Fatty acids, C16-18 and C18-unsatd., mixed esters with adipic acid and trimethylolpropane

Skin irritation / corrosion

Administrative data

Endpoint:

skin irritation: in vitro / ex vivo

Type of information:

migrated information: read-across based on grouping of substances (category approach)

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

GLP - Guideline study. According to the ECHA guidance document "Practical guide 6: How to report read-across and categories (March 2010)", the reliability was changed from RL1 to RL2 to reflect the fact that this study was conducted on a read-across substance.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2012

Report date:

2012

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

other: OECD guideline 431 (In vitro skin corrosion: Human skin model test) adopted 2004

Deviations:

no

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

921-836-0

EC Number:

921-836-0

IUPAC Name:

921-836-0

Details on test material:

- Name of test material (as cited in study report): [trade name]
- Composition: mixed ester of fatty acids, C 16 and C 16-18 unsaturated with adipic acid and pentaerithrytol
- Physical state/appearance: yellow liquid
- Analytical purity: no data
- Batch No.: 103991

Test animals

Species:

other: not applicable (in vitro test)

Strain:

other: not applicable (in vitro test)

Details on test animals or test system and environmental conditions:

TEST SYSTEM
The test substance was applied topically on SkinEthic RHE tissues, a 3D system of reconstructed epidermis of normal human keratinocytes with a functional stratum corneum. Cells are grown on inert polycarbonate filter on chemically defined medium, airlifted for 17 days. The model exhibits normal barrier functions (presence of a differentiated stratum corneum).
- Supplier of SkinEthic RHE tissue, maintenance medium (SMM) and growth medium (SGM): SkinEthic

Test system

Type of coverage:

other: not applicable (in vitro test)

Preparation of test site:

other: not applicable (in vitro test)

Vehicle:

other: PBS

Controls:

other: not applicable (in vitro test); negative (water) and positive (glacial acetic acid) control were included

Amount / concentration applied:

40 ± 0.5 µL

Duration of treatment / exposure:

3 minutes and 1 hours at 37 °C

Observation period:

not applicable (in vitro test)

Number of animals:

not applicable (in vitro test)

Details on study design:

PRE-TEST
The test product was put in contact with MTT (thiazolyl blue tetrazolium) solution to detect non-specific reduction of MTT. 40 µL of sample were incubated for 3 hours at 37 °C with 300 µL of MTT ready to use, water was used as negative control. At the end of this period a visual observation was performed and interpreted according to the following criteria:
Yellow: no interaction; light blue: slight interaction; dark blue: strong interaction
If the MTT solution becomes blue or purple the sample interact with MTT and is necessary to evaluate the part of optical density due to a non-specific reduction of the MTT.

MAIN TEST
The test product, the negative and positive control were applied in duplicate on the tissues for 3 minutes and 1 hour at room temperature.
At the end of the exposure time the product and the controls were removed from the tissues and the tissues rinsed for 5 times with PBS.
After the post treatment the tissues were treated for 3 hours at 37 °C, 5% Co2 with MTT ready to use and then put in contact with 1.5 mL of isopropanol for 2 hours at room temperature with gentle agitation for formazan extraction.

Results and discussion

In vivo

Irritant / corrosive response data:

- Cell viability after 3 min treatment: 88.98%
- Cell viability after 1 h treatment: 88.5%

Any other information on results incl. tables

Table 1: Individual values: optic density (OD) at 570 nm; 3 minutes treatment

3 min	1	2	3	4	5	6	Mean	%Viability
Blank	0.086	0.087	0.091	0.089	0.088	0.088	0.088	-
Negative control	1.255	1.269	1.266	1.266	1.266	1.271	1.266	100%
Positive control	0.095	0.093	0.094	0.096	0.095	0.096	0.095	0.59%
Sample	1.121	1.141	1.139	1.147	1.133	1.145	1.138	88.98%

 

Table 2: Individual values: optic density (OD) at 570 nm; 1 hour treatment

1 h	1	2	3	4	5	6	Mean	%Viability
Blank	0.087	0.087	0.088	0.092	0.087	0.086	0.088	-
Negative control	1.297	1.275	1.281	1.280	1.293	1.279	1.284	100%
Positive control	0.093	0.091	0.093	0.094	0.093	0.092	0.093	0.42%
Sample	1.152	1.155	1.151	1.144	1.155	1.142	1.150	88.5%

Applicant's summary and conclusion

Interpretation of results:

other: not corrosive

Remarks:

Criteria used for interpretation of results: EU

Conclusions:

There is regulatory acceptance in the EU that a substance can be considered corrosive based on a positive result in one of the available in vitro test methods, e.g. the human skin model (HSM) test (OECD 431). Negative in vitro corrosivity responses are not conclusive with respect to non-classification or classification as irritant (Category 2/R37) and shall therefore be subject to further evaluation.