Octanoic acid

Skin irritation / corrosion

Administrative data

Endpoint:

skin irritation: in vivo

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1984

Report date:

1984

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 404 (Acute Dermal Irritation / Corrosion)

Version / remarks:

1981

Deviations:

no

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Octanoic acid

EC Number:

204-677-5

EC Name:

Octanoic acid

Cas Number:

124-07-2

Molecular formula:

C8H16O2

IUPAC Name:

octanoic acid

Test animals

Species:

rabbit

Strain:

New Zealand White

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Van Zutphen Breeding Centre, Keldonk, The Netherlands
- Weight at study initiation: 2779 g, 2886 g and 2949 g (measured 5 days before dose administration)
- Housing: individually in metal cages with perforated floors
- Diet: standard laboratory animal diet (LK-01, pellet diameter 4 mm)
- Water: tap water, ad libitum
- Acclimation period: at least 5 days


ENVIRONMENTAL CONDITIONS
- Temperature (°C): 17-22
- Humidity (%): 50-75
- Photoperiod (hrs dark / hrs light): 12/12

Test system

Type of coverage:

semiocclusive

Preparation of test site:

other: clipped

Vehicle:

unchanged (no vehicle)

Controls:

other: untreated skin sites of same animals

Amount / concentration applied:

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 0.5 mL
- Concentration: 100%

Duration of treatment / exposure:

4 h

Observation period:

14 days
Reading time points: 1, 24, 48 and 72 h

Number of animals:

3

Details on study design:

TEST SITE
- Area of exposure: right flank
- Type of wrap if used: 6 cm patch of surgical gauze, which was attached with a bit of petrolatum to aluminium foil and mounted on tape (Micropore@, 3M, St. Paul, USA). Finally, the animals were wrapped in flexible bandage (Coban@, 3M, St. Paul, USA).


REMOVAL OF TEST SUBSTANCE
- Washing (if done): no, removal of substance by tissue
- Time after start of exposure: 4 h


SCORING SYSTEM:
Erythema:
0 - no erythema
1 - very slight erythema (barely pereptible)
2 - well-defined erythema
3 - moderate to severe erythema
4 - severe erythema (beet redness) to slight eschar formation (injuries in deep)

edema:
0 - no edema
1- very slight edema (barely perceptible)
2 - slight edema (edges of area well defined by definite raising)
3 - moderate edema (raised appr. 1 mm)
4 - severe edema (raised >1 mm and extending beyond area of exposure)

Results and discussion

In vivo

Results

Results 1

Irritation parameter:

erythema score

Basis:

animal #1

Time point:

24/48/72 h

Score:

3

Max. score:

4

Reversibility:

not fully reversible within: 14 days

Results 2

Irritation parameter:

erythema score

Basis:

animal #2

Time point:

24/48/72 h

Score:

3

Max. score:

4

Reversibility:

not fully reversible within: 14 days

Results 3

Irritation parameter:

erythema score

Basis:

animal #3

Time point:

24/48/72 h

Score:

3

Max. score:

4

Reversibility:

not fully reversible within: 14 days

Results 4

Irritation parameter:

edema score

Basis:

animal #1

Time point:

24/48/72 h

Score:

2.7

Max. score:

4

Reversibility:

not fully reversible within: 14 days

Results 5

Irritation parameter:

edema score

Basis:

animal #2

Time point:

24/48/72 h

Score:

1.3

Max. score:

4

Reversibility:

not fully reversible within: 14 days

Results 6

Irritation parameter:

edema score

Basis:

animal #3

Time point:

24/48/72 h

Score:

1.3

Max. score:

4

Reversibility:

not fully reversible within: 14 days

Results 7

Irritation parameter:

other: necrosis

Basis:

animal: #1, #2, #3

Time point:

48 h

Reversibility:

not reversible

Remarks on result:

other: full thickness necrosis was observed at reading time point 48 h in all animals

Irritant / corrosive response data:

Only slight edema and moderate erythema were observed 1, 24, 48, and 72 h after removal of the test material. However, the also observed light-brown staining of the skin proved to indicate skin necrosis, since a crust had formed 48 h after exposure.
In one animal the hairs in the exposed area continued to grow, indicating that the hair roots, lying in the deeper layers of the dermis, had not been affected in this animal. The other two animals revealed no hair growth in the treated area. On day 7, in each of the animals the hairs failed to grow. After the formation and loosening of the crust, the skin had almost returned to normal 14 days after exposure in the two animals, while the one animal showed a rather scurfy skin and only partial restoration of hair growth.
In conclusion, since the test material produced full thickness destruction of the skin tissue in the treated animals, the test material is considered to be corrosive.

Any other information on results incl. tables

Results:

Time	Animal	Erythema	Edema	Other findings
1 h	1	1	2
	2	1	1	b
	3	1	1	b
24 h	1	1	3	b
	2	1	2	b
	3	1	2	b
48 h	1	4	2	n
	2	4	2	n
	3	4	2	n
72 h	1	4	0	e
	2	4	0	e
	3	4	0	e
mean 24 - 48 - 72 h	1	3.0	2.7
	2	3.0	1.3
	3	3.0	1.3
mean		3.0	1.8

b: exposed skin brownish

n: skin necrotic

e: eschar formation

Applicant's summary and conclusion

Interpretation of results:

other: classification as Skin Corr. 1C, H314 required according to Regulation (EC) No 1272/2008

Conclusions:

CLP: Skin Corr. 1C, H314