Fatty acids, C14-22, C16-24-alkyl esters

Skin sensitisation

Administrative data

Endpoint:

skin sensitisation: in vivo (non-LLNA)

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

01 Feb - 03 Apr 1995

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Remarks:

The results of the reliability check were inconclusive.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1995

Report date:

1995

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 406 (Skin Sensitisation)

Deviations:

yes

Remarks:

results of reliability check were inconclusive

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method B.6 (Skin Sensitisation)

Deviations:

yes

Remarks:

results of reliability check were inconclusive

GLP compliance:

yes

Type of study:

Buehler test

Justification for non-LLNA method:

Test was done before LLNA as first-choice method for in-vivo testing was set into force.

Test material

Test material information

Constituent 1

Reference substance name:

(Z)-octadec-9-enyl (Z)-docos-13-enoate

EC Number:

241-654-9

EC Name:

(Z)-octadec-9-enyl (Z)-docos-13-enoate

Cas Number:

17673-56-2

Molecular formula:

C40H76O2

IUPAC Name:

octadec-9-en-1-yl docos-13-enoate

In vivo test system

Test animals

Species:

guinea pig

Strain:

other: Dunkin Hartley Crl:(HA)BR

Sex:

female

Details on test animals and environmental conditions:

TEST ANIMALS
- Source: Charles River, Kisslegg, Germany
- Age at study initiation: approximately 5 weeks
- Weight at study initiation: approximately 380 g
- Housing: in groups of 2-3 animals in Makrolon Type IV cages (EBECO) with standard softwood bedding (ARWI-Center, Essen, Germany); bedding chaged twice weekly
- Diet: pelleted Altromin Maintenance Diet 3022 (Fa. Altromin, Lage, Germany), ad libitum. Carrots optionally added.
- Water: tap water, ad libitum
- Acclimation period: 7 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22 ± 3
- Humidity (%): 45-70
- Air changes (per hr): 100 m³
- Photoperiod (hrs dark / hrs light): 12/12

IN-LIFE DATES: 7 Feb - 3 Apr 1995

Study design: in vivo (non-LLNA)

Induction

Route:

epicutaneous, occlusive

Vehicle:

peanut oil

Concentration / amount:

70 %

Challenge

No.:

#1

Route:

epicutaneous, occlusive

Vehicle:

peanut oil

Concentration / amount:

60%

No. of animals per dose:

10 (control group), 20 (treatment group)

Details on study design:

RANGE FINDING TESTS:
Irritation test: 0.5 mL of the test substance was applied topically to the shaved skin of 3 guinea pigs, successively. A concentration of 12.5, 25, 50 and 100% was applied to the left flank and 30, 50 and 70% concentration to the right flank. The exposure was terminated after 6 hours by removing the plaster and cleaning the skin with 20% propylene glycol. The severity of erythema and oedema was assessed 24 and 48 h after exposure. The undiluted substance caused weak, confluent erythema in 1/3 animals at the 24 and 48 hour reading time point. The 70% solution was the lowest concentration to induce minimal irritation; causing weak, confluent erythema in 1/3 animals 24 hours after exposure. This effect had cleared within 48 hours.
Challenge test: the maximum non-irritating concentration was tested one week before the challenge in the main study by applying 0.5 mL of 30, 50 and 70% solution to the right flank of 5 animals in the control group under occlusive conditions. After 6 hours, the plaster was removed and the site cleaned with 20% propylene glycol. 24 and 48 hours after the exposure ended, the skin irritating effects were assessed. None of the concentrations caused skin irritation. 60% was selected to be the challenge dose.

MAIN STUDY
A. INDUCTION EXPOSURE
- No. of exposures: 3
- Exposure period: 6 h
- Test groups: test substance in peanut oil
- Control group: peanut oil
- Site: left cranial shaved flanks
- Frequency of applications: once weekly
- Duration: Day 1-14
- Concentrations: 70%

B. CHALLENGE EXPOSURE
- No. of exposures: 1
- Day(s) of challenge: 28
- Exposure period: 6 h
- Test groups: test substance in peanut oil
- Control group: test substance in peanut oil
- Site: left and right caudal flanks
- Concentrations: 60%
- Evaluation (hr after challenge): 24, 48 and 72 h

Positive control substance(s):

no

Results and discussion

Positive control results:

A reliability check is carried out at regular intervals with alpha-hexyl cinnamic aldehyde to check the sensitivity of the test system and the reliability of the experimental methods used by the test laboratory. An independent study was performed in October-December 1994 (report No. R 9400844), according to the Buehler method. During the first challenge with 25% alpha-hexyl cinnamic aldehyde, a sensitisation reaction was induced in 25% (5/20) of the Dunkin Hartley guinea pigs, while the second challenge did not lead to conclusive sensitisation reactions. In the negative control group, the first challenge induced sensitisation in 20% (2/10) of the animals, and the second challenge did not caused any sensitisation reactions. The 50% solution in peanut oil that was used for the topical inductions, caused weak to moderate skin irritation. A 25% solution was applied in the first challenge, while a 25% solution was applied to the left flank and 15, 20 and 25% solutions were applied to the right flank during the second challenge. As 20% of the animals in the negative control group reacted, the results of the reliability check are inconclusive.

In vivo (non-LLNA)

Results

Results 1

Key result

Reading:

1st reading

Hours after challenge:

24

Group:

negative control

Dose level:

Induction: 70%, Challenge: 60%

No. with + reactions:

1

Total no. in group:

10

Clinical observations:

1/10 animals showed slight, patchy erythema on the right flank only

Results 2

Key result

Reading:

1st reading

Hours after challenge:

24

Group:

test chemical

Dose level:

Induction: 70%, Challenge: 60%

No. with + reactions:

0

Total no. in group:

20

Results 3

Key result

Reading:

1st reading

Hours after challenge:

24

Group:

positive control

Dose level:

Induction: 50%; Challenge: 25%

No. with + reactions:

2

Total no. in group:

20

Remarks on result:

other: positive control in independent reliability check

Results 4

Key result

Reading:

2nd reading

Hours after challenge:

48

Group:

negative control

Dose level:

Induction: 70%, Challenge: 60%

No. with + reactions:

1

Total no. in group:

10

Clinical observations:

1/10 animals showed slight, patchy erythema on the left flank only

Results 5

Key result

Reading:

2nd reading

Hours after challenge:

48

Group:

test chemical

Dose level:

Induction: 70%, Challenge: 60%

No. with + reactions:

2

Total no. in group:

20

Clinical observations:

2/20 animals showed slight, patchy erythema on the left flank only

Results 6

Key result

Reading:

2nd reading

Hours after challenge:

48

Group:

positive control

Dose level:

Induction: 50%; Challenge: 25%

No. with + reactions:

5

Total no. in group:

20

Remarks on result:

other: positive control in independent reliability check

Results 7

Key result

Reading:

other: 3rd reading

Hours after challenge:

72

Group:

test chemical

Dose level:

Induction: 70%, Challenge: 60%

No. with + reactions:

0

Total no. in group:

20

Results 8

Key result

Reading:

other: 3rd reading

Hours after challenge:

72

Group:

negative control

Dose level:

Induction: 70%, Challenge: 60%

No. with + reactions:

0

Total no. in group:

10

Results 9

Key result

Reading:

other: 3rd reading

Hours after challenge:

72

Group:

positive control

Dose level:

Induction: 50%; Challenge: 25%

No. with + reactions:

1

Total no. in group:

20

Remarks on result:

other: positive control in independent reliability check

Any other information on results incl. tables

Skin rections, induction phases

The 3rd induction with a 70% solution caused slight skin irritation in 2/20 treatment animals.

Skin reactions, challenge phase

At the first reading, 1/10 control animals had slight, patchy erythema on the challenge site on the left flank. 1/10 in the control group had slight, patchy erythema on the right flank at the second reading, while 2/20 treatment animals had slight, patchy erythema on the left flank at the second reading. All skin irritation effects had cleared within 72 hours after exposure ended.

Table 1: Skin reactions 24, 48 and 72 hours after challenge

	24 hours		48 hours		72 hours
group (# of animals) flank	control (10) l/r	treatment (20) l/r	control (10) l/r	treatment (20) l/r	control (10) l/r	treatment (20) l/r
none	10/9	20/20	9/10	18/20	10/10	20/20
slight	0/1	0/0	1/0	2/0	0/0	0/0
weak	0/0	0/0	0/0	0/0	0/0	0/0
moderate	0/0	0/0	0/0	0/0	0/0	0/0
strong	0/0	0/0	0/0	0/0	0/0	0/0

l: left flank, induction site and challenge site

r: right flank, challenge site

Mortality and body weight

There was no mortality during the study period and the animals in the treatment group showed a similar gain in body weight compared with the control group.

Applicant's summary and conclusion

Interpretation of results:

other: CLP/EU GHS criteria not met, no classification required according to Regulation (EC) No 1272/2008