Reaction mass of 1-(3,3-dimethylcyclohexyl)ethyl acetate and 2,6,6-trimethylcycloheptanol acetate

Skin irritation / corrosion

Administrative data

Endpoint:

skin irritation: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2019-03-07 to 2019-04-17

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2019

Report date:

2019

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

2015

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method B.46 (In Vitro Skin Irritation: Reconstructed Human Epidermis Model Test)

Version / remarks:

2008

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

Reaction mass of 1-(3,3-dimethylcyclohexyl)ethyl acetate and 2,6,6-trimethylcycloheptanol acetate

EC Number:

949-569-5

Molecular formula:

C12H22O2

IUPAC Name:

Reaction mass of 1-(3,3-dimethylcyclohexyl)ethyl acetate and 2,6,6-trimethylcycloheptanol acetate

Test material form:

liquid

In vitro test system

Test system:

human skin model

Source species:

human

Cell type:

non-transformed keratinocytes

Cell source:

other: reconstruceted human skin model

Justification for test system used:

The applied test system is recommended by the guidelines followed.

Vehicle:

unchanged (no vehicle)

Details on test system:

RECONSTRUCTED HUMAN EPIDERMIS (RHE) TISSUE
- Model used: Epi-200-SIT Kit
- Tissue batch number: 28690

TEMPERATURE USED FOR TEST SYSTEM
- Temperature used during treatment / exposure: 37 °C
- Temperature of post-treatment incubation: 37 °C

REMOVAL OF TEST MATERIAL AND CONTROLS
-Volume and number of washing steps: rinsing with PBS for at least 15 times. After rinsing, the inserts were submerged in PBS at least three times. Afterwards the inserts were once again rinsed with sterile PBS from the inside and the outside. Excess PBS was removed by gently shaking the inserts and blotting the bottom with sterile blotting paper
- Observable damage in the tissue due to washing: none

MTT DYE USED TO MEASURE TISSUE VIABILITY AFTER TREATMENT / EXPOSURE
- MTT concentration: 1 mg/mL
- Incubation time: 3 h
- Spectrophotometer: Versamax® Molecular Devices, Softmax Pro Enterprise, version 4.7.1
- Wavelength: 570 nm

FUNCTIONAL MODEL CONDITIONS WITH REFERENCE TO HISTORICAL DATA
- Viability: yes
- Barrier function: yes
- Morphology: yes
- Contamination: none
- Reproducibility: yes

NUMBER OF REPLICATE TISSUES: 3

CONTROL TISSUES USED IN CASE OF MTT DIRECT INTERFERENCE
not applicable since the test item did not direclty interfere with MTT or changed color in the presence of water.

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

PREDICTION MODEL / DECISION CRITERIA (choose relevant statement)
- The test substance is considered to be irritating to skin if mean tissue viability after 1 h exposure is equal to or less than 50 % of the control
- The test substance is considered to be non-irritating to skin if mean tissue viability after 1 h exposure is greater than 50 % of the control

Control samples:

yes, concurrent negative control

yes, concurrent positive control

Amount/concentration applied:

TEST MATERIAL
- Amount applied: 30 µL

NEGATIVE CONTROL
- Amount applied: 30 µL

POSITIVE CONTROL
- Amount applied: 30 µL
- Concentration: 5 %

Duration of treatment / exposure:

60 min

Duration of post-treatment incubation (if applicable):

24 h

Number of replicates:

3

Results and discussion

In vitro

Results

Irritation / corrosion parameter:

% tissue viability

Run / experiment:

1

Value:

94.51

Vehicle controls validity:

not applicable

Negative controls validity:

valid

Positive controls validity:

valid

Other effects / acceptance of results:

OTHER EFFECTS:
- Visible damage on test system: none
- Direct-MTT reduction: no
- Colour interference with MTT: no

DEMONSTRATION OF TECHNICAL PROFICIENCY: yes

ACCEPTANCE OF RESULTS:
- Acceptance criteria met for negative control: yes
- Acceptance criteria met for positive control: yes
- Acceptance criteria met for variability between replicate measurements: yes

Any other information on results incl. tables

Table 1 Summary of results after 60 min treatment with the test item

Treatment group	Mean OD of 3 tissues	SD	Mean Rel Viability [%]
Negative control	1.840	4.9	100.0
Positive control	0.059	0.1	3.20
Test Item	1.739	1.5	94.51

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Conclusions:

In conclusion, it can be stated that in this study and under the experimental conditions reported, the test item is non-irritant to skin according to UN GHS and EU CLP regulation.

Executive summary:

This in vitro study was performed to assess the irritation potential of the test item by means of the Human Skin Model Test.

The test item did not reduce MTT (pre-test for direct MTT reduction), and it did not change colour when mixed with deionised water (pre-test for colour interference). Also, its intrinsic colour was not intensive. Consequently, additional tests with freeze-killed or viable tissues were not necessary. Each three tissues of the human skin model EpiDerm™ were treated with the test item, the negative control (DPBS) or the positive control (5 % SDS) for 60 minutes.

After treatment with the negative control the absorbance values were well within the required range of the acceptability criterion of mean OD ≥ 0.8 and ≤ 2.8 for the 60 minutes treatment interval, thus assuring the quality of the tissues.

Treatment with the positive control induced a sufficient decrease in the relative absorbance as compared to the negative control for the 60 minutes treatment interval, thus assuring the validity of the test system.

After treatment with the test item the mean relative viability value decreased to 94.51 % compared to the relative absorbance value of the negative control. This value is above the threshold for irritancy of ≤ 50 %. Therefore, the test item is not considered to possess an irritant potential.

In conclusion, it can be stated that in this study and under the experimental conditions reported, is non-irritant to skin.