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Diss Factsheets

Toxicological information

Skin irritation / corrosion

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Administrative data

Endpoint:
skin irritation: in vivo
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
comparable to guideline study with acceptable restrictions

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1989
Report date:
1989

Materials and methods

Test guideline
Qualifier:
no guideline followed
Principles of method if other than guideline:
- Principle of test: The study was conducted to determine the skin irritation index of tea tree oil in the rabbit by the Draize method.
- Short description of test conditions: The undiluted test item was applied to the intact and abraded skin of six New Zealand White rabbits.
- Parameters analysed / observed: Skin irritation reactions and clinical signs of toxicity or abnormal behaviour.
GLP compliance:
no

Test material

Constituent 1
Reference substance name:
Melaleuca alternifolia, ext.
EC Number:
285-377-1
EC Name:
Melaleuca alternifolia, ext.
Cas Number:
85085-48-9
Molecular formula:
Not applicable (a generic molecular formula cannot be provided for this specific UVCB substance).
IUPAC Name:
Essential oil of melaleuca alternifolia
Test material form:
liquid
Specific details on test material used for the study:
- Batch no.: 88/375
- Purity: 100%

Test animals

Species:
rabbit
Strain:
New Zealand White
Details on test animals or test system and environmental conditions:
- Source: Not specified.
- Age at study initiation: Young mature albino rabbits were used.
- Weight at study initiation: Not specified.
- Housing: Not described.
- Diet: Not specified.
- Water: Not specified.
- Acclimation period: Not specified.
- Temperature: 22°C.
- Humidity: Not specified.
- Air changes: Not specified.
- Photoperiod: Not specified.

Test system

Type of coverage:
not specified
Preparation of test site:
other:
Remarks:
Abraded and intact skin were examined for each animal.
Vehicle:
unchanged (no vehicle)
Controls:
not required
Amount / concentration applied:
Dose: 0.5ml.
Concentration: 100% (undiluted).
Duration of treatment / exposure:
72 hours.
Observation period:
All animals were observed for signs of toxicity and abnormal behaviour during the experimental period. The observation period is not specified.
Number of animals:
6 animals.
Details on study design:
Procedure: P.C.S method number 1 was used.
Area of exposure: Not specified.
Removal of test substance: Not described.
Observation time points: 24 hours and 72 hours.
The Draize scale for scoring skin reactions is shown in the attached scoring system.

Results and discussion

In vivo

Resultsopen allclose all
Irritation parameter:
erythema score
Remarks:
intact skin
Basis:
animal #1
Remarks:
mean
Time point:
other: 24/72 h
Score:
2.5
Max. score:
3
Reversibility:
not specified
Remarks on result:
other: Timepoints
Remarks:
Only 24 h and 72 h timepoints were reported
Irritation parameter:
erythema score
Remarks:
intact skin
Basis:
animal #2
Remarks:
mean
Time point:
other: 24/72 h
Score:
3
Max. score:
3
Reversibility:
not specified
Remarks on result:
other: Timepoints
Remarks:
Only 24 h and 72 h timepoints were reported
Irritation parameter:
erythema score
Remarks:
intact skin
Basis:
animal #3
Remarks:
mean
Time point:
other: 24/72 h
Score:
3.5
Max. score:
4
Reversibility:
not specified
Remarks on result:
other: Timepoints
Remarks:
Only 24 h and 72 h timepoints were reported
Irritation parameter:
erythema score
Remarks:
intact skin
Basis:
animal #4
Remarks:
mean
Time point:
other: 24/72 h
Score:
3.5
Max. score:
4
Reversibility:
not specified
Remarks on result:
other: Timepoints
Remarks:
Only 24 h and 72 h timepoints were reported
Irritation parameter:
erythema score
Remarks:
intact skin
Basis:
animal #5
Remarks:
mean
Time point:
other: 24/72 h
Score:
3
Max. score:
3
Reversibility:
not specified
Remarks on result:
other: Timepoints
Remarks:
Only 24 h and 72 h timepoints were reported
Irritation parameter:
erythema score
Remarks:
intact skin
Basis:
animal #6
Remarks:
mean
Time point:
other: 24/72 h
Score:
3
Max. score:
3
Reversibility:
not specified
Remarks on result:
other: Timepoints
Remarks:
Only 24 h and 72 h timepoints were reported
Irritation parameter:
edema score
Remarks:
intact skin
Basis:
animal #1
Remarks:
mean
Time point:
other: 24/72 h
Score:
1.5
Max. score:
2
Reversibility:
not specified
Remarks on result:
other: Timepoints
Remarks:
Only 24 h and 72 h timepoints were reported
Irritation parameter:
edema score
Remarks:
intact skin
Basis:
animal #2
Remarks:
mean
Time point:
other: 24/72 h
Score:
2
Max. score:
2
Reversibility:
not specified
Remarks on result:
other: Timepoints
Remarks:
Only 24 h and 72 h timepoints were reported
Irritation parameter:
edema score
Remarks:
intact skin
Basis:
animal #3
Remarks:
mean
Time point:
other: 24/72 h
Score:
2
Max. score:
2
Reversibility:
not specified
Remarks on result:
other: Timepoints
Remarks:
Only 24 h and 72 h timepoints were reported
Irritation parameter:
edema score
Remarks:
intact skin
Basis:
animal #4
Remarks:
mean
Time point:
other: 24/72 h
Score:
2
Max. score:
2
Reversibility:
not specified
Remarks on result:
other: Timepoints
Remarks:
Only 24 h and 72 h timepoints were reported
Irritation parameter:
edema score
Remarks:
intact skin
Basis:
animal #5
Remarks:
mean
Time point:
other: 24/72 h
Score:
2
Max. score:
2
Reversibility:
not specified
Remarks on result:
other: Timepoints
Remarks:
Only 24 h and 72 h timepoints were reported
Irritation parameter:
edema score
Remarks:
intact skin
Basis:
animal #6
Remarks:
mean
Time point:
other: 24/72 h
Score:
1.5
Max. score:
2
Reversibility:
not specified
Remarks on result:
other: Timepoints
Remarks:
Only 24 h and 72 h timepoints were reported
Irritant / corrosive response data:
Irritation reactions were observed on both intact and abraded skin after treatment with the test sample. The primary irritation index was found to be 5.0.

Any other information on results incl. tables

Table 1. Details on skin irritation reactions.

 Animal No.  Intact Skin  Abraded Skin  Score  Time of Evaluation
 Erythema  Oedema  Erythema  Oedema
 1  2  1  2  1  6  24 hours
 3  2  3  2  10  72 hours
 2  3  2  3  2  10  24 hours
 3  2  3  2  10  72 hours
 3  3  2  3  2  10  24 hours
 4  2  4*  2  12  72 hours
 4  3  2  3  3  11  24 hours
 4  2  4*  2  12  72 hours
 5  3  2  3  2  10  24 hours
 3  2  4*  2  11  72 hours
 6  3  2  3  2  10  24 hours
 3  1  4  2  10  72 hours
 Total  28  29  57  24 hours
 31  34  65  72 hours
 Index  4.7  4.8  4.8  24 hours
 5.2  5.7  5.4  72 hours

Primary Irritation Index: 5.0

* erosion

Applicant's summary and conclusion

Interpretation of results:
Category 2 (irritant) based on GHS criteria
Conclusions:
Given mean values for erythema at 24 and 72 hours of more than 2.3 in all treated animals, Tea Tree Oil is considered to be a Category 2 Irritant.
Executive summary:

Acute dermal irritation testing was carried out on six young mature albino rabbits (NZ). The test sample was administered undiluted, as supplied. All animals were observed for signs of toxicity and abnormal behaviour during the experimental period. Irritation reactions were observed on both intact and abraded skin after treatment with the test sample. The Draize irritation index was found to be 5.0, indicating a severe irritant. Based on GHS criteria, and given mean values for erythema at 24 and 72 hours of more than 2.3 in all treated animals, Tea Tree Oil is considered to be a Category 2 Irritant.