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Administrative data

Endpoint:
skin sensitisation: in vivo (non-LLNA)
Type of information:
experimental study
Adequacy of study:
key study
Study period:
20 May 1999 - 24 June 1999
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: GLP-compliant guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1999
Report date:
1999

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to guideline
Guideline:
OECD Guideline 406 (Skin Sensitisation)
Qualifier:
according to guideline
Guideline:
EU Method B.6 (Skin Sensitisation)
Qualifier:
according to guideline
Guideline:
EPA OPPTS 870.2600 (Skin Sensitisation)
GLP compliance:
yes
Type of study:
Buehler test

Test material

Constituent 1
Chemical structure
Reference substance name:
4-[(1-butyl-5-cyano-1,6-dihydro-2-hydroxy-4-methyl-6-oxo-3-pyridyl)azo]-N-(2-ethylhexyl)benzenesulphonamide
EC Number:
259-571-1
EC Name:
4-[(1-butyl-5-cyano-1,6-dihydro-2-hydroxy-4-methyl-6-oxo-3-pyridyl)azo]-N-(2-ethylhexyl)benzenesulphonamide
Cas Number:
55290-62-5
Molecular formula:
C25H35N5O4S
IUPAC Name:
4-[(1-butyl-5-cyano-2-hydroxy-4-methyl-6-oxo-1,6-dihydropyridin-3-yl)diazenyl]-N-(2-ethylhexyl)benzenesulfonamide
Details on test material:
- Physical state: yellow powder

In vivo test system

Test animals

Species:
guinea pig
Strain:
Dunkin-Hartley
Sex:
female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: D. Hall, Newchurch, Staffordshire, England
- Age at study initiation: four to seven weeks
- Weight at study initiation: 365 - 428 g
- Housing: in groups of five in suspended metal cages with wire mesh floors
- Diet: vitamin C enriched guinea-pig diet (Harlan Teklad 9600 FD2 SQC), ad libitum
- Water: drinking water, ad libitum
- Acclimation period: five days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 17.5 to 28.0°C
- Humidity (%): 37 to 64%
- Photoperiod (hrs dark / hrs light): 12/12

Study design: in vivo (non-LLNA)

Inductionopen allclose all
Route:
epicutaneous, occlusive
Vehicle:
other: Alembicol D (A product of coconut oil, supplied by Alembic Products)
Concentration / amount:
Based on the results of the preliminary investigations, the following concentrations were selected:
Induction topical application - 55% w/v in Alembicol D
Topical challenge - 55% w/v in Alembicol D
Challengeopen allclose all
Route:
epicutaneous, occlusive
Vehicle:
other: Alembicol D (A product of coconut oil, supplied by Alembic Products)
Concentration / amount:
Based on the results of the preliminary investigations, the following concentrations were selected:
Induction topical application - 55% w/v in Alembicol D
Topical challenge - 55% w/v in Alembicol D
No. of animals per dose:
For the main test, twenty test and ten control animals were used. An additional four animals from the same supplier were used for the preliminary investigations.
Details on study design:
RANGE FINDING TESTS:
The topical irritancy of a range of dilutions of the test substance was investigated to identify where possible (a) concentrations of the test substance that would produce irritation suitable for the induction phase of the main study and (b) a maximum non-irritant concentration for the challenge phase. Approximately 0.5 ml of a range of concentrations (10 to 55% w/v) in a suitable vehicle (Alembicol D) was applied to patches of surgical gauze (20 x 20 mm). These were placed occlusively on the clipped and shaved flanks of each of four guinea-pigs. After an exposure period of approximately six hours the dressings were removed and the reaction sites were assessed for erythema and oedema. Further examination of the sites was carried out approximately 24 and 48 hours after removal of the dressings.

MAIN STUDY
A. INDUCTION EXPOSURE
Prior to each induction application, the skin on the left shoulder region of the guinea-pig was clipped free of hair using electric clippers. A 20 x 20 mm patch of surgical gauze (three layers thick) was saturated with approximately 0.5 ml of the test article 55% w/v in Alembicol D. The patch was placed on the skin and covered by a length of impermeable plastic adhesive tape (50 mm width "Blenderm"). This in turn was firmly secured by elastic adhesive bandage (50 mm width "Elastoplast") wound round the torso of the animals and fixed with "Sleek" impervious plastic adhesive tape. Contact with the skin was maintained for approximately 6 hours for each induction exposure. The dressings were then removed and the resulting dermal reactions assessed approximately 24 hours later. One induction application was made in this manner on Days 1, 8 and 15 so a total of three induction applications were made.
During the induction phase, the control animals were treated similarly to the test animals with the exception that the test substance was omitted from the induction applications.

B. CHALLENGE EXPOSURE
The control and test animals were challenged topically two weeks after the final induction application using the test article, 55% w/v in Alembicol D. Hair was removed by clipping and then shaving from a 50 x 50 mm area on the right flank of each guinea-pig. A 20 x 20 mm surgical gauze patch was saturated with approximately 0.5 ml of the test substance, 55% w/v in Alembicol D and applied to the flank in a similar manner to the induction applications. The patches were sealed to the flank under strips of "Blenderm" covered by "Elastoplast" wound round the trunk and secured with "Sleek". Dressings were left in place for approximately 6 hours after which time they were removed.
Positive control substance(s):
yes
Remarks:
The sensitivity of the guinea-pig strain used is checked periodically at Huntingdon Life Sciences with known sensitisers hexyl cinnamic aldehyde (HCA) or 2-mercaptobenzothiazole (MBT).

Results and discussion

In vivo (non-LLNA)

Resultsopen allclose all
Reading:
1st reading
Hours after challenge:
24
Group:
test chemical
Dose level:
55%
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: 55%. No with. + reactions: 0.0. Total no. in groups: 20.0.
Reading:
2nd reading
Hours after challenge:
48
Group:
test chemical
Dose level:
55%
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: 55%. No with. + reactions: 0.0. Total no. in groups: 20.0.
Reading:
1st reading
Hours after challenge:
24
Group:
negative control
Dose level:
55%
No. with + reactions:
0
Total no. in group:
10
Remarks on result:
other: Reading: 1st reading. . Hours after challenge: 24.0. Group: negative control. Dose level: 55%. No with. + reactions: 0.0. Total no. in groups: 10.0.
Reading:
2nd reading
Hours after challenge:
48
Group:
negative control
Dose level:
55%
No. with + reactions:
0
Total no. in group:
10
Remarks on result:
other: Reading: 2nd reading. . Hours after challenge: 48.0. Group: negative control. Dose level: 55%. No with. + reactions: 0.0. Total no. in groups: 10.0.

Any other information on results incl. tables

CLINICAL SIGNS

No signs of ill health or toxicity were observed.

BODYWEIGHT

Bodyweight increases were recorded for all guinea-pigs over the period of the study.

INDUCTION

There were no dermal reactions seen in any of the test or control animals.

CHALLENGE

There were no dermal reactions seen in any of the test or control animals, therefore all twenty test animals gave negative responses.

Applicant's summary and conclusion

Interpretation of results:
not sensitising
Remarks:
Migrated information Criteria used for interpretation of results: EU
Conclusions:
The test article did not produce evidence of skin sensitization (delayed contact hypersensitivity) in any of the twenty test animals.
Executive summary:

A Buehler Test following OECD guideline 406 was performed to assess the skin sensitization potential of the test article using the guinea-pig. Based on the results of a preliminary study and in compliance with the guidelines, the following dose levels were selected: Topical application: 55% w/v in Alembicol D; Challenge application: 55% w/v in Alembicol D. Twenty test and ten control guinea-pigs were used in this study. In this study the test article did not produce evidence of skin sensitization (delayed contact hypersensitivity) in any of the twenty test animals.