Registration Dossier

Administrative data

Endpoint:
skin sensitisation: in vivo (non-LLNA)
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: This study was selected as the key study because the information provided for the hazard endpoint is sufficient for the purpose of classification and labelling and/or risk assessment.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1998
Report Date:
1998

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
OECD Guideline 406 (Skin Sensitisation)
Deviations:
no
Remarks:
The study was conducted according to the guideline in effect at the time of study conduct.
Qualifier:
according to
Guideline:
EPA OPP 81-6 (Skin Sensitisation)
Deviations:
no
Remarks:
The study was conducted according to the guideline in effect at the time of study conduct.
GLP compliance:
yes
Type of study:
guinea pig maximisation test

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Purity: 99.7%

In vivo test system

Test animals

Species:
guinea pig
Strain:
Dunkin-Hartley
Sex:
female
Details on test animals and environmental conditions:
TEST ANIMALS
- Age at study initiation: Young adults
- Weight at study initiation: 380-486 g
- Housing: five per cage in cages suitable for animals of this strain and the weight range expected during the course of the study
- Diet (e.g. ad libitum): ad libitum
- Water (e.g. ad libitum): ad libitum

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20±3°C
- Humidity (%): 30-70%
- Air changes (per hr): 15 changes/hour
- Photoperiod (hrs dark / hrs light): Artificial, giving 12 hours light, 12 hours dark

Study design: in vivo (non-LLNA)

Inductionopen allclose all
Route:
intradermal and epicutaneous
Vehicle:
other: corn oil or Freund's Complete Adjuvant
Concentration / amount:
Induction Phase (each animal received three injections plus a week later, the topical application)
Injection 1: Freund's Complete Adjuvant plus corn oil in the ratio 1:1
Injection 2: 10% w/v preparation of the test substance in corn oil
Injection 3: 10% w/v preparation of the test substance in Freund's Complete Adjuvant plus corn oil in the ratio 1:1
Topical Application: 0.2-0.3 mL undiluted test substance

Challenge Phase (each animal received the 2 topical applications)
Topical Application: 0.05-0.1 mL undiluted test substance
Topical Application: 0.05-0.1 mL 75% test substance in corn oil
Challengeopen allclose all
Route:
epicutaneous, occlusive
Vehicle:
other: corn oil or Freund's Complete Adjuvant
Concentration / amount:
Induction Phase (each animal received three injections plus a week later, the topical application)
Injection 1: Freund's Complete Adjuvant plus corn oil in the ratio 1:1
Injection 2: 10% w/v preparation of the test substance in corn oil
Injection 3: 10% w/v preparation of the test substance in Freund's Complete Adjuvant plus corn oil in the ratio 1:1
Topical Application: 0.2-0.3 mL undiluted test substance

Challenge Phase (each animal received the 2 topical applications)
Topical Application: 0.05-0.1 mL undiluted test substance
Topical Application: 0.05-0.1 mL 75% test substance in corn oil
No. of animals per dose:
Test substance - 20
Control - 10
Details on study design:
MAIN STUDY
A. INDUCTION EXPOSURE
An area approximately 5 x 5 cm on the scapular region of each animal was clipped free of hair with a pair of veterinary clippers and a row of three injections (0.05-0.1 mL each) was made on each side of the mid-line. The injections were:

i) Top: Freund's Complete Adjuvant plus corn oil in the ratio 1: 1;
ii) Middle: a 10% w/v preparation of the test substance in corn oil;
iii) Bottom: a 10% w/v preparation of the test substance in a 1: 1 preparation of Freund's Complete Adjuvant plus corn oil.

Control animals were treated the same as the test animals, except that they were treated with corn oil in place of the test substance. The injections were checked for any adverse effects approximately 1 day after dosing. One week after intradermal injection, the scapular area was clipped again and treated with a topical application of the undiluted test substance. This preparation (0.2-0.3 mL) was applied on filter paper (approximate size 4 cm x 2 cm) which was held in place by a piece of surgical tape. The tape was covered by a strip of adhesive bandage (approximate size 20-30 cm x 5 cm) and secured by a piece of self-adhesive PVC tape. This occlusive dressing was kept in place for at least 48 hours. Control animals were similarly treated except that the test substance was not applied to the filter paper. The application sites were checked approximately 1 day after removal of the dressings, and twice further prior to challenge.

B. CHALLENGE EXPOSURE
Two weeks after the topical inductions, an area, approximately l5 cm x 5 cm, on both flanks of all the test and control animals, was clipped free of hair with a pair of veterinary clippers. An occlusive dressing was prepared which consisted of two pieces of filter paper (approximate size l cm x 2 cm) stitched to a piece of rubber sheeting (approximate size l2 cm x 5 cm). The undiluted test substance (0.05-0.l mL) was applied to one of the pieces of filter paper and a 75% w/v preparation in com oil (0.05-0.l mL) was applied to the second piece of filter paper. The dressing was placed on the shorn flank of the guinea pig so that the undiluted test substance was on the left and the 75% w/v preparation was on the right. It was then covered with a strip of adhesive bandage (approximate size 25-40 cm x 7.5 cm) which was secured by a self-adhesive PVC tape. After at least 24 hours, the dressings were carefully cut, using blunt-tipped scissors, removed and discarded. The position of the pieces of filter paper on the skin were identified using a black waterproof marker-pen. Skin sites were examined approximately I and 2 days after removal of the dressings.
Positive control substance(s):
yes
Remarks:
A positive control study using hexylcinnamaldehyde was carried out at approximately 6 month intervals to ensure that the test system continued to respond to known sensitizers.

Results and discussion

Positive control results:
The net percentage response was calculated to be 65% and, under the conditions of the test, hexylcinnamaldehyde was classified as a strong skin sensitizer.

In vivo (non-LLNA)

Resultsopen allclose all
Reading:
1st reading
Hours after challenge:
24
Group:
test group
Dose level:
undiluted
No. with + reactions:
0
Total no. in group:
20
Remarks on result:
other: Reading: 1st reading. . Hours after challenge: 24.0. Group: test group. Dose level: undiluted. No with. + reactions: 0.0. Total no. in groups: 20.0.
Reading:
1st reading
Hours after challenge:
24
Group:
test group
Dose level:
75%
No. with + reactions:
0
Total no. in group:
20
Remarks on result:
other: Reading: 1st reading. . Hours after challenge: 24.0. Group: test group. Dose level: 75% . No with. + reactions: 0.0. Total no. in groups: 20.0.
Reading:
2nd reading
Hours after challenge:
48
Group:
test group
Dose level:
undiluted
No. with + reactions:
0
Total no. in group:
20
Remarks on result:
other: Reading: 2nd reading. . Hours after challenge: 48.0. Group: test group. Dose level: undiluted. No with. + reactions: 0.0. Total no. in groups: 20.0.
Reading:
2nd reading
Hours after challenge:
48
Group:
test group
Dose level:
75%
No. with + reactions:
0
Total no. in group:
20
Remarks on result:
other: Reading: 2nd reading. . Hours after challenge: 48.0. Group: test group. Dose level: 75%. No with. + reactions: 0.0. Total no. in groups: 20.0.

Any other information on results incl. tables

Slight erythema was observed in test animals following intradermal induction.

Applicant's summary and conclusion

Interpretation of results:
not sensitising
Remarks:
Migrated information Criteria used for interpretation of results: expert judgment
Conclusions:
This study and the conclusions which are drawn from it fulfil the quality criteria (validity, reliability, repeatability).

The test substance is not sensitising in the guinea pig Maximisation Test.
Executive summary:

The skin sensitization potential of the test substance was assessed in a group of 20 guinea pigs. For the induction phase, the test substance was dosed intradermally as a 10% w/v preparation in corn oil (with or without Freund's Complete Adjuvant) and a week later, as an undiluted topical application. Two weeks after the topical induction the challenge phase was conducted with a topical application of a 75% test substance preparation in corn oil and undiluted test substance. Skin treatment sites were examined 24 hours later.

Slight erythema was seen in the test animals following intradermal induction. Following challenge of the induced guinea pigs with the test substance, there was no erythematous response in any of the test or control animals. The test substance was not a sensitizer under the conditions of the test.