3,3,5-trimethylcyclohexyl methacrylate

Skin irritation / corrosion

Administrative data

Endpoint:

skin corrosion: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

April / June 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

Qualifier:

according to guideline

Guideline:

OECD Guideline 431 (In Vitro Skin Corrosion: Human Skin Model Test)

Version / remarks:

2016

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

3,3,5-trimethylcyclohexyl methacrylate

EC Number:

231-927-0

EC Name:

3,3,5-trimethylcyclohexyl methacrylate

Cas Number:

7779-31-9

Molecular formula:

C13H22O2

IUPAC Name:

3,3,5-trimethylcyclohexyl 2-methylprop-2-enoate

Test material form:

liquid

In vitro test system

Test system:

human skin model

Source species:

human

Cell type:

non-transformed keratinocytes

Cell source:

other: epiCS, cell systems

Details on animal used as source of test system:

Human skin model: The 0.6 cm2 reconstitued epidermis (epiCS, cell systems, batch No.100-AG0648-1) were received on 19 April 2017. The insert (filter + epidermis) was gently removed from the agarose while avoiding leaving agarose on the polycarbonate filter. The same day, the insert was placed in a 6 wells culture plate which had been previously filled with 1ml of culture medium. The culture dishes were incubated at 37+/-2°C, 5% CO2, 19 hours and 55 minutes before treatment. Just before the treatment, the culture medium was replaced by a new culture medium.

Vehicle:

unchanged (no vehicle)

Details on test system:

Grading of reactions:
3 minutes and 1 hour after the test item application, the human epidermis was mashed 20 times with 1ml of DPBS. The rinsed tissue were checked for any coloration and noted to be whitish, comparable coloration to that of the negetive control tissues.
The cell viability was quantified by measurement of the cell succinate deshydrogenase activity. This enzyme was responsible for the MTT reduction into blue formazan crystal. The skin sample was placed in MTT solution of 1 mg/ml concentration for 3 hours between 37°C and 37.7°C, 5% CO2. The precipitated blue formazan product was then extracted using isopropanol during 2 hours under agitation in the dark, and the concentration of formazan was measured by determing the optical density (OD) at 570 nm, just after dilution of the extraction in isopropanol (1:3).
The absorbance was measured in triplicate of MTT extract. The ùeasured absorbances were proportional to the number of living cells.

Treatment of the results : The results were expressed as a viability percentage compared with the negative control.

Evaluation and interpretation of the results :
The OD values obtained for the test item were used to calculate a percentage of viability relative to the negative control, which was arbitrarily set at 100%. The cut-off values for the prediction of corrosion associated with the epiSC model were as follows :
-Viability < 50% after 3 min exposure: Corrosive (1A)
-Viability > or = 50% after 3 min exposure AND < 15% after 60 min exposure: Corrosive (1B/1C)
-Viability > or = 50% after 3 min exposure AND > or = 15% after 60 min exposure: Non-Corrosive

Acceptability criteria :
-Negative control: mean OD of the tissue replicates should be > or = 0.8 and < or = 2.8 for epiSC model for every exposure time
-Positive control: mean viability of the tissue replicates expsed for 1 hour, expressed as % of the negative control, should be < 20% for epiCS model
-Test item: in the range 20-100% viability, and for ODs < or = 0.3, difference of viability between the two tissue replicates should not exceed 30%

Control samples:

yes, concurrent negative control

yes, concurrent positive control

Amount/concentration applied:

The test item was applied, as supplied, at the dose of 50 µl at room temperature

Duration of treatment / exposure:

3 min, 1 hour

Number of replicates:

2

Results and discussion

In vitro

Results

Results 1

Irritation / corrosion parameter:

% tissue viability

Remarks:

3 min

Run / experiment:

treated

Value:

101.47

Vehicle controls validity:

not applicable

Negative controls validity:

valid

Remarks:

100%

Positive controls validity:

valid

Remarks:

4.11%

Results 2

Irritation / corrosion parameter:

% tissue viability

Remarks:

1 hour

Run / experiment:

treated

Value:

122.61

Vehicle controls validity:

not applicable

Negative controls validity:

valid

Remarks:

100%

Positive controls validity:

valid

Remarks:

0.83%

Other effects / acceptance of results:

ACCEPTANCE OF RESULTS:
- Acceptance criteria met for negative control: yes
- Acceptance criteria met for positive control: yes

Applicant's summary and conclusion

Interpretation of results:

other: not corrosive

Conclusions:

Based on these results, 3,3,5 -trimethylcyclohexylmethacrylate is not classified as skin corrosive.

Executive summary:

The aim of the study was to evaluate the possible corrosive effects of the test item after topical administratin on in vitro human reconstituted epidermis (epiCS, CellSystems).

The test item 3,3,5 -trimethylcyclohexylmethacrylate was applied as supplied, at the dose of 50 µl, to 2 Human skin modekl surfaces (epiCS, CellSystems) during 3 minutes and 1 hour, followed by a rinse with 20 ml of DPBS. Cell viability was then measured by enzymatic conversion of the vital dye MTT into a blue formazan salt that was quantitatively measured after extraction from tissues. The experimental protocol was established in accordance with the OECD TG 431.

Three minutes and 1 hour after the test item application, the mean percent viability of the epidermis skins treated with the test item were 101.47% and 122.61% when compared with the negative control (considered as 100%), versus 4.11% and 0.83%, respectively, with the positive control item (potassium hydroxide 8N).

All the acceptability criteria were met. This study is validated.

Based on these results, 3,3,5 -trimethylcyclohexylmethacrylate is not classified as skin corrosive.