneas from the OD492 value of each treated cornea. The OD492 value of each treatment group was calculated by averaging the corrected OD492 values of the treated corneas for the treatment group.

The following formula was used to determine the In Vitro Irritancy Score:

In Vitro Irritancy Score = mean opacity value + (15 x mean permeability OD492 value)

Additionally, the opacity and permeability values were evaluated independently to determine whether the test item induced a response through only one of the two endpoints.

Irritation parameter:

in vitro irritation score

Value:

0.2

Vehicle controls validity:

not applicable

Negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

no indication of irritation

Other effects / acceptance of results:

The corneas treated with the test item were clear post treatment. The corneas treated with the negative control item were clear post treatment. The corneas treated with the positive control item were cloudy post treatment.

The positive control In Vitro Irritancy Score was within the range of 66.9 to 101.4. The positive control acceptance criterion was therefore satisfied.

The negative control gave opacity of ≤4.1 and permeability ≤0.105. The negative control acceptance criteria were therefore satisfied.

Interpretation of results:

GHS criteria not met

Conclusions:

The test item received an In Vitro Irritancy Score of 0.2, and is classified as ‘No category. Not requiring classification to UN GHS or EU CLP’.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Justification for classification or non-classification

Skin irritation / corrosion:

Skin Irritation

In an in vitro OECD 439 study, under GLP conditions, using EPISKIN™ Reconstructed Human Epidermis Model 2-Propenoic acid, 2-[[(octadecylamino)carbonyl]oxy]ethyl ester is considered not irritating to skin (Envigo, 2016h).

 

Skin Corrosion

In an in vitro OECD 431 study, under GLP conditions, using EpiDerm™ Human Skin Model 2-Propenoic acid, 2-[[(octadecylamino)carbonyl]oxy]ethyl ester is considered not corrosive to skin (Envigo, 2016j).

 

According to the ECHA Guidance on the Application of the CLP Criteria (version 4.1, June 2015), an in vitro skin irritation and corrosion study can be used to classify a substance as a skin irritant if the result is positive. Negative results do not necessarily confirm no classification, therefore additional in vitro or in vivo testing may be required.

2-Propenoic acid, 2-[[(octadecylamino)carbonyl]oxy]ethyl ester is considered not irritating or corrosive to the eye according to in vitro testing methods, therefore, is not classified as a skin irritant or skin corrosive, however, further testing may be required at the next tonnage band.