2-methyl-3-(p-tolyl)propionaldehyde

Skin irritation / corrosion

Administrative data

Endpoint:

skin irritation: in vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

From September 09, 1987 to September 16, 1987

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1987

Report date:

1987

Materials and methods

Test guideline

Qualifier:

no guideline followed

Principles of method if other than guideline:

No guideline available in the report as the test has been performed prior to the OECD guideline.
The objective of the assay was to evaluate and compare the degree of irritation to the intact skin of the albino rabbit following four hours semi-occluded contact with the test substance. The procedures used were based on the test for skin irritation described on pages 106 to 108 of document L251, an EEC Commission Directive of 25th April 1984. This describes the laws, regulations and administrative provisions relating to the classification, packaging and labelling of dangerous substances. The methods of classification used are described by a Directive of 16th September 1983 (L257).

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

2-methyl-3-(p-tolyl)propionaldehyde

EC Number:

255-410-4

EC Name:

2-methyl-3-(p-tolyl)propionaldehyde

Cas Number:

41496-43-9

Molecular formula:

C11H14O

IUPAC Name:

2-methyl-3-(4-methylphenyl)propanal

Test material form:

liquid

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 allowed an acclimatisation period of 26 days. The rabbits were individually housed in grid bottomed metal cages. A commercially available antibiotic free rabbit diet and mains drinking water via automatic nozzles in each cage were available ad libitum. The rabbit holding room was air-conditioned with temperature in the range of 15-23°C and relative humidity in the range of 46-91% during the acclimatisation and study periods. Fluorescent lighting was controlled to give an artificial cycle of 12 hours light/12 hours dark per day.

Test system

Type of coverage:

semiocclusive

Preparation of test site:

clipped

Vehicle:

unchanged (no vehicle)

Controls:

no

Amount / concentration applied:

0.5 mL

Duration of treatment / exposure:

4 hours

Observation period:

1, 24, 48, 72 hours and 7 days

Number of animals:

4 rabbits

Details on study design:

On the day of dosing, selected animals were placed in restraining stocks. 0.5 mL of the 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 one side of the flank and immediately caudal to the last rib, with the test material in contact with the skin.
The lint patch was held in place by encircling the trunk of the animal with a length of ‘Elastoplast’ elastic adhesive band-age 10cm wide. This also served as a semi-occlusive barrier to the treated skin. All rabbits were treated in this manner.
Animals remained in the restraining stocks during the dosing-period. After a period of four hours, the adhesive tape was removed and the treated site cleansed by gentle swabbing with cotton wool soaked in warm water. The animals were then returned to their cages.
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 24, 48 and 72 hours and 7 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 (score of 0 to 4 for erythema and eschar formation; score of 0 to 4 for edema formation). Other signs of reaction to treatment were fully described.

Results and discussion

In vivo

Results

Irritation parameter:

erythema score

Basis:

mean

Time point:

24/48/72 h

Score:

ca. 2.1

Max. score:

4

Reversibility:

not fully reversible within: 7 days

Irritant / corrosive response data:

Well defined erythema of the treated skin was observed in two animals and very slight erythema of the skin was noted at the treated site of the remaining two animals 1 hour after dosing. A score of 0.5 was given to edematous reaction observed at the treated site of 2 animals.
Well defined erythema was observed in all animals 24 hours after dosing. Slight edema was noted in one animal, very slight to slight edema was observed in a second animal, very slight edematous reaction was noted in one rabbit and a score of 0.5 was given to the edematous response observed at the treated site of the remaining animal.
Slight increase in both erythematous and edematous reaction was apparent in one animal at the 48 hour examination, edematous response in a second animal showing some decline.
72 hours after dosing, an increase in edematous reaction was apparent in two animals of the group, one of these animals now exhibiting slight edematous reaction and the second animal being given a score of 0.5 for edematous reaction at the treated site.
The irritant response described had declined within 7 days of dosing when very slight to well defined erythema remained in two animals and a score of 0.5 was given to erythematous reaction in the remaining two animals of the group. A score of 0.5 was given to the edematous response observed in two animals. Slight thickening of the treated skin was also observed in one animal at this time.

Any other information on results incl. tables

1 Hour Observation

Rabbit Number	Erythema	Oedema	Comments
1	1	0	None
2	2	0.5	None
3	2	0	None
4	1	0.5	None

 

24 Hours Observation

Rabbit Number	Erythema	Oedema	Comments
1	2	2	None
2	2	1.5	None
3	2	0.5	None
4	2	1	None

48 Hours Observation

Rabbit Number	Erythema	Oedema	Comments
1	2.5	2.5	None
2	2	1.5	None
3	2	0	None
4	2	1	None

 

72 Hours Observation

Rabbit Number	Erythema	Oedema	Comments
1	2.5	2.5	None
2	2	2	None
3	2	0.5	None
4	2	0.5	None

 

7 Days Observation

Rabbit Number	Erythema	Oedema	Comments
1	0.5	0	Slight thickening of skin
2	1.5	0.5	None
3	0.5	0	None
4	1.5	0.5	None

Applicant's summary and conclusion

Interpretation of results:

Category 3 (mild irritant) based on GHS criteria

Conclusions:

Under the test conditions, the test material is not classified as irritant to the skin according to the Annex VI of the Regulation (EC) No. 1272/2008 (CLP) and mild irritant (Category 3) to the skin according to the GHS regulation (Ninth revised version, 2021).

Executive summary:

The test material was applied, in 0.5 mL aliquot, over an area of approximately 6sq.cm. on the dorsal skin, clipped free of fur, of four albino rabbits. The material was held in contact with the skin under a semi-occlusive dressing for a four hour period after which time the patches were removed. Skin reaction to the material was assessed after one, twenty four, forty eight and seventy two hours and seven days.

Significant irritation of the treated skin was apparent following dosing, this response slowly declining.

The average irritation score was 2.1 and the average edema score was 1.3 for the test material. Therefore, the test substance requires a classification as skin irritant.

Under the test conditions, the test material is not classified as irritant to the skin according to the Annex VI of the Regulation (EC) No. 1272/2008 (CLP) and mild irritant (Category 3) to the skin according to the GHS regulation (Ninth revised version, 2021).