Eugenol

Skin irritation / corrosion

Administrative data

Endpoint:

skin irritation: in vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1988

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

Study design appears to follow OECD guideline 404 (2002) with deviations (purity not reported, number of animals, lower room temperature, reversibility effects not examined, and rationale for in vivo testing not provided). A GLP statement and quality assurance statement were provided. It should be noted that 4 unique test materials were tested in the same animal.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1988

Report date:

1988

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 404 (Acute Dermal Irritation / Corrosion)

Deviations:

yes

Remarks:

purity not reported, number of animals, lower room temperature, reversibility effects not examined, and rationale for in vivo testing not provided

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Eugenol

EC Number:

202-589-1

EC Name:

Eugenol

Cas Number:

97-53-0

Molecular formula:

C10H12O2

IUPAC Name:

2-methoxy-4-(prop-2-en-1-yl)phenol

Details on test material:

Name of the test material as cited in the report: Eugenol
- Physical state: Liquid
- Storage condition of test material: When test materials were not in use, they were stored in the dark at approximately +4°C.
Further details not reported.

Test animals

Species:

rabbit

Strain:

New Zealand White

Details on test animals or test system and environmental conditions:

Healthy female New Zealand White rabbits were obtained from Gorseside Rabbits, Northchurch, Berkhamsted, Herfordshire, and were delivered by road transport. Animals were ordered aged 10-12 weeks and weighing approximately 2 kg. On arrival, the animals were identified in the ear with an individual number stamped onto a metal tag. Animals were allowed an acclimatisation period of at least five days.

The rabbits were individually housed in grid bottomed metal cages. A commercially available antibiotic free rabbit diet (SQC standard rabbit pellets produced by Special Diets Services, Witham, Essex) and mains drinking water via automatic nozzles in each cage were available at libitum.

The rabbit holding room was air-conditioned with temperature in the range of 5-24°C and relative humidity in the range of 37-68% during the acclimatisation and study periods. The system was set to maintain temperature within the range of 17-23°C but the heating equipment failed during the acclimatisation period, resulting in the low temperatures recorded. Temperature was typically greater than 14°C during the study period. Fluorescent lighting was controlled to give an artificial cycle of 12 hours light/l2 hours dark per day.

Test system

Type of coverage:

semiocclusive

Preparation of test site:

other: clipped

Vehicle:

unchanged (no vehicle)

Controls:

not required

Amount / concentration applied:

0.5 mL of the test material

Duration of treatment / exposure:

4 hours

Observation period:

7 days

Number of animals:

4

Details on study design:

To evaluate and compare the degree of irritation to intact skin of the albino rabbit following four hours semi-occluded contact with a number of fragrance materials among which Eugenol.

The day before dosing commenced, rabbits were placed in restraining stocks and the dorsal surfaces of the trunk clipped free of hair. Six groups, each of 4 animals with healthy intact skin were selected for the study.

On the day of dosing, selected animals were placed in restraining stocks. 0.5 ml of one test material was placed evenly over a 2.5cm square of surgical lint. The lint square was then placed onto the animal’s skin, on the left flank and immediately caudal to the last rib, with the test material in contact with the skin. A second material was applied in the same manner to the skin of the right flank, bilateral to the first material. One or two other materials were applied caudal to the sites dosed with the first two materials. The lint patches were held in place by encircling the trunk of the animal with a length of ‘Elastoplast’ elastic adhesive bandage 10cm wide.

This also served as a semi-occlusive barrier to the treated skin. All rabbits were treated in this manner, the 4 test materials being placed in different positions on the back of each animal of the group. Animals remained in the restraining stocks during the dosing period. After a period of 4 hours, the adhesive tapes were removed and the treated sites cleansed by gentle swabbing with cotton wool soaked in warm water. The animals were then returned to their cages.

Results and discussion

In vivo

Results

Results 1

Irritation parameter:

erythema score

Basis:

mean

Time point:

24/48/72 h

Score:

1.9

Max. score:

4

Reversibility:

not fully reversible within: 7 days

Results 2

Irritation parameter:

edema score

Basis:

mean

Time point:

24/48/72 h

Score:

1

Max. score:

4

Reversibility:

not fully reversible within: 7 days

Irritant / corrosive response data:

The average scores calculated from the numerical values given to the irritation observed at the twenty four, forty eight and seventy two hour observations were 1.9 for erythema and 1.0 for oedema.

Other effects:

At the 7-day observation time-point, slight desquamation was reported in one individual rabbit on Day 7 (no further details reported).

Any other information on results incl. tables

One hour after removal of the patches and excess test material, the treated sites were assessed for signs of reaction to treatment. Similar examinations were undertaken twenty four, forty eight, and seventy two hours, and seven days after patch removal. Animals were examined under a standard light source designed to comply with the requirements of B.S. 950 Part 1 (Artificial Daylight for the Assessment of Colour). Irritation was assessed and allocated a numerical value based on the table below.

Erythema and Eschar Formation:

No erythema: 0

Very slight erythema (barely perceptible): 1

Well defined erythema: 2

Moderate to severe erythema: 3

Severe erythema (beet redness) to slight eschar formation (injuries in depth): 4

Oedema Formation Value:

No oedema: 0

Very slight oedema (barely perceptible):1

Slight oedema (edges of area well defined by definite raising): 2

Moderate oedema (raised approximately 1mm): 3

Severe oedema (raised more than 1mm and extending beyond area of exposure): 4

Details on the results:

1 hour observation
rabbit number	erythema	oedema
292	0.5	0.5
254	0.5	0.5
306	1.5	1
313	2	1
24 hours observation
rabbit number	erythema	oedema
292	2	1.5
254	2	1.5
306	2	0.5
313	2	1
48 hours observation
rabbit number	erythema	oedema
292	2	1.5
254	1.5	1
306	2	1
313	2	1
72 hours observation
rabbit number	erythema	oedema
292	2	1
254	1.5	0.5
306	2	0.5
313	2	1
7 days observation
rabbit number	erythema	oedema
292	0	0
254	0	0
306	1	0.5
313	2	0.5

Applicant's summary and conclusion

Interpretation of results:

not classified

Remarks:

Migrated information Criteria used for interpretation of results: EU

Conclusions:

The mean value obtained for both erythema and edema was less than two; thus, the authors concluded that the test material is considered not to be an irritant. Based on the results, eugenol has a mean value of <2.3 for erythema or for oedema for all 4 animals from gradings at 24, 48, and 72 hours. While the recovery period did not extend to 14 days, there were signs of recovery after 7 days in 3 out of 4 animals; only 1 out of 4 animals had signs of continued irritation and slight scaling after 7 days. There was no sign of pronounced variability in the response among the animals.

Executive summary:

The potential for skin irritation from dermal exposure to eugenol (4 hours, semi-occluded conditions, undiluted test material) was assessed in female rabbits. The average scores calculated from the numerical values given for the irritation observed at the 24-, 48- and 72-hour observations were 1.9 for erythema and 1.0 for oedema. As the mean value obtained for both erythema and edema was less than two, it was concluded that the test material is considered not to be an irritant.

Based on the results, eugenol has a mean value of <2.3 for erythema or for oedema for all 4 animals from gradings at 24, 48, and 72 hours. While the recovery period did not extend to 14 days, there were signs of recovery after 7 days in 3 out of 4 animals; only 1 out of 4 animals had signs of continued irritation and slight scaling after 7 days. There was no sign of pronounced variability in the response among the animals.

.