Juniper, Juniperus mexicana, ext.

Skin irritation / corrosion

Administrative data

Endpoint:

skin corrosion: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

20-07-2017 to 21-07-2017

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2017

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

adopted 29 July 2016

Deviations:

no

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Essential oil of Cedarwood Texas obtained from the wood of Juniperus mexicana (Cupressaceae) by distillation - Cedrol

IUPAC Name:

Essential oil of Cedarwood Texas obtained from the wood of Juniperus mexicana (Cupressaceae) by distillation - Cedrol

Test material form:

solid

Remarks:

LIGHT YELLOW, SOLID MASS

Details on test material:

Name of test material as cited in study report: Cedrol - Cedarwood Texas oil distilled
Mfg Date 01/26/2016
Exp Date 01/25/2019

- Identification: Cedrol, Cedarwood Texas oil distilled
- Appearance: Light yellow, solid mass
- Batch: B-64530
- Purity/Composition: UVCB
- Test item storage: At room temperature
- Stable under storage conditions until: 25 January 2019 (expiry date)

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: at room temperature protected from light

ODOUR DESCRIPTION: CONFORMS TO STANDARD

Specific details on test material used for the study:

- Identification: Cedrol, Cedarwood Texas oil distilled
- Appearance: Light yellow, solid mass
- Batch: B-64530
- Purity/Composition: UVCB
- Test item storage: At room temperature
- Stable under storage conditions until: 25 January 2019 (expiry date)

TREATMENT OF TEST MATERIAL PRIOR TO TESTING
- Treatment of test material prior to testing: Test item should be equilibrated to 100°C for several minutes until completely liquefied to obtain a homogeneous sample.

In vitro test system

Test system:

human skin model

Source species:

human

Cell type:

non-transformed keratinocytes

Cell source:

other: MatTek Corporation

Source strain:

other: Keratinocyte strain 00267

Justification for test system used:

Recommended test system in international guidelines (OECD and EC).

Vehicle:

unchanged (no vehicle)

Details on test system:

RECONSTRUCTED HUMAN EPIDERMIS (RHE) TISSUE
- Model used: EpiDerm Skin Model
- Tissue batch number(s): Lot no.: 26708 Kit L and Kit M
- Production date: 19-07-2017
- Date of initiation of testing: 20-07-2017

TEMPERATURE USED FOR TEST SYSTEM
- Temperature used during treatment / exposure: 3 min room temperature, 1 hour 37ºC

REMOVAL OF TEST MATERIAL AND CONTROLS
- Washing step: washed with phosphate buffered saline
- Damage: no visual damage

MTT DYE USED TO MEASURE TISSUE VIABILITY AFTER TREATMENT / EXPOSURE
- MTT concentration: MTT concentrate (5 mg/ml) diluted (1:5) with MTT diluent (supplemented DMEM)
- Incubation time: 3 hours
- Spectrophotometer: TECAN Infinite® M200 Pro Plate Reader
- Wavelength: 570 nm

FUNCTIONAL MODEL CONDITIONS WITH REFERENCE TO HISTORICAL DATA
- Viability: The absolute mean OD570 of the two tissues of the negative control should reasonably be within the laboratory historical control data range. The mean relative tissue viability following 1-hour exposure to the positive control should be <15 %.
- Reproducibility: In the range 20 - 100% viability, the Coefficient of Variation (CV) between tissue replicates should be  30%.

NUMBER OF REPLICATE TISSUES: 2

NUMBER OF INDEPENDENT TEST SEQUENCES / EXPERIMENTS TO DERIVE FINAL PREDICTION:
- 1 experiment with 3 minute application (in duplicate)
- 1 experiment with 1 hour application (in duplicate)

PREDICTION MODEL / DECISION CRITERIA (choose relevant statement)
- The test substance is considered to be corrosive to skin if
a) The relative mean tissue viability obtained after 3-minute treatment compared to the negative control tissues is decreased below 50%.
b) In addition, a test item considered non-corrosive (viability >= 50%) after the 3-minute treatment is considered corrosive if the relative tissue viability after 1-hour treatment with the test item is decreased below 15%.
- The test substance is considered to be non-corrosive to skin if
a) The relative mean tissue viability obtained after the 3-minute treatment compared to the negative control tissues is not decreased below 50%.
b) In addition, the relative tissue viability after the 1-hour treatment is not decreased below 15%.

Control samples:

yes, concurrent negative control

yes, concurrent positive control

Amount/concentration applied:

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 50µL

NEGATIVE CONTROL
- Amount(s) applied (volume or weight): 50µL

POSITIVE CONTROL
- Amount(s) applied (volume or weight): 50µL
- Concentration (if solution):8N

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

Run / experiment:

3 min exposure

Value:

104

Vehicle controls validity:

not applicable

Negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

no indication of irritation

Results 2

Irritation / corrosion parameter:

% tissue viability

Run / experiment:

1 hour exposure

Value:

116

Vehicle controls validity:

not applicable

Negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

no indication of irritation

Other effects / acceptance of results:

- OTHER EFFECTS: no

DEMONSTRATION OF TECHNICAL PROFICIENCY:

ACCEPTANCE OF RESULTS:
- Acceptance criteria met for negative/positive control:
The absolute mean OD570 (optical density at 570 nm) of the negative control tissues was within the acceptance limits of OECD 431 (lower acceptance limit ≥0.8 and upper acceptance limit <=2.8) and the laboratory historical control data range.
- Acceptance criteria met for variability between replicate measurements: The mean relative tissue viability following the 1-hour exposure to the positive control was 10%.
In the range of 20 - 100% viability the Coefficient of Variation between tissue replicates was <=8.0%, indicating that the test system functioned properly.
- Range of historical values (OD570):

Negative control Positive control Positive control
3-minute treatment 1-hour treatment 3-minute treatment 1-hour treatment 3-minute treatment 1-hour treatment
Range 1.324 – 2.615 1.361 – 2.352 0.0172 – 0.56 0.046 – 0.339 6 – 25 3 – 13
Mean 1.84 1.85 0.19 0.14 11.03 7.45
SD 0.26 0.22 0.09 0.06 4.39 2.51
n 81 83 80 77 38 38

Applicant's summary and conclusion

Interpretation of results:

other: not classified

Remarks:

based on CLP criteria

Conclusions:

Under the conditions of the test, the Cedrol, Cedarwood Texas oil distilled was not corrosive. Based on this result, the substance does not need to be classified for skin corrosion in accordance with the criteria outlined in Annex I of the CLP Regulation (1272/2008/EC).

Executive summary:

Cedrol, Cedarwood Texas oil distilled was evaluated for its ability to induce skin corrosion on a human three dimensional epidermal model according to OECD TG 431.  Cedrol, Cedarwood Texas oil distilled was applied topically for 3 minutes and 1 hour. The test substance was equilibrated to 100°C for several minutes until completely liquefied to obtain a homogeneous liquid sample.  Cedrol, Cedarwood Texas oil distilled (50 µl) was applied directly on top of the skin tissue.  

The positive control had a mean relative tissue viability of 10% after the 1-hour exposure.  The absolute mean OD570 (optical density at 570 nm) of the negative control tissues was within the acceptance limits of OECD 431 (lower acceptance limit ≥ 0.8 and upper acceptance limit ≤ 2.8) and the laboratory historical control data range.  In the range of 20 - 100% viability the Coefficient of Variation between tissue replicates was ≤ 8.0%, indicating that the test system functioned properly.

The relative mean tissue viability obtained after 3-minute and 1-hour treatments with Cedrol, Cedarwood Texas oil distilled compared to the negative control tissues was 104% and 116%, respectively.  Because the mean relative tissue viability for Cedrol, Cedarwood Texas oil distilled was above 50% after the 3-minute treatment and above 15% after the 1-hour treatment Cedrol, Cedarwood Texas oil distilled is considered to be not corrosive.

In conclusion, Cedrol, Cedarwood Texas oil distilled is not corrosive in the in vitro skin corrosion test under the experimental conditions described.