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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
Study period:
27 October 1997 - 27 November 1997
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: the study was conducted according to OCED Guideline 406 and EU method B.6 without deviations and based on GLP practices.
Qualifier:
according to
Guideline:
OECD Guideline 406 (Skin Sensitisation)
Deviations:
no
Qualifier:
according to
Guideline:
EU Method B.6 (Skin Sensitisation)
Deviations:
no
GLP compliance:
yes
Type of study:
guinea pig maximisation test
Species:
guinea pig
Strain:
Dunkin-Hartley
Sex:
female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Charles River, Germany
- Age at study initiation: 6 weeks old
- Weight at study initiation: < 500 grams
- Housing: Group housing of 5 animals per cage with wire-mesh floors
- Diet (e.g. ad libitum): Standard Guinea Pig Diet, including ascorbic acid (1600 mg/kg); LC-23-B, pellet diameter 4mm (Hope Farms, Woerden, The Neitherlands), ad libitum. Additionally, hay was provided once per week.
- Water (e.g. ad libitum): Tap-water, ad libitum
- Acclimation period: At least 5 days before the start of treatment under laboratory conditions

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 21 deg C
- Humidity (%): 50%
- Air changes (per hr): 15/hour
- Photoperiod (hrs dark / hrs light): 12/12

IN-LIFE DATES: From: Not documented in study report To: Not documented in study report
Route:
intradermal and epicutaneous
Vehicle:
corn oil
Concentration / amount:
Based on the results of the preliminary irritation study, the test concentrations selected for the Main Study were a 0.5% concentration for the intradermal induction and a 20% concentration for the epidermal induction exposure. A 5% test substance concentration was selected for the challenge phase.
Route:
epicutaneous, semiocclusive
Vehicle:
corn oil
Concentration / amount:
Based on the results of the preliminary irritation study, the test concentrations selected for the Main Study were a 0.5% concentration for the intradermal induction and a 20% concentration for the epidermal induction exposure. A 5% test substance concentration was selected for the challenge phase.
No. of animals per dose:
10 females in experimental group
5 females in control group
Details on study design:
RANGE FINDING TESTS: Prior to the start of the Main Study, the intradermal and epidermal irritancy of Epyrrol was investigated to select test substance concentrations suitable for the induction and challenge phase of the Main Study. The selection was based on the absence of toxicity and on the following criteria for each route and or study phase: INDUCTION (intradermal and epidermal): the highest possible concentration that produces moderate irritation (the intradermal reaction may include slight necrosis (<3 mm in diameter)). CHALLENGE: the maximum non-irritant concentration. Selection of this concentration depends on the number of factors and exact criteria did not always apply. The test system, procedures and techniques were identical to those used during the main study, unless otherwise specified. The animals were selected from stock and were between 5-9 weeks old, and as a consequence the body weights could exceed 500 grams, Body weights were determined prior to treatment.

INTRADERMAL INJECTIONS: A series of four test substance concentrations was used, the highest concentration being the maximum concentration that could technically be injected. Each of two animals received two different concentrations in duplicate (0.1 ml/site) in the clipped scapular region. The injection sites were assessed for irritation 24 and 48 hours after treatment.

EPIDERMAL APPLICATIONS: A series of four test substance concentrations was used; the highest on concentration being the maximum concentration that could technically be applied. Two different concentrations were applied (0.5 ml each) per animal to the clipped flank, using Metalline patches (2X3 cm) mounted on Medical tape, which were held in place with Micropore tape and subsequently Coban elastic bandage. The animals received intradermal injections were treated with the lowest concentrations and two further animals with the highest concentrations. After 24 hours, the dressing was removed and the skin cleaned of residual test substance. The treated skin areas were assessed for irritation 24 and 48 hours after exposure.

RESULTS:
Based on the results of the preliminary irritation study, the test concentrations selected for the Main Study were a 0.5% concentration for the intradermal induction and a 20% concentration for the epidermal induction exposure. A 5% test substance concentration was selected for the challenge phase.

MAIN STUDY
A. INDUCTION EXPOSURE
- No. of exposures: Two, Day 1 and Day 8
- Exposure period: 48 hours
- Test groups: Experimental animal groups
- Control group: The control animals were treated as described in the experimental animals, except exposed to vehicle only.
- Site: Flank
- Frequency of applications: Three intradermal injections (0.1 ml/site)
- Duration: 48 hours
- Concentrations: 0.5% on Day 1 and 20% on Day 8

B. CHALLENGE EXPOSURE
- No. of exposures: Single exposure
- Day(s) of challenge: Day 22
- Exposure period: 24 hours
- Test groups: All animals
- Control group: No data
- Site: Flank (One flank was clipped and treated by epidermal application, using Metalline patches (2X3cm) mounted on medical tape, which were held in place with Micropore tape and subsequently Coban elastic bandage.
- Concentrations: 5% test substance and the vehicle (0.5 ml each)
- Evaluation (hr after challenge): 24 hours after exposure, the skin was cleaned of residual test substance and vehicle. The treated sites were assessed for challenge reactions 24 and 48 hours after removal of the dressing.

OTHER: OBSERVATIONS:
Mortality/Viability: Twice daily
Toxicity: At least once daily
Body weights: Prior to start and at termination of the study
Irritation: skin reactions were graded according to a numerical scoring system. Furthermore, a description of all other (local) effects were recorded. Whenever necessary, the treated skin-areas were clipped at least 3 hours before the next skin reading to facilitate scoring.
Positive control substance(s):
no
Reading:
1st reading
Hours after challenge:
24
Group:
test group
Dose level:
5%
No. with + reactions:
10
Total no. in group:
10
Clinical observations:
Signs of necrosis and/or scaliness were seen in the treated skin sites of the majority of experimental animals.
Remarks on result:
other: see Remark
Remarks:
Reading: 1st reading. . Hours after challenge: 24.0. Group: test group. Dose level: 5%. No with. + reactions: 10.0. Total no. in groups: 10.0. Clinical observations: Signs of necrosis and/or scaliness were seen in the treated skin sites of the majority of experimental animals. .
Reading:
2nd reading
Hours after challenge:
48
Group:
test group
Dose level:
5%
No. with + reactions:
10
Total no. in group:
10
Clinical observations:
Signs of necrosis and/or scaliness were seen in the treated skin sites of the majority of experimental animals.
Remarks on result:
other: see Remark
Remarks:
Reading: 2nd reading. . Hours after challenge: 48.0. Group: test group. Dose level: 5%. No with. + reactions: 10.0. Total no. in groups: 10.0. Clinical observations: Signs of necrosis and/or scaliness were seen in the treated skin sites of the majority of experimental animals. .

Toxicity/Mortality:

No mortality occurred and no symptoms of systemic toxicity were observed in the animals of the main study.

Body Weights:

Body weights and body weight gain of experimental animals remained in the same range as controls over the study period.

Interpretation of results:
other: may cause sensitization by skin contact
Remarks:
Criteria used for interpretation of results: EU
Conclusions:
Taking into account the intensity and persistence of the responses and comparing these with the skin reactions seen in the control animals, it was considered that hypersensitivity to Epyrrol had been induced in the experimental animals. These results indicate a sensitization rate of 100%. Therefore Epyroll is classified as a skin sensitiser according DSD (R ) and CLP (H317)
Endpoint conclusion
Endpoint conclusion:
adverse effect observed (sensitising)
Additional information:
Migrated from Short description of key information:
GLP study according to OCED Guideline 406 and EU Method B.6 using guinea pigs, the test concentrations selected for the Main Study were a 0.5% concentration for the intradermal induction and a 20% concentration for the epidermal induction exposure. A 5% test substance concentration was selected for the challenge phase.

Justification for selection of skin sensitisation endpoint:
Taking into account the intensity and persistence of the responses and comparing these with the skin reactions seen in the control animals, it was considered that hypersensitivity to Epyrrol had been induced in the experimental animals. These results indicate a sensitization rate of 100%.

Respiratory sensitisation

Endpoint conclusion
Endpoint conclusion:
no study available
Additional information:
Migrated from Short description of key information:
Hypersensitivity to Epyrrol had been induced in the experimental animals, using OCED Guideline 406 and EU Method B.6

Justification for classification or non-classification