1,5,10-trimethylcyclododeca-1,5,9-triene, epoxidised

Skin irritation / corrosion

Administrative data

Endpoint:

skin irritation: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

From 30 September to 05 October 2015

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2016

Report date:

2016

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)

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

Principles of method if other than guideline:

Not applicable

GLP compliance:

yes (incl. QA statement)

Remarks:

UK GLP Compliance Program (inspected on June 17, 2015 / Signed on September 24, 2015)

Test material

Test material information

Constituent 1

Reference substance name:

1,5,10-trimethylcyclododeca-1,5,9-triene, epoxidised

EC Number:

945-746-6

Molecular formula:

Not Applicable

IUPAC Name:

1,5,10-trimethylcyclododeca-1,5,9-triene, epoxidised

Test material form:

liquid

Details on test material:

- Physical state: Yellowish liquid
- Storage condition of test material: Stored at ambient temperature in the dark
- Stability under storage conditions: Stable
- Solubility in water: Poor

In vitro test system

Test system:

human skin model

Source species:

human

Cell type:

non-transformed keratinocytes

Justification for test system used:

Following the REACH bottom-up strategy, the EPISKIN™ Reconstructed Human Epidermis Model method was used to assess skin irritation as recommended in the OECD test guideline No. 439.

Vehicle:

unchanged (no vehicle)

Details on test system:

RECONSTRUCTED HUMAN EPIDERMIS (RHE) TISSUE
- Model used: EPISKIN™ Reconstructed Human Epidermis Model Kit, SkinEthic Laboratories, Lyon, France
- Tissue batch number(s): 15-EKIN-039
- Production date: not reported
- Shipping date: 29 September 2015
- Delivery date: 29 September 2015
- Expiry date: 05 October 2015
- Date of initiation of testing: 30 September 2015

TEMPERATURE USED FOR TEST SYSTEM
- Temperature used during treatment / exposure: room temperature
- Temperature of post-treatment incubation (if applicable): 37°C

REMOVAL OF TEST MATERIAL AND CONTROLS
- Volume and number of washing steps: not reported. At the end of the treatment period, each tissue was rinsed with Dulbeccos Phosphate Buffered Saline (DPBS) with Ca++ and Mg++ to remove any residual test or control items and then incubated in 2mL maintenance medium for 42 h at 37 °C, 5 % CO2 in air.
- Observable damage in the tissue due to washing: none reported
- Modifications to validated SOP: none reported

MTT DYE USED TO MEASURE TISSUE VIABILITY AFTER TREATMENT / EXPOSURE
- MTT concentration: 0.3 mg/mL
- Incubation time: 3 hours
- Spectrophotometer: Anthos 2001 microplate reader
- Wavelength: 562 nm (without a reference filter)
- Filter: not applicable
- Filter bandwidth: not applicable
- Linear OD range of spectrophotometer: no data reported

FUNCTIONAL MODEL CONDITIONS WITH REFERENCE TO HISTORICAL DATA
- Viability: negative control OD values: 0.704, 0.508 and 0.621 (mean historical OD of the negative control was 0.830; range 0.629 – 1.245.)
The mean OD for the negative control treated tissues narrowly exceeded the lower end of the historical range at 0.611. This was attributed to one of the triplicate negative control tissues producing a low OD of 0.508. However the outlining tissue still produced a clear relative viability of 83.1%.
- Barrier function: IC50 = 2.3 mg/ml ( ≥ 1.5 mg/ml)
- Morphology: Well-differenciated epidermis consisting of a basal layer, several spinous and granular layers and a thinck stratum corneum
- Contamination: absence of bacteria, fungus and mycoplasma
- Reproducibility: For the previous 27 experiments conducted between 14 April 2015 and 21 September 2015 using this test method, the mean OD of the positive control was 0.094; range 0.049 to 0.198 and the mean percentage viability was 11.1; range 4.0 to 23.8 (The assay establishes the acceptance criterion for an acceptable test if the relative mean tissue viability for the positive control treated tissues was ≤40% relative to the negative control treated tissues, and the standard deviation value of the percentage viability is ≤18%). In this same period the mean OD of the negative control was 0.830; range 0.629 – 1.245 (The assay establishes the acceptance criterion for an acceptable test if the mean OD 562 for the negative control treated tissues was ≥0.6 and ≤1.5).

CONTROL TISSUES USED IN CASE OF MTT DIRECT INTERFERENCE: not applicable

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

PREDICTION MODEL / DECISION CRITERIA
- The test substance is considered to be irritating to skin if relative mean tissue viability is ≤ 50% after 15 minutes of exposure.
- The test substance is considered to be non-irritating to skin if relative mean tissue viability is > 50% after 15 minutes of exposure.

Control samples:

yes, concurrent negative control

yes, concurrent positive control

Amount/concentration applied:

TEST MATERIAL
- The test item was used as supplied (undiluted).
- Amount(s) applied (volume or weight with unit): 10 μL (26.3 μL /cm2) of the test item was applied to the epidermis surface.

NEGATIVE CONTROL
- Amount(s) applied (volume or weight): 10 μL

POSITIVE CONTROL
- Amount(s) applied (volume or weight): 10 μL
- Concentration (if solution): Sodium Dodecyl Sulphate (SDS) at a 5% (w/v) aqueous solution

Duration of treatment / exposure:

The EpiSkin™ human epidermis skin constructs were treated with the undiluted test item for an exposure period of 15 minutes.

Duration of post-treatment incubation (if applicable):

At the end of the exposure period, tissues were rinsed and incubated at 37 °C, 5% CO2 in air for 42 h.

Number of replicates:

Triplicate tissues for test item, negative and positive controls

Results and discussion

In vitro

Results

Irritation / corrosion parameter:

% tissue viability

Run / experiment:

15 minute exposure period and 42 h post-exposure incubation period

Value:

36.6

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: no
- 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

Direct MTT Reduction: The MTT solution containing the test item did not turn blue which indicated that the test item did not directly reduce MTT.

 

Assessment of Color Interference with the MTT endpoint: The solution containing the test item was colorless. It was therefore unnecessary to run color correction tissues.

 

Table 7.3.1/1: Mean OD₅₆₂Values and Percentage Viabilities for the Negative Control Item, Positive Control Item and Test Item 

Item	OD562 of tissues	Mean OD562 of triplicate tissues	±SD of OD562	Relative individual tissue viability (%)	Relative mean viability (%)	± SD of Relative mean viability (%)
Negative Control Item	0.704	0.611	0.098	115.2	100*	16.1
	0.508			83.1
	0.621			101.6
Positive Control Item	0.136	0.114	0.032	22.3	18.7	5.3
	0.129			21.1
	0.077			12.6
Test Item	0.306	0.224	0.071	50.1	36.6	11.7
	0.185			30.3
	0.180			29.5

 

SD=Standard deviation; *= The mean viability of the negative control tissues is set at 100%; OD₅₆₂= Optical Density

 

Quality Criteria

The relative mean tissue viability for the positive control treated tissues was 18.7% relative to the negative control treated tissues and the standard deviation value of the viability was 5.3. The positive control acceptance criteria were therefore satisfied.

The mean OD₅₆₂ for the negative control treated tissues was 0.611 and the standard deviation value of the viability was 16.1. The negative control acceptance criteria were therefore satisfied.

The standard deviation calculated from individual tissue viabilities of the three identically test item treated tissues was 11.7. The test item acceptance criterion was therefore satisfied.

Applicant's summary and conclusion

Interpretation of results:

Category 2 (irritant) based on GHS criteria

Conclusions:

Under the test conditions, test material is classified as H315 “Causes Skin Irritation” Category 2 according to Regulation (EC) No. 1272/2008 (CLP) and to the GHS

Executive summary:

An in vitro skin irritation study was performed according to the OECD Guideline 439 and in compliance with GLP, using the EPISKIN^TM reconstructed human epidermis model. Triplicate tissues were treated with 10 μL of the undiluted test item for an exposure period of 15 minutes. At the end of the exposure period each tissue was rinsed before incubating for 42 h. At the end of the post-exposure incubation period each tissue was taken for MTT-loading. At the end of the formazan extraction period, the optical density was measured at 562 nm. Data are presented in the form of percentage viability (MTT reduction in the test item treated tissues relative to negative control tissues).

This assay was valid with negative and positive controls showing results within the acceptable range.

The test substance with a mean tissue viability of 36.6 ± 11.7 %, was predicted as irritant to the skin. The quality criteria required for acceptance of results in the test were satisfied.

 

Under the test conditions, test material is classified as H315 “Causes Skin Irritation” Category 2 according to Regulation (EC) No. 1272/2008 (CLP) and to the GHS.

This study is considered as acceptable and satisfies the requirement for skin irritation endpoint.