Octadecyl docosanoate

Skin irritation / corrosion

Administrative data

Endpoint:

skin corrosion: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

10 - 11 Aug 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

Test guideline 1

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

adopted in 2016

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

other: EU method B.40 BIS. (In Vitro Skin Corrosion: Human Skin Model Test)

Version / remarks:

adopted in 2008

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Remarks:

Bayrisches Landesamt für Gesundheit und Lebensmittelsicherheit, Schwabach, Germany

Test material

Test material information

Constituent 1

Reference substance name:

Octadecyl docosanoate

EC Number:

246-115-1

EC Name:

Octadecyl docosanoate

Cas Number:

24271-12-3

Molecular formula:

C40H80O2

IUPAC Name:

octadecyl docosanoate

In vitro test system

Test system:

human skin model

Source species:

human

Cell type:

non-transformed keratinocytes

Source strain:

other: EpiDerm™ (keratinocyte strain: 00267)

Justification for test system used:

This test uses the EpiDerm™ Skin Model is a well established organotypic, three-dimensional model of the human epidermis and is used for in vitro experiments since many years. It is known for its similarity to human skin.

Vehicle:

water

Details on test system:

RECONSTRUCTED HUMAN EPIDERMIS (RHE) TISSUE
- Model used: EpiDerm™ Kit (Epi-200, MatTek In vitro Life Science Laboratories (Bratislava, Slovakia)
- Tissue batch number(s): 25835

TEMPERATURE USED FOR TEST SYSTEM
- Temperature used during treatment / exposure: 37 ± 1 °C (for both exposures)

REMOVAL OF TEST MATERIAL AND CONTROLS
-Volume and number of washing steps: rinsed about 20 times with DPBS

MTT DYE USED TO MEASURE TISSUE VIABILITY AFTER TREATMENT / EXPOSURE
- MTT concentration: 1 mg/mL
- Incubation time: 3 h
- Spectrophotometer: plate spectrophotometer
- Wavelength: 570 nm

FUNCTIONAL MODEL CONDITIONS WITH REFERENCE TO HISTORICAL DATA
- Viability: OD = 1.474 ± 0.093 (acceptance range. 1.0 - 3.0)
- Barrier function: ET-50: 5.93 h (acceptance range: 4.77 - 8.72 h)
- Morphology: functional stratum corneum, a viable basal cell layer and an intermediate spinous and granular layers
- Contamination: no

NUMBER OF REPLICATE TISSUES: 2

CONTROL TISSUES USED IN CASE OF MTT DIRECT INTERFERENCE
No MTT interference of the test item.

NUMBER OF INDEPENDENT TEST SEQUENCES / EXPERIMENTS TO DERIVE FINAL PREDICTION: 1

PREDICTION MODEL / DECISION CRITERIA
- The test substance is considered to be corrosive to skin if the viability after 3 minutes exposure is less than 50%. A viability after 3 minutes exposure of greater than or equal to 50 % and the viability after 1 hour exposure of less than 15% is considered to be corrosive (combination of optional sub-categories 1B and 1C).
Subcategorisation (optional): A viability after 3 minutes exposure of less than 25% will lead to subcategory 1A. A viability after 3 minutes exposure of greater than or equal to 25% will lead to sub-categories 1B and 1C.
- The test substance is considered to be non-corrosive to skin if the viability after 3 minutes exposure is greater than or equal to 50% and the viability after 1 hour exposure is greater than or equal to 15%.

Control samples:

yes, concurrent vehicle

yes, concurrent positive control

Amount/concentration applied:

TEST MATERIAL
- Amount(s) applied: 25 mg + 25 μL H2O

VEHICLE
- Amount(s) applied: 50 μL

POSITIVE CONTROL
- Amount(s) applied: 50 μL
- Concentration: 8 N

Duration of treatment / exposure:

3 min and 60 min

Number of replicates:

2

Results and discussion

In vitro

Results

Results 1

Irritation / corrosion parameter:

% tissue viability

Remarks:

(mean value)

Run / experiment:

test substance, 3 min exposure

Value:

92.5

Vehicle controls validity:

valid

Negative controls validity:

not examined

Positive controls validity:

valid

Remarks on result:

no indication of irritation

Results 2

Irritation / corrosion parameter:

% tissue viability

Remarks:

(mean value)

Run / experiment:

test substance, 60 min exposure

Value:

105.3

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:

DEMONSTRATION OF TECHNICAL PROFICIENCY: not reported

ACCEPTANCE OF RESULTS:
- Acceptance criteria met for negative control: yes, as the mean OD 570 (3 min exposure) = 1.724 and the mean OD 570 (60 min exposure) = 1.767 (acceptance range for both exposure times: mean OD 570 = 0.8 - 2.8)
- Acceptance criteria met for positive control: yes, as the mean relative tissue viability (%) of PC after 60 min exposure: 8.9 % (acceptance range: mean relative tissue viability <15 %)
- Acceptance criteria met for variability between replicate measurements: yes as the coefficients of variation were between 2.3 and 7.8% (acceptance criteria ≤ 30%)

Any other information on results incl. tables

Table 1: Results after 3 min exposure for the test substance, positive and negative controls.

	Negative control		Positive control		Test item
Tissue sample	1	2	1	2	1	2
OD570 (blank corrected)	1.619	1.803	0.223	0.205	1.568	1.653
	1.633	1.800	0.233	0.207	1.557	1.629
	1.634	1.857	0.231	0.205	1.540	1.627
OD570 (mean) ± SD	1.629 ± 0.008	1.820 ± 0.038	0.229 ± 0.025	0.205 ± 0.025	1.555 ± 0.028	1.636 ± 0.028
OD570 (mean values of replicates) ± SD	1.724 ± 0.135		0.217 ± 0.017		1.596 ± 0.057
Relative viability (%)	100.0		12.6		92.5
CV (%)	7.8		7.7		3.6

CV = coefficient of variation

SD = standard deviation

Table 2: Results after 60 min exposure for the test substance, positive and negative controls.

	Negative control		Positive control		Test item
Tissue sample	1	2	1	2	1	2
OD570 (blank corrected)	1.63	1.866	0.145	0.167	1.859	1.909
	1.712	1.855	0.153	0.162	1.82	1.862
	1.686	1.854	0.154	0.163	1.810	1.902
OD570 (mean) ± SD	1.676 ± 0.042	1.859 ± 0.025	0.151 ± 0.025	0.164 ± 0.025	1.830 ± 0.034	1.891 ± 0.034
OD570 (mean values of replicates) ± SD	1.767 ± 0.129		0.157 ± 0.009		1.860 ± 0.043
Relative viability (%)	100.0		8.9		105.3
CV (%)	7.3		5.9		2.3

CV = coefficient of variation

SD = standard deviation

Applicant's summary and conclusion

Interpretation of results:

other: non-corrosive (Skin Irrit. 2 or not classified according to Regulation (EC) No 1272/2008

Conclusions:

Under the conditions of the test, the test substance was shown to have no corrosive potential towards reconstructed human epidermis tissue in the Epiderm™ skin model. The result does not allow for the non-classification or classification as irritant of the test substance and therefore further evaluation and/or data generation is required.