DODECANEDIOIC ACID, 1,12-BIS(2-OCTYLDODECYL) ESTER

Skin irritation / corrosion

Administrative data

Endpoint:

skin irritation: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2014

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study with acceptable restrictions

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2014

Report date:

2014

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

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

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

1

Reference substance name:

1,12-bis(2-octyldodecyl) dodecanedioate

EC Number:

603-333-5

Cas Number:

129423-55-8

Molecular formula:

C52 H102 O4

IUPAC Name:

1,12-bis(2-octyldodecyl) dodecanedioate

Details on test material:

Test Substance Name: Dioctyldodecyl Dodecanedioate
CAS number: 129423-55-8
Batch number: P-4696
Purity: 100%
Receipt Date: 22 November 2019
Retest date: 23 September 2020
Storage on Receipt: Room Temperature (15 – 25°C)

In vitro test system

Test system:

human skin model

Remarks:

MatTek EpiDerm

Source species:

human

Cell type:

non-transformed keratinocytes

Cell source:

other: Cultured

Source strain:

other: Human (NHEK)

Vehicle:

unchanged (no vehicle)

Details on test system:

"MatTek's patented EpiDerm Skin Model consists of normal, human-derived epidermal keratinocytes (NHEK) which have been cultured to form a multilayered, highly differentiated model of the human epidermis. Keratinocytes are cultured on specially prepared, permeable cell culture inserts ... " This system " ... closely parallels human skin. EpiDerm consists of highly organized basal, spinous, granular and comified layers analogous to those found in vivo. Epiderm cultured keratinocytes are mitotically and metabolically active."

EpiDerm, when used with the recommended cell metabolism assay, can quickly provide toxicological profiles. The procedure utilizes a water-soluble, yellow, tetrazolium salt (MTT {3- [4,5-dimethylthiazol-2-yl]-2,5-diphenyl-tetrazolium bromide}), which is reduced by succinate dehydrogenase in the mitochondria of viable cells to a purple, insoluble formazan derivative. Substances which damage this mitochondrial enzyme inhibit the reduction of the tetrazolium salt. The amount of MTT reduced by a culture is therefore proportional to the number of viable cells.

After appropriate tissue preparation, one-hundred microliters of the liquid test article, at 100%, the reference article and the negative control (distilled water) were added to the Millicells containing the EpiDerm samples. The six (6) well plates containing the dosed EpiDerm samples were then incubated at 37°C, five (5)% carbon dioxide and >= 90% humidity. After the appropriate exposure periods, each insert was individually removed from its plate and rinsed with phosphate buffered saline (PBS) to remove any residual material. Each was then rinsed a second time. Excess liquid was shaken off and each EpiDerm sample was placed into 300 microliters of MTT solution. The EpiDerm samples were then returned to the incubator.


After the three (3) hour MTT exposure, each insert was removed and gently rinsed with PBS to remove any residual MTT solution. Excess PBS was shaken from each of the inserts, which were then blotted on the bottom using paper towels. The inserts were then each placed into one (1) well of a 24 well extraction plate. Each insert was then immersed in two (2) milliliters of extraction solution overnight. After the exposure, the liquid within each insert was decanted back into the well from which it was taken. The remaining extractant solution was then agitated and a 200 microliter aliquot of each extract was removed for evaluation. A Dynatech MR 4000 Automatic Microplate Reader was used to determine the absorbance of each extract at 570nm. With the absorbance of the negative control defined as 100%, the percent absorbencies of the test and reference articles were determined. The percentages listed in the results section directly correlate with the cell metabolism in the EpiDerm samples.

Control samples:

yes, concurrent negative control

other:

Amount/concentration applied:

100% 100 microliters

Duration of treatment / exposure:

1 hour, 4.5 hours, 20 hours

Duration of post-treatment incubation (if applicable):

3 hours

Number of replicates:

1

Test system

Controls:

yes, concurrent positive control

yes, concurrent negative control

Results and discussion

In vitro

Results

Results 1

Irritation / corrosion parameter:

% tissue viability

Run / experiment:

1 hour

Value:

97

Results 2

Irritation / corrosion parameter:

% tissue viability

Run / experiment:

4.5 hours

Value:

103

Results 3

Irritation / corrosion parameter:

% tissue viability

Run / experiment:

20 hours

Value:

80

Any other information on results incl. tables

Test Article                                                                                  Percent                Percent

(% & Exposure)                             System                                 Viability               Inhibition

 

Dioctyldodecyl Dodecanedioate; Lot#: P-3955

(100% - 20 hrs.)                              EpiDerm                                       80                        20

(100% - 4.5 hrs.)                             EpiDerm                                     103                        -3

(100% - 1 hr.)                                  EpiDerm                                      97                           3

Triton X-100

(1% - 20 hrs.)                                 EpiDerm                                         4                          96

(1% - 4.5 hr.)                                 EpiDerm                                       91                            9

(1% - 1 hr.)                                    EpiDerm                                       93                            7

 

For the article, semi-log scales were used to plot the percent viabilities, on the linear y axis, versus the dosing times, on the log x axis. By interpolation and where possible, the time at which the percent viability would be 50% (ET-50) was estimated.

The test article, LIQUIWAX DIADD-LQ-(MH); Lot#: P-3955, elicited an ET-50 greater than 24 hours. The Triton X-100 reference article, at 1%, elicited an ET-50 of 9.1 hours. According to MatTek Corporation, as a general guideline, the following groupings can be used in assigning expected in vivo irritancy responses based on the ET-50 results obtained using MatTek's EpiDerm:

 

ET-50 (hrs)	Expected In vivo Irritancy	Example
<0.5	Severe, probably corrosive	Conc. Nitric Acid
0.5-4	Moderate	1% Sodium Dodecyl Sulfate
4-12	Moderate to Mild	1% Triton X-100
12-24	Very Mild	Baby Shampoo
24	Non-irritating	10% Tween 20

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Remarks:

ET-50 of test item > 24 hours therefore non-irritating

Conclusions:

Under the conditions of this test, the test article, Dioctyldodecyl Dodecanedioate; Lot P-3955, at 100%, has an expected in vivo dermal irritancy potential in the non-irritating range.

Executive summary:

The test article can be considered as non-irritant to the skin.