p-mentha-1,3-diene

Skin irritation / corrosion

Administrative data

Endpoint:

skin irritation: in vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2007

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

data from handbook or collection of data

Data source

Reference

Reference Type:

publication

Title:

Examination of a -terpinene on Primary Eye Irritancy and Skin Sensitization

Author:

Park B.S.

Year:

2007

Bibliographic source:

Mol. Cell. Toxicol. Vol. 3(1), 68-75, 2007

Report date:

2007

Materials and methods

Test guideline

Test guideline 1

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 404 (Acute Dermal Irritation / Corrosion)

Test guideline 2

Qualifier:

according to guideline

Guideline:

other: Korean Food and Drug Administration (KFDA) guidelines

GLP compliance:

not specified

Test material

Test material information

Constituent 1

Reference substance name:

p-mentha-1,3-diene

EC Number:

202-795-1

EC Name:

p-mentha-1,3-diene

Cas Number:

99-86-5

Molecular formula:

C10H16

IUPAC Name:

1-isopropyl-4-methylcyclohexa-1,3-diene

Test material form:

liquid

Details on test material:

Clear colourless liquid.

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL

- Source and lot/batch No.of test material: alpha terpinene was purchased from Sigma (St. Louis, MO)

FORM AS APPLIED IN THE TEST: Formulation of test repellents.
Repellent solution prepared using 0.5 g (2.0%) of alpha terpinene.

Test animals

Species:

rabbit

Strain:

New Zealand White

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: New Zealand white, Sejin Laboratory Co. (Seoul, South Korea)
- Age at study initiation: 12-18 weeks of age
- Weight at study initiation: male (2.8-3.3 kg) and female (2.7-3.4 kg)
- Acclimation period: yes, for 5 days before testing

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 16-21.6 °C
- Humidity (%): of 40-70%
- Air changes (per hr): not specified
- Photoperiod (hrs dark / hrs light): 12 h photoperiod

Test system

Type of coverage:

occlusive

Preparation of test site:

shaved

Remarks:

dorsal trunk

Vehicle:

other: Formulation of test repellents

Controls:

not specified

Amount / concentration applied:

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): A volume of 0.5 mL repellent solution
- Concentration: 0.5 g (2.0%) of alpha terpinene in repellent solution

NEGATIVE CONTRL - yes

POSITIVE CONTROL - no

Duration of treatment / exposure:

4 hrours

Observation period:

24 h and 72 h

Number of animals:

Three males and three females were tested

Details on study design:

TEST SITE
- Area of exposure: dorsal trunk
- % coverage: 100% After applying the test compound polyethylene wrap was secured around the trunk of the rabbit. Rabbits were placed in a restraining cage for 4 h treatment. After that time which wraps were removed.
- Type of wrap if used: 1-inch square gauze patch was placed on the skin and secured with adhesive tape.

OBSERVATION TIME POINTS - 24 h and 72 h

SCORING SYSTEM: provided

Four different skin sensitivity cohorts were examined, as follows:
(1) non-treated at intact site (NTN group)
(2) non-treated at abraded site (NTA group),
(3) 2% a -terpinene solution at intact site (2TN group),
(4) 2% a -terpinene solution at abraded site (2TA group).

Each test rabbit had 3 intact sites and 3 abraded sites.

Results and discussion

In vivo

Results

Results 1

Irritation parameter:

erythema score

Remarks:

scoring based on the final results

Basis:

mean

Time point:

24/48/72 h

Score:

> 0 - <= 2

Max. score:

4

Reversibility:

fully reversible

Remarks on result:

other: no scoring provided

Remarks:

No acute abnormalities were observed to intact or abraded skin after application of 2% alpha terpinene in rabbits.

Results 2

Irritation parameter:

edema score

Remarks:

scoring based on the final results

Basis:

mean

Time point:

24/48/72 h

Score:

> 0 - <= 2

Max. score:

4

Reversibility:

fully reversible

Remarks on result:

other: no scoring provided

Remarks:

No acute abnormalities were observed to intact or abraded skin after application of 2% alpha terpinene in rabbits.

Applicant's summary and conclusion

Interpretation of results:

other: not skin irritant

Conclusions:

No acute abnormalities were observed to intact or abraded skin after application of 2% alpha terpinene in rabbits.

Executive summary:

In this study, the skin irritation potential was investigated in New Zealand white rabbits using the repellent solution containing 0.5 g (2.0%) of alpha terpinene.

The local skin reactions were read and recorded at 24 h and 72 h using the scoring system. A skin biopsy was taken at 72 h after treatment for histological studies. The skin biopsies were fixed in 10% buffered formalin solution for several days, then underwent ethanol series dehydration and embedded in paraffin. Sections were stained with hematoxylin-eosin and examined under a light microscope.

Results demonstrated, that no acute abnormalities were observed to intact or abraded skin after application of 2% alpha terpinene in rabbits.