Registration Dossier

Diss Factsheets

Toxicological information

Skin sensitisation

Currently viewing:

Administrative data

Endpoint:
skin sensitisation: in vivo (non-LLNA)
Type of information:
experimental study
Adequacy of study:
key study
Study period:
1997-02-20 to 1997-04-29
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1997
Report date:
1997

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to guideline
Guideline:
EU Method B.6 (Skin Sensitisation)
Deviations:
no
Qualifier:
according to guideline
Guideline:
OECD Guideline 406 (Skin Sensitisation)
Version / remarks:
1992
Deviations:
no
GLP compliance:
yes (incl. QA statement)
Type of study:
guinea pig maximisation test
Justification for non-LLNA method:
The in vivo study was initiated before the entry into force of the amendments to Annexes VII and VIII

Test material

Constituent 1
Chemical structure
Reference substance name:
-
EC Number:
429-100-6
EC Name:
-
Cas Number:
23911-56-0
Molecular formula:
C11H10O2
IUPAC Name:
1-(3-methyl-1-benzofuran-2-yl)ethan-1-one

In vivo test system

Test animals

Species:
guinea pig
Strain:
Dunkin-Hartley
Sex:
male
Details on test animals and environmental conditions:
TEST ANIMALS
- Microbiological status of animals: SPF
- Age at study initiation: Adult
- Weight at study initiation: 351-400 g
- Housing: The guinea pigs were housed in polycarbonate (macrolone type IV, floor area 1800 cm2) cages with softwood bedding, two or three to a cage. The cages were cleaned and the bedding changed 3 times a week.
- Diet: Ad libitum
- Water: Ad libitum
- Acclimation period: 5 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 21 ± 3
- Humidity (%): 55 ± 15
- Air changes (per hr): 10
- Photoperiod (hrs dark / hrs light): 12/12

- IN-LIFE DATES: From day 0 to day 23

Study design: in vivo (non-LLNA)

Induction
Route:
intradermal and epicutaneous
Vehicle:
arachis oil
Remarks:
Arachis oil and Ethanol/diethylphthlate 1:1
Concentration / amount:
6% (w/w)
Day(s)/duration:
3 weeks: Intradermal injections on day 0, topical sodium lauryl sulphate treatment on day 6, topical treatment with 50% test article on day 7 until dressing was removed on day 9, another 11 days until challenge
Adequacy of induction:
highest concentration used causing mild-to-moderate skin irritation and well-tolerated systemically
Challenge
No.:
#1
Route:
epicutaneous, occlusive
Vehicle:
other: ethanol/diethylphthlate 1:1
Concentration / amount:
25%
Day(s)/duration:
Day 20 (duration = 1 day)
Adequacy of challenge:
highest non-irritant concentration
No. of animals per dose:
20 male animals for a single dose
Details on study design:
RANGE FINDING TESTS:
The irritancy of the test article was investigated in order to find the minimal irritant test article concentration for the intradermal induction and the maximum non-irritating test article concentration for the challenge application. Intradermal irritancy was tested after 4 injections of test concentrations between 6% and 50% (w/w). After 48 hours, a test concentration of 6% (w/w) induced slight erythema whereas higher concentrations induced erythema and the highest concentration induced necroses. Topical irritancy was tested using the same concentrations. No skin reactions were noticed except the occurence of slight erythema in one animal at a concentration of 50% (w/w) after 48 hours. Thus, a concentration of 6% (w/w) was chosen for induction treatment and 50% (w/w) was chosen for challenge application.

MAIN STUDY
A. INDUCTION EXPOSURE
- No. of exposures: 2 (intradermal injections and a closed patch topical application)
- Exposure period: 3 weeks (including the closed patch topical application of the test item one week after intradermal injections) until challenge procedure
- Test groups: One test group of 20 animals, receiving Freund's Complete Adjuvant (FCA) emulsified 1:1 in sterile water (1st pair), 6% (w/w) of the test substance in archais oil (2nd pair) and 6% (w/w) of the test substance in a 1:1 mixture of FCA and archais oil (3rd pair).
- Control group: A control group of 10 animals was treated with FCA emulsified 1:1 in sterile water (1st pair), archais oil (2nd pair) and FCA emulsified 1:1 in sterile water (3rd pair)
- Site: An area of dorsal skin 4 x 6 cm in the scapular region
- Frequency of applications: Single simultaneous application of three pairs of intradermal injections, following a single topical induction after 6 days
- Duration: 6 days until 0.5 g sodium lauryl sulphate (10% in petrolatum) was massaged into the skin to provoke a mild inflammatory reaction. 24 hours later, 0.25 mL of ethanol/diethylphthlate 1:1(control group) or 50% test article in ethanol/diethylphthlate 1:1 was spread over a 2x4 cm patch and placed on the skin and covered with impermeable bandage. The dressing was left in place for 48 hours.
- Concentrations: 6% (w/w) test article in arachis oil

B. CHALLENGE EXPOSURE
- No. of exposures: 1
- Days of challenge: On day 20 (duration = 1 day)
- Exposure period: From day 20 to day 21
- Test groups: One test group of 20 animals, receiving a volume of 0.1 mL of the test item (25% test item in ethanol/diethylphthlate 1:1, left anterior flank) or control treatment (ethanol/diethylphthlate 1:1, left posterior flank)
- Control group: One control group of 10 animals, receiving a volume of 0.1 mL of the test item (25% test item in ethanol/diethylphthlate 1:1, left anterior flank). The left posterior flank was used for another substance.
- Site: Left anterior flank (test item) and left posterior flank (vehicle)
- Concentrations: 0.1 mL of 25% test item in ethanol/diethylphthlate 1:1
- Evaluation: 24 and 48 hours after challenge
Challenge controls:
The left posterior flank was treated with ethanol/diethylphthalate in the test group. The left posterior flank of the control group was used for another substance.
Positive control substance(s):
no

Results and discussion

Positive control results:
No positive control was included. The sensitivity and reliability of the experimental technique was assessed at regular intervals using formaldehyde (0.1% for intradermal induction and 5% for topical induction and challenge) dissolved in distilled water. The latest positive control study was performed from 10.10.1996 to 07.11.1996 in which 90% of the animals responded positively.

In vivo (non-LLNA)

Resultsopen allclose all
Key result
Reading:
2nd reading
Hours after challenge:
48
Group:
positive control
Dose level:
5% formaldehyde
No. with + reactions:
9
Total no. in group:
10
Clinical observations:
No clinical signs observed
Remarks on result:
positive indication of skin sensitisation
Key result
Reading:
1st reading
Hours after challenge:
24
Group:
positive control
Dose level:
5% formaldehyde
No. with + reactions:
9
Total no. in group:
10
Clinical observations:
No clinical signs observed
Remarks on result:
positive indication of skin sensitisation
Key result
Reading:
2nd reading
Hours after challenge:
48
Group:
negative control
Dose level:
25% (w/w) test article in ethanol/diethylphthlate
No. with + reactions:
0
Total no. in group:
10
Clinical observations:
No clinical signs observed
Remarks on result:
no indication of skin sensitisation
Key result
Reading:
1st reading
Hours after challenge:
24
Group:
negative control
Dose level:
25% (w/w) test article in ethanol/diethylphthlate
No. with + reactions:
0
Total no. in group:
10
Clinical observations:
No clinical signs observed
Remarks on result:
no indication of skin sensitisation
Key result
Reading:
2nd reading
Hours after challenge:
48
Group:
test chemical
Dose level:
25% (w/w) test article in ethanol/diethylphthlate
No. with + reactions:
0
Total no. in group:
20
Clinical observations:
No clinical signs observed
Remarks on result:
no indication of skin sensitisation
Key result
Reading:
1st reading
Hours after challenge:
24
Group:
test chemical
Dose level:
25% (w/w) test article in ethanol/diethylphthlate
No. with + reactions:
0
Total no. in group:
20
Clinical observations:
Slight or discrete erythema was observed in one animal at the left posterior flank (vehicle treatment with ethanol/diethylphthlate 1:1) after 24 hours.
Remarks on result:
no indication of skin sensitisation

Applicant's summary and conclusion

Conclusions:
In a Guinea Pig Maximization Test according to OECD guideline 406, no evidence of delayed contact hypersensitivity was seen after treatment with the test item under the experimental conditions.
Executive summary:

The dermal sensitizing potential of the test item was investigated according to one of the methods recommended in the OECD Guidelines No. 406, "Skin Sensitization", 1992 and the EEC Guideline "EEC 92/69 part 6B", 1992. The delayed contact hypersensitivity test used was the Guinea Pig Maximization Test described by B. Magnusson and A. M. Kligman. Thirty animals divided into a test group of 20 animals and a negative control group of 10 animals were included in the study. The study comprised an induction and a challenge phase. The animals in the test group were induced with the test article whereas the animals in the control group were induced with Arachis oil for intradermal induction and Ethanol/diethylphthlate 1:1 for dermal induction. The induction procedure included intradermal injections and a closed patch topical application one week apart. All animals were challenged by a closed patch topical application of the test article for 24 hours. The challenge procedure included a closed patch topical treatment of the test article an the flank 3 weeks after the intradermal injection. The skin reactions were evaluated 24 and 48 hours after the challenge application. A 6% (w/w) test article concentration in Arachis oil was used for the intradermal induction. A 50% (w/w) test article concentration in Ethanol/diethylphthlate 1:1 was used for the topical induction and a 25% (w/w) test article concentration in Ethanol/diethylphthlate 1:1 was used for the challenge application. Under these experimental conditions no evidence of delayed contact hypersensitivity was seen after treatment with the test item.