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Description of key information

Key value for chemical safety assessment

Skin sensitisation

Link to relevant study records
Reference
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: GLP guideline study
Qualifier:
according to
Guideline:
OECD Guideline 406 (Skin Sensitisation)
GLP compliance:
yes (incl. certificate)
Type of study:
guinea pig maximisation test
Species:
guinea pig
Strain:
other: Hsd Poc:DH (SPF)
Sex:
female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Harlan Winkelmann, Borchen, Germany
- Age at study initiation: approx. 3- 5 weeks
- Weight at study initiation: mean 305-330 g
- Housing: in groups of 2 or 3
- Diet and water: ad libitum
- Acclimation period: at least 7 days
Route:
intradermal and epicutaneous
Vehicle:
polyethylene glycol
Concentration / amount:
test substance formulated in polyethylene glycol 400 (PEG 400)
intradermal induction: 1% test item
epicutaneous induction: 100% test item
challenge: 25% test item
Route:
epicutaneous, semiocclusive
Vehicle:
polyethylene glycol
Concentration / amount:
test substance formulated in polyethylene glycol 400 (PEG 400)
intradermal induction: 1% test item
epicutaneous induction: 100% test item
challenge: 25% test item
No. of animals per dose:
test group: 10
control group: 5
Details on study design:
RANGE FINDING TESTS:
For intradermal induction: One guinea pig was given intradermal injections twice, in each case with 100 µl of the following test item concentrations: 0%, 1%, 2.5%, 5%. After evaluation (24, 48 hours) the concentration for the main test was set 1%.
For topical induction: 0%, 25%, 50% and 100% test substance formulations were tested in each case on four guinea pigs. After evaluation (48, 72 hours) the concentration for the main testing was set 100%.
For challenge: Four patches each loaded with 0.5 ml 0%, 12%, 25% and 50% test item formulation were applied to each of two guinea pigs. After evaluation (48, 72 hours) the concentration for the main testing was set 25%.

MAIN STUDY
A. INDUCTION EXPOSURE
The dorsal region and the flanks of the animals were shorn one day prior to the application.
Day 0: Three pairs of injections of 0.1 ml were given.
Injection 1: FCA/saline solution 1: 1
Injection 2: 1% test substance formulation
Injection 3: 1% test substance formulation in a mixture of equal parts with FCA
For control group animals the test substance was replaced by the same amount of PEG 400.

Day 7 - topical induction: On the day prior to topical treatment, the test areas of the animals were shorn. For topical treatment patches loaded with 0.5 ml 100% test item (test group) or with dry patches (control group) were applied, covered with aluminium foil and held securely in place using a self-adhesive tape. At the end of the 48h-exposure period, the remaining test item was removed with saline solution.

B. CHALLENGE EXPOSURE
The challenge was performed three weeks after the intradermal induction. One day prior to challenge the dorsal region and the left flank of the anials were shorn. During the challenge a hypoallergenic patch loaded with0.5 ml 25% test item formulation was applied to the animals of the test and control group and securely held in place with a self-adhesive tape for 24 hours. A patch loeded only with the vehicle was also applied as control. At the end of the exposure period, the remaining test item was removed with saline solution. 21 hours later the skin of the animals was shorn in the zone of the challenge area.
Positive control substance(s):
yes
Remarks:
2-mercaptobenzothiazole
Reading:
1st reading
Hours after challenge:
48
Group:
test group
Dose level:
25 %
No. with + reactions:
0
Total no. in group:
10
Remarks on result:
other: Reading: 1st reading. . Hours after challenge: 48.0. Group: test group. Dose level: 25 %. No with. + reactions: 0.0. Total no. in groups: 10.0.
Reading:
2nd reading
Hours after challenge:
72
Group:
test group
Dose level:
25 %
No. with + reactions:
0
Total no. in group:
10
Remarks on result:
other: Reading: 2nd reading. . Hours after challenge: 72.0. Group: test group. Dose level: 25 %. No with. + reactions: 0.0. Total no. in groups: 10.0.
Reading:
1st reading
Hours after challenge:
48
Group:
negative control
Dose level:
25%
No. with + reactions:
0
Total no. in group:
5
Remarks on result:
other: Reading: 1st reading. . Hours after challenge: 48.0. Group: negative control. Dose level: 25%. No with. + reactions: 0.0. Total no. in groups: 5.0.
Reading:
2nd reading
Hours after challenge:
72
Group:
negative control
Dose level:
25%
No. with + reactions:
0
Total no. in group:
5
Remarks on result:
other: Reading: 2nd reading. . Hours after challenge: 72.0. Group: negative control. Dose level: 25%. No with. + reactions: 0.0. Total no. in groups: 5.0.

At day 9, directly after removal of the patch of the second induction, the treatment area showed skin effects grade 1 in 2/10 animals in the test item group and no effects in the control group.

Appearance and behaviour of the test item group were not different from the control group.

Executive summary:

A guinea pig maximisation test (Magnusson and Kligman) was conducted with the test item according to OECD TG 406. In this study the substance was injected intracutaneously in 10 guinea pigs at a 1 % concentration in polyethylene glycol (PEG) including Freund’s Complete Adjuvant. After 7 days topical induction was performed with a 100 % test item concentration. Three weeks after the intradermal induction the challenge experiment was conducted with 25 % test item. The challenge led to no skin effects in the animals of the treated group or the control group. Therefore, under the conditions of the study the test substance was concluded to be non-skin sensitising.

Endpoint conclusion
Endpoint conclusion:
no adverse effect observed (not sensitising)
Additional information:

A guinea pig maximisation test (Magnusson and Kligman) was conducted with the test item according to OECD TG 406. In this study the substance was injected intracuteanously in 10 Guinea pigs at a 1 % concentration in polyethylene glycol (PEG) including Freund’s complete adjuvant. After 7 days the topical induction was performed with a 100 % test item concentration. Three weeks after the intradermal induction the challenge experiment was carried out with 25 % test item. The challenge led to no skin effects in the animals of the treated group or the control group. Therefore, under the conditions of the study the test substance was concluded to be non-skin sensitising.


Justification for selection of skin sensitisation endpoint:
Only one study available

Respiratory sensitisation

Endpoint conclusion
Endpoint conclusion:
no study available

Justification for classification or non-classification

No classification required for skin sensitisation according to Regulation (EC) No 1272/2008, Annex I.