Dioctyl maleate, branched

Skin irritation / corrosion

Administrative data

Endpoint:

skin corrosion: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

25 October 2017 - 26 October 2017

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2018

Report date:

2018

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Dioctyl maleate, branched

EC Number:

287-673-6

EC Name:

Dioctyl maleate, branched

Cas Number:

85566-63-8

Molecular formula:

C20H36O4

IUPAC Name:

1,4-bis(octan-2-yl) (2Z)-but-2-enedioate

Specific details on test material used for the study:

Test Article: Bernel Ester DCM
CAS Number: 85566-63-8
Storage: 15 to 25˚C, protected from light
Purity: 92.78%

In vitro test system

Test system:

human skin model

Source species:

human

Cell type:

non-transformed keratinocytes

Cell source:

other: Three-dimensional human skin model, comprising a reconstructed epidermis with a functional stratum corneum supplied by MatTek In Vitro Life Science Laboratories, Bratislava, Slovak Republic.

Justification for test system used:

This study was conducted to determine whether the test article causes corrosion in the in vitro skin model EpiDermTM.
The test article was applied topically to a three-dimensional human skin model, comprising a reconstructed epidermis with a functional stratum corneum. Corrosive materials are identified by their ability to produce a decrease in cell viability (as determined using the MTT reduction assay) below defined thresholds at specified exposure periods. The principle of the human skin model assay is based on the hypothesis that corrosive chemicals are able to penetrate the stratum corneum by diffusion or erosion, and are cytotoxic to the underlying cell layers.

Vehicle:

unchanged (no vehicle)

Details on test system:

Test System
Specifications
Three-dimensional human skin model, comprising a reconstructed epidermis with a functional stratum corneum supplied by MatTek In Vitro Life Science Laboratories, Bratislava, Slovak Republic.

Identification
The test system was appropriately labelled with the study number, date of treatment, duration of treatment and negative/positive/test article.

General Model Conditions
Human keratinocytes are used to construct the epithelium. Multiple layers of viable epithelial cells are present under a functional stratum corneum. The stratum corneum is multi-layered with the necessary lipid profile to produce a functional barrier. The containment properties of the model prevent the passage of material around the stratum corneum to the viable model tissue. The skin model was supplied free of contamination with bacteria, mycoplasma and fungi.

Functional Model Conditions
The magnitude of viability is quantified using MTT. The optical density (OD) of the extracted (solubilised) dye from the negative control tissue is at least 20-fold greater than the OD of the extraction solvent alone. The negative control tissue has been shown to be stable in culture for the duration of the test exposure period. The stratum corneum is sufficiently robust to resist the rapid penetration of certain cytotoxic marker chemicals (eg 1% Triton X-100). This property has been estimated by the exposure time required to reduce cell viability by 50% (ET50). For the EpiDermTM model the lower acceptance limit is 4.08 hours and the upper acceptance limit is 8.7 hours. The tissue has been shown to demonstrate reproducibility over time, and it has been shown to be capable of predicting the corrosive potential of the reference chemicals when using the testing protocol selected.

Control samples:

yes, concurrent negative control

Amount/concentration applied:

50 µL

Duration of treatment / exposure:

3 minute and 60 minutes

Duration of post-treatment incubation (if applicable):

3 hours

Number of replicates:

4

Results and discussion

In vitro

Results

Results 1

Irritation / corrosion parameter:

% tissue viability

Run / experiment:

3 minutes exposure

Value:

98

Negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

no indication of irritation

Results 2

Irritation / corrosion parameter:

% tissue viability

Run / experiment:

60 minutes exposure

Value:

93

Negative controls validity:

valid

Positive controls validity:

valid

Other effects / acceptance of results:

The OD values for the negative controls met the acceptance criteria.
Skin viability after a 3 minute or 60 minute exposure to the positive control article was 2% and 4%, respectively, demonstrating appropriate performance of the assay.

Any other information on results incl. tables

3 minute exposure period

Test Substance	OD570			Mean	Tissue Mean	Tissue Mean - FK	%Survival	%CV
Negative	0.968	0.981	0.969	0.973	1.029		100	6.1
Negative	1.066	1.105	1.082	1.084
Test article	1.021	1.031	1.017	1.023	1.009		98	1.8
Test article	0.982	1.005	0.997	0.995
Positive	0.192	0.191	0.189	0.191	0.175	0.018	2	9.6
Positive	0.16	0.162	0.158	0.16
Positive FK	0.131	0.132	0.13	0.131	0.158
Positive FK	0.183	0.186	0.184	0.184

60 minute exposure period

Test Substance	OD570			Mean	Tissue Mean	Tissue Mean - FK	%Survival	%CV
Negative	1.174	1.19	1.168	1.177	1.166		100	1.7
Negative	1.156	1.133	1.172	1.154
Test article	1.102	1.047	1.103	1.084	1.082		93	2
Test article	1.08	1.091	1.068	1.079
Positive	0.308	0.296	0.31	0.305	0.259	0.05	4	20
Positive	0.202	0.236	0.202	0.213
Positive FK	0.211	0.25	0.217	0.226	0.21
Positive FK	0.193	0.191	0.197	0.194

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Conclusions:

The test article, Bernal Ester DCM, was considered to be non-corrosive according to the UN GHS classification system.

Executive summary:

This study was conducted to determine whether the test article, Bernel Ester DCM, causes corrosion in the in vitro skin model EpiDerm^TM.

Duplicate EpiDerm^TM inserts were treated with test article, purified water (negative control) and 8N potassium hydroxide (positive control) for 3 minutes and 60 minutes. At the end of the treatment period, the tissues were washed with phosphate buffered saline (PBS) and cell viability was assessed using the MTT assay. The skin corrosivity potential was classified according to the remaining cell viability obtained after test material treatment with either of the two treatment times.

Skin viability after a 3 minute or 60 minute exposure to the test article was 98% and 93%, respectively.

The OD values for the negative controls met the acceptance criteria.

Skin viability after a 3 minute or 60 minute exposure to the positive control article was 2% and 4%, respectively, demonstrating appropriate performance of the assay.

The test article, Bernal Ester DCM, was considered to be non-corrosive according to the UN GHS classification system.