Reaction products of 7-hydroxy-3,7-dimethyloctanal and methyl 2-aminobenzoate

Skin irritation / corrosion

Administrative data

Endpoint:

skin irritation: in vivo

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

13 August 1979 to 26 September 1979

Reliability:

4 (not assignable)

Rationale for reliability incl. deficiencies:

other: Older study conducted prior to development of GLP and current test guideline; methodology is not comparable to current guidelines.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1979

Report date:

1979

Materials and methods

Test guideline

Qualifier:

no guideline followed

Principles of method if other than guideline:

The study was conducted prior to adoption of OECD test guidelines. A single semi-occluded 4-hour topical application was made to the dorsum of eight rabbits; the reactions were assessed at 24, 48 and 72 hours post application. Whilst the application method is similar to current guidelines, a non-standard scoring system was used and observations were not made beyond 72 hours, therefore this study is not considered to be comparable to current guidelines.

GLP compliance:

no

Remarks:

Conducted prior to development of GLP

Test material

Test material information

Constituent 1

Reference substance name:

Reaction products of 7-hydroxy-3,7-dimethyloctanal and methyl 2-aminobenzoate

IUPAC Name:

Reaction products of 7-hydroxy-3,7-dimethyloctanal and methyl 2-aminobenzoate

Constituent 2

Reference substance name:

Aurantoin

IUPAC Name:

Aurantoin

Test material form:

liquid: viscous

Details on test material:

- Name of test material (as cited in study report): Aurantoin, use described as perfumery material
- Physical state: Clear, yellow viscous liquid

Test animals

Species:

rabbit

Strain:

New Zealand White

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Age at study initiation: 9-12 weeks

Test system

Type of coverage:

semiocclusive

Preparation of test site:

clipped

Vehicle:

unchanged (no vehicle)

Controls:

yes

Amount / concentration applied:

0.5 mL of undiluted test substance was applied to the clipped dorsum of each rabbit.

Duration of treatment / exposure:

4 hours

Observation period:

Observations were made immediately after removal of the patch, and 24, 48 and 72 hours after application.

Number of animals:

Eight rabbits (one test substance and three reference controls applied to randomised sites on the rabbits).

Details on study design:

TEST SITE:
- Area of exposure: 2.5 x 2.5 cm patch on dorsum
- Type of wrap if used: The patches were prepared by attaching a piece of thin flexible polythene (3 cm x 3 cm) to a piece of zinc oxide plaster (9 cm x 2.5 cm). A 2.5 cm square of cotton gauze (8-ply folded in two) was placed onto the polythene so that the edges of the pad were attached to the plaster. The test substance was applied directly to the dry patch. The patches were firmly attached and the animals immobilised during exposure.

REMOVAL OF TEST SUBSTANCE
- Washing (if done): The treatment sites were wiped clean of excess test substance at patch removal
- Time after start of exposure: 4 hours

SCORING SYSTEM: An eight point anchored ordinate scale was used (see below). The test sites were scored for erythema, oedema, cracking, scaling, scabbing, presence of exudate and haemorrhage.
a = marginal/very slight; 1 point
b = slight; 2 points
c = fairly distinct; 3 points
d = quite distinct; 4 points
e = becoming well developed; 6 points
f = well developed; 8 points
g = becoming severe; 10 points
h = severe; 12 points

Results and discussion

In vivo

Results

Results 1

Irritation parameter:

erythema score

Basis:

mean

Time point:

24/48/72 h

Score:

31

Max. score:

288

Reversibility:

not specified

Results 2

Irritation parameter:

edema score

Basis:

mean

Time point:

24/48/72 h

Score:

25

Max. score:

288

Reversibility:

not specified

Irritant / corrosive response data:

Marginal/slight erythema was observed in 3 animals at patch removal; 3 animals exhibited slight erythema whilst 2 animals exhibited fairly distinct erythema. Four animals exhibited marginal/very slight oedema at this time point, with 3 animals exhibiting slight oedema and the 1 remaining animal exhibiting fairly distinct oedema.
The test site of 1 rabbit had returned to normal 24 hours after application. Six rabbits exhibited marginal/very slight to slight erythema and oedema at 24 hours, the remaining rabbit exhibited erythema that was 'becoming well developed' and quite distinct erythema.
By the 48 hour observation, a second rabbit was no longer displaying signs of irritation. Five rabbits were displaying marginal/very slight erythema, and no reaction to marginal/very slight oedema. One of these rabbits also displayed marginal/very slight cracking of the skin. The remaining rabbit exhibited quite distinct erythema and 'becoming well developed' oedema.
At the 72 hour observation, 5 rabbits were free of erythema and oedema however 3 of these rabbits exhibited marginal/very slight cracking of the skin. Two rabbits still exhibited marginal/very slight erythema and oedema, with one rabbit exhibiting quite distinct erythema and oedema.

Other effects:

Pale yellow discolouration was observed in 5 animals at patch removal. The irritant response produced by the test substance, aurantiol pure, was greater than that produced by diethyl phthalate, but less than that produced by cyclamen aldehyde and geraniol.

Any other information on results incl. tables

Table 1: Skin irritation results

Rabbit No.	Time after application
	4 hours (patch removal)			24 hours			48 hours			72 hours
	E	O	C	E	O	C	E	O	C	E	O	C
1	b*	a	-	a	-	-	-	-	-	-	-	a
2	b*	b	-	-	-	-	-	-	-	-	-	-
3	c*	c	-	b	b	-	a	-	-	-	-	-
4	a*	b	-	a	a	-	a	a	-	-	-	a
5	c*	b	-	e	d	-	d	e	-	d	d	a
6	a	a	-	b	b	-	a	a	-	a	-	-
7	a	a	-	b	a	-	a	-	a	-	-	a
8	b	a	-	b	a	-	a	a	-	a	a	-

E = erythema; O = oedema; C = cracking.

* = pale yellow discolouration of test site; - = no reaction observed

Scoring System:

a = marginal/very slight = 1

b = slight = 2

c = fairly distinct = 3

d = quite distinct = 4

e = becoming well developed = 6

f = well developed = 8

g = becoming severe = 10

h = severe = 12

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Remarks:

Criteria used for interpretation of results: EU

Conclusions:

Aurantoin caused slight irritation in rabbits following a 4-hour semi-occlusive exposure but insufficient for classification.

Executive summary:

The skin irritation potential of aurantiol pure was evaluated in New Zealand White rabbits. The study design and scoring method are not comparable to current OECD test guidelines. The test substance was applied to the clipped dorsal skin of 8 rabbits, and held in place under a semi-occlusive dressing for four hours. Each rabbit also received applications of 3 reference substances, simultaneously (diethyl phthalate, cyclamen aldehyde and geraniol). After the exposure period, the patches were removed and residual test substance was removed by wiping. Skin reactions were scored immediately after patch removal, then at 24, 48 and 72 hours after application. Reactions (erythema, oedema, cracking, scaling, scabbing, exudant and haemorrhage) were graded according to an 8-point anchored ordinate scale, ranging from ‘very slight’ to ‘severe’. The test substance caused marginal/slight to slight erythema in 7 rabbits, with 1 rabbit exhibiting quite distinct to becoming well developed erythema and oedema. Cracking of the skin of the test site was observed in 1 rabbit at the 48 hour observation, and in 4 rabbits at the 72 hour observation. With the exception of 1 rabbit, reactions appeared to ameliorate between the 24 and 72 hour observations. Erythema and oedema persisted in 3 rabbits at the 72 hour time point; as no further observations took place it is not possible to conclude on reversibility of reactions. The irritant response produced by the test substance, aurantiol pure, was greater than that produced by diethyl phthalate, but less than that produced by cyclamen aldehyde and geraniol. It can be concluded that the test substance was slightly irritating to rabbit skin.