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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:
May - Sep 1979
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
comparable to guideline study with acceptable restrictions

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1980
Report date:
1980

Materials and methods

Test guideline
Qualifier:
equivalent or similar to guideline
Guideline:
OECD Guideline 406 (Skin Sensitisation)
Version / remarks:
adopted in 1992
Deviations:
yes
Remarks:
no reliability check, concentration for induction was not irritating
GLP compliance:
no
Type of study:
guinea pig maximisation test
Justification for non-LLNA method:
The study was conducted prior to the current requirement in Regulation (EC) 1907/2006 to perform an LLNA study (OECD 429) as the preferred in vivo skin sensitisation study.

Test material

Constituent 1
Chemical structure
Reference substance name:
Chlorocresol
EC Number:
200-431-6
EC Name:
Chlorocresol
Cas Number:
59-50-7
Molecular formula:
C7H7ClO
IUPAC Name:
4-chloro-3-methylphenol

In vivo test system

Test animals

Species:
guinea pig
Strain:
other: Pirbright White
Sex:
male/female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Lippische Versuchstierzucht, Extertal, Germany
- Weight at study initiation: 400 g (males; first study), 300 g (females; second study)
- Housing: in Type IV Makrolon cages with dust-free wood granulate
- Diet: Altromin standard diet for guinea pigs (Altromin GmbH, Lage, Germany), twice a week
- Water: tap water, ad libitum

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22 ± 1
- Photoperiod (hrs dark / hrs light): 12 / 12

Study design: in vivo (non-LLNA)

Inductionopen allclose all
Route:
intradermal
Vehicle:
other: Lutrol 300/ethanol 3:1
Concentration / amount:
25% (0.1 mL/site; first study)
1% (0.1 mL/site; second study)
Day(s)/duration:
single injection
Adequacy of induction:
not specified
Route:
epicutaneous, occlusive
Vehicle:
other: Lutrol 300/ethanol 3:1
Concentration / amount:
25% (first study)
1% (second study)
Day(s)/duration:
48 h
Adequacy of induction:
not specified
Challenge
No.:
#1
Route:
epicutaneous, occlusive
Vehicle:
other: Lutrol 300/ethanol 3:1
Concentration / amount:
12.5% and 25% (first study)
25% and 50% (second study)
Day(s)/duration:
24 h
Adequacy of challenge:
other: Concentrations of 25% (1st study) and 50% (2nd study) were found to be the maximum non-irritant concentrations in an orienting test for challenge.
No. of animals per dose:
15
Details on study design:
RANGE FINDING TESTS:
The maximum non-irritant concentration for challenge exposure was determined in orienting tests on groups of 4 untreated guinea pigs before triggering sensitization. In these tests, the substance was applied in the vehicle to various sites on the shaved flanks of each animal and left for 24 h under an occlusive dressing. The substance was applied at concentrations of 100%, 50%, 25%, and 12.5%. The 25% (fist study) and 50% (second study) suspensions were found to be the maximum non-irritant concentrations at evaluations carried out after a further 24 h and 48 h.

MAIN STUDY
A. INDUCTION EXPOSURE
- No. of exposures: 2 (intradermal and epicutaneous, respectively)
- Exposure period: single injection (intradermal) and 48 h (epicutaneous)
- Test groups:
Injection 1: Freund's complete adjuvant at 50% in water (first and second study)
Injection 2: 25% test item (first study) or 1% test item (second study) in the vehicle (Lutrol 300/ethanol 3:1)
Injection 3: 25% test item (first study) or 1% test item (second study) formulated in Freund's complete adjuvant
Epicutaneous: 25% test item (first study) or 1% test item (second study) in the vehicle (Lutrol 300/ethanol 3:1)
- Control group:
Injection 1: Freund's complete adjuvant at 50% in water (first and second study)
Injection 2: vehicle (Lutrol 300/ethanol 3:1)
Injection 3: 25% vehicle (Lutrol 300/ethanol 3:1; first study) or 1% vehicle (Lutrol 300/ethanol 3:1; second study) formulated in Freund's complete adjuvant
Epicutaneous: vehicle (Lutrol 300/ethanol 3:1)
- Site: flank on a shaven area of the back
- Frequency of applications: single injection (intradermal), single application (epicutaneous induction; one week after intradermal application)
- Duration: 9 days
- Concentrations: intradermal induction 25% (first study) or 1% (second study), epicutaneous 25% (first study) or 1% (second study)

B. CHALLENGE EXPOSURE
- No. of exposures: 1
- Day(s) of challenge: two weeks after topical induction
- Exposure period: 24 h
- Test groups: 12.5% and 25% test item (first study) or 25% and 50% test item (second study) in vehicle (Lutrol 300/ethanol 3:1)
- Control group: 12.5% and 25% test item (first study) or 25% and 50% test item (second study) in vehicle (Lutrol 300/ethanol 3:1)
- Site: left and right flanks
- Concentrations: 12.5% and 25% (first study) or 25% and 50% (second study)
- Evaluation (hr after challenge): 24 and 48 h after dressing removal
Challenge controls:
The control group is actually a challenge control.
Positive control substance(s):
no

Results and discussion

In vivo (non-LLNA)

Resultsopen allclose all
Reading:
1st reading
Hours after challenge:
24
Group:
negative control
Dose level:
Induction: 0%, challenge: 12.5% and 25%
No. with + reactions:
0
Total no. in group:
15
Clinical observations:
not specified
Remarks on result:
no indication of skin sensitisation
Remarks:
first study
Reading:
1st reading
Hours after challenge:
24
Group:
negative control
Dose level:
Induction: 0%, challenge: 25% and 50%
No. with + reactions:
0
Total no. in group:
15
Clinical observations:
not specified
Remarks on result:
no indication of skin sensitisation
Remarks:
second study
Reading:
1st reading
Hours after challenge:
24
Group:
test chemical
Dose level:
Induction: 25%, challenge: 12.5%
No. with + reactions:
1
Total no. in group:
15
Clinical observations:
not specified
Remarks on result:
no indication of skin sensitisation
Reading:
1st reading
Hours after challenge:
24
Group:
test chemical
Dose level:
Induction: 25%, challenge: 25%
No. with + reactions:
7
Total no. in group:
15
Clinical observations:
not specified
Remarks on result:
positive indication of skin sensitisation
Reading:
1st reading
Hours after challenge:
24
Group:
test chemical
Dose level:
Induction: 1%, challenge: 25%
No. with + reactions:
0
Total no. in group:
15
Clinical observations:
not specified
Remarks on result:
no indication of skin sensitisation
Reading:
1st reading
Hours after challenge:
24
Group:
test chemical
Dose level:
Induction: 1%, challenge: 50%
No. with + reactions:
4
Total no. in group:
15
Clinical observations:
not specified
Remarks on result:
positive indication of skin sensitisation
Reading:
2nd reading
Hours after challenge:
48
Group:
negative control
Dose level:
Induction: 0%, challenge: 12.5%
No. with + reactions:
0
Total no. in group:
15
Clinical observations:
not specified
Remarks on result:
no indication of skin sensitisation
Remarks:
first study
Reading:
2nd reading
Hours after challenge:
48
Group:
negative control
Dose level:
Induction: 0%, challenge: 25%
No. with + reactions:
1
Total no. in group:
15
Clinical observations:
not specified
Remarks on result:
no indication of skin sensitisation
Remarks:
first study
Reading:
2nd reading
Hours after challenge:
48
Group:
negative control
Dose level:
Induction: 0%, challenge: 25% and 50%
No. with + reactions:
0
Total no. in group:
15
Clinical observations:
not specified
Remarks on result:
no indication of skin sensitisation
Remarks:
second study
Reading:
2nd reading
Hours after challenge:
48
Group:
test chemical
Dose level:
Induction: 25%, challenge: 12.5%
No. with + reactions:
3
Total no. in group:
15
Clinical observations:
not specified
Remarks on result:
positive indication of skin sensitisation
Reading:
2nd reading
Hours after challenge:
48
Group:
test chemical
Dose level:
Induction: 25%, challenge: 25%
No. with + reactions:
13
Total no. in group:
15
Clinical observations:
not specified
Remarks on result:
positive indication of skin sensitisation
Reading:
2nd reading
Hours after challenge:
48
Group:
test chemical
Dose level:
Induction: 1%, challenge: 25%
No. with + reactions:
0
Total no. in group:
15
Clinical observations:
not specified
Remarks on result:
no indication of skin sensitisation
Reading:
2nd reading
Hours after challenge:
48
Group:
test chemical
Dose level:
Induction: 1%, challenge: 50%
No. with + reactions:
2
Total no. in group:
15
Clinical observations:
not specified
Remarks on result:
positive indication of skin sensitisation
Group:
positive control
Remarks on result:
not measured/tested

Applicant's summary and conclusion

Interpretation of results:
Category 1B (indication of skin sensitising potential) based on GHS criteria
Conclusions:
CLP: Skin Sens. 1B, H317
Executive summary:

A study for skin sensitisation in guinea pigs was conducted with the test substance using the Magnusson-Kligman method similar to the OECD Guideline 406 (1992). Groups of 15 Pirbright White guinea pigs each were used in two parts of the study. In the first study, male animals received intradermal induction treatments consisting of three pairs of injections. The first pair of injections was of Freund's complete adjuvant (FCA) 50% diluted in water, the second pair was of 25% of the test substance in the vehicle, and the third pair of injections was of 25% of the test substance with FCA. The control group received three pairs of injections that were the same as the test group except for the absence of the test material. One week following intradermal induction an epicutaneous induction under occlusive conditions for 48 h was performed. In the test group, 25% of the test substance in vehicle was applied, while for the control group only vehicle was applied. Three weeks after the intradermal induction the animals were challenged with 25% (right flank) or 12.5% (left flank) of the test substance in vehicle under occlusive conditions for 24 h. In the second study, female animals received were induced and challenged in the same way compared to the male animals of the first study with different test substance concentrations: For the intradermal and the topical induction 1% of the test substance was applied while 25% (left flank) and 50% (right flank) were used for topical challenge. Skin reactions were evaluated at 24 and 48 h after patch removal. The Magnusson-Kligman scoring system was used to rate the skin reactions. In the first study (25% induction concentration) a skin reaction was observed in 1/15 animals (6%) after challenging with 12.5% of the test substance at 24 h and in 3/15 animals (20%) at 48 h. The application of a challenging concentration of 25% led to sensitizing effects in 7/15 males (47%) at 24 and in 13/15 animals (87%) at 48 h. In the second study (1% induction concentration) no reactions were observed after challenging with 25% the test substance at 24 and 48 h while skin reactions were noted after topical challenge with 50% test substance (4/15 females at 24 h and 2/15 females at 48 h; 27 and 13%, respectively). Thus, under the conditions of this study, the test substance is classified as Skin Sensitizer Category 1B according to Regulation (EC) No 1272/2008.