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Skin sensitisation

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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:
from 24-MAY-2007 to 30-NOVEMBER-2007
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: The study was performed according to EU / OECD guidelines and GLP

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2007
Report date:
2007

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to guideline
Guideline:
OECD Guideline 406 (Skin Sensitisation)
Deviations:
no
Qualifier:
according to guideline
Guideline:
EU Method B.6 (Skin Sensitisation)
Deviations:
no
GLP compliance:
yes
Type of study:
guinea pig maximisation test

Test material

Constituent 1
Chemical structure
Reference substance name:
Reference substance 001
EC Number:
909-701-4
Molecular formula:
(Ce (1-x)Lax)OyFz

In vivo test system

Test animals

Species:
guinea pig
Strain:
Hartley
Sex:
female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Charles River Laboratories France, l’Arbresle, France
- Age at study initiation: 1 - 2 months
- Weight at study initiation: control group : 354 +/- 20 g ; treated group: 358 +/- 16 g
- Housing: housed individually in polycarbonate cages with stainless steel lid (48 cm x 27 cm x 20 cm) equipped with a polypropylene bottle. Each cage contained autoclaved sawdust (SICSA, Alfortville, France). Sawdust is analyzed by the supplier for composition and contaminant levels.
- Diet: 106 pelleted diet (SAFE, Villemoisson, Epinay-sur-Orge, France), ad libitum. Food is analyzed regularly by the supplier for composition and contaminant levels.
- Water : Drinking water filtered by a FG Millipore membrane (0.22 micron) was provided ad libitum.
- Acclimation period : at least 5 days before the beginning of the study.

ENVIRONMENTAL CONDITIONS
- Temperature: 22 +/- 2 °C
- Humidity: 30 to 70%
- Air changes: ventilation: approximately 12 cycles/hour of filtered, non-recycled air.
- Photoperiod: light/dark cycle: 12 h/12 h

IN-LIFE DATES: From: 24-MAY-2007 To: 29-JUNE-2007

Study design: in vivo (non-LLNA)

Inductionopen allclose all
Route:
intradermal and epicutaneous
Vehicle:
other: corn oil (intradermal injections), olive oil (topical applications)
Concentration / amount:
Induction exposure: 25% (intradermal), 25% (epidermal)
Challenge exposure: 25% (w/w) in vehicle (olive oil)
Challengeopen allclose all
Route:
epicutaneous, occlusive
Vehicle:
other: corn oil (intradermal injections), olive oil (topical applications)
Concentration / amount:
Induction exposure: 25% (intradermal), 25% (epidermal)
Challenge exposure: 25% (w/w) in vehicle (olive oil)
No. of animals per dose:
4 (intradermal and epidermal pre-test), 5 (control group), 10 (test group)
Details on study design:
RANGE FINDING TESTS:
Choice of the vehicle:
The test item was not soluble in 0.9% NaCl, purified water, ethanol/water (80/20, p/p) and acetone: two phases were observed.
The vehicle chosen for intradermal injections was corn oil: a homogeneous dosage form preparation was obtained at the maximum concentration of 25% (w/w). The dosage form preparation at the concentration of 25% (w/w) passed freely through a needle and into the dermis.
For topical applications, the vehicle used was olive oil for both induction phase and challenge application: a homogeneous dosage form preparation was obtained at the maximum concentration of 25% (w/w). A heterogeneous suspension was obtained at 50%.

Preliminary study:
A preliminary test was conducted in order to determine the concentrations to be tested in the main study.
By intradermal route (tested concentrations: 5%, 10% and 25% (w/w)):
Intradermal injections of the dosage form preparations (0.1 mL) were performed in the interscapular region, local reactions were evaluated approximately 24, 48 hours and 6 days after the injections.
In order to respect the criteria for the selection of concentrations (the concentration should be well-tolerated systemically and locally, intradermal injections should cause moderate irritant effect but no necrosis or ulceration of the skin), the concentration chosen for the main study was
25% (w/w).
By cutaneous route:
Under the conditions of the induction phase (tested concentrations: 10% and 25% (w/w)): a filter paper (approximately 8 cm2) was fully-loaded with a dosage form preparation and was then applied to the clipped area of the skin. The filter paper was held in place by means of an occlusive dressing for 48 hours, cutaneous reactions were evaluated 24 and 48 hours after removal of the dressing.
Under the conditions of the challenge phase (tested concentrations: 10% and 25% (w/w)): the filter paper of a chamber (Finn Chamber®) was fully-loaded with a dosage form preparation. The chamber was then applied to the clipped area of the skin (one concentration per flank). The chamber was held in place by means of an occlusive dressing for 24 hours, cutaneous reactions were evaluated 24 and 48 hours after removal of the dressings.
In order to respect the criteria for the selection of concentrations (the concentrations should be well-tolerated systemically and locally, cutaneous application for the induction should cause at most weak or moderate skin reactions or be the maximal practicable concentration, cutaneous application for the challenge phase should be the highest concentration which does not cause irritant effect), the concentration chosen for the topical applicationof the induction phase (day 8) and for the challenge application (day 22) was 25% (w/w).

MAIN STUDY
A. INDUCTION EXPOSURE
- No. of exposures: 2 (one intradermal and one cutaneous)
- type of epicutaneous induction: occlusive
- SLS application: Yes, 0.5 ml SLS at 10% (w/w) in vaseline
- Exposure period: 48 hours (cutaneous induction)
- Test groups:
> injections with 50% (v/v) FCA (Freund complexe adjuvant) in 0.9% NaCl, or test item at 25% (w/w) in corn oil, or test item at 25% (w/w) in the mixture FCA/0.9% NaCl (50/50, w/w)
> cutaneous application: test item at the concentration of 25% (w/w)in vehicle
- Control group:
> injections with 50% (v/v) FCA in 0.9% NaCl, or vehicle (corn oil), or vehicle at 50% (w/v) in a mixture FCA/0.9% NaCl (50/50, v/v)
> cutaneous application: vehicle alone
- Site: the interscapular region of the animals
- Frequency of applications: not applicable
- Duration: 8 days (total duration of induction period)
- Concentrations: 25% w/w in corn oil (intradermal), 25% w/w in olive oil (epidermal)

B. CHALLENGE EXPOSURE
- No. of exposures: 1
- Day(s) of challenge: day 22
- Exposure period: 24 hours
- Test groups: The filter paper of a chamber (Finn Chamber®) was fully-loaded with the test item at the concentration of 25% (w/w) in vehicle and was then applied to a shaved area of the skin of the posterior right flank of all animals. The vehicle was applied under the same experimental conditions to the skin of the posterior left flank.
- Control group: The filter paper of a chamber (Finn Chamber®) was fully-loaded with the test item at the concentration of 25% (w/w) in vehicle and was then applied to a shaved area of the skin of the posterior right flank of all animals. The vehicle was applied under the same experimental conditions to the skin of the posterior left flank.
- Site: right flank (test substance), left flank (control).
- Concentrations: 25% (w/w) in vehicle (olive oil) (right flank), vehicle alone (left flank)
- Evaluation: 24 and 48 hours after patch removal


Positive control substance(s):
yes
Remarks:
mercaptobenzothiazole (CAS No 149-30-4)

Results and discussion

Positive control results:
Mercaptobenzothiazole was not included in the study but is regularly tested by the laboratory under the same conditions.
Based on the findings, the sensitivity of the guinea-pigs strain from the same source is considered satisfactory.

In vivo (non-LLNA)

Resultsopen allclose all
Reading:
1st reading
Hours after challenge:
24
Group:
test chemical
Dose level:
25% (w/w) in oilive oil
No. with + reactions:
0
Total no. in group:
10
Clinical observations:
none
Remarks on result:
other: Reading: 1st reading. . Hours after challenge: 24.0. Group: test group. Dose level: 25% (w/w) in oilive oil. No with. + reactions: 0.0. Total no. in groups: 10.0. Clinical observations: none.
Reading:
2nd reading
Hours after challenge:
48
Group:
test chemical
Dose level:
25% (w/w) in olive oil
No. with + reactions:
0
Total no. in group:
10
Clinical observations:
Marked local reactions (but no necrosis) at the intradermal injection sites were noted in animals of treated group 2 No.133 and 135 on day 12 and No. 128 and 135 on day 20. No systemic clinical signs and no deaths were observed during the study.
Remarks on result:
other: see Remark
Remarks:
Reading: 2nd reading. . Hours after challenge: 48.0. Group: test group. Dose level: 25% (w/w) in olive oil. No with. + reactions: 0.0. Total no. in groups: 10.0. Clinical observations: Marked local reactions (but no necrosis) at the intradermal injection sites were noted in animals of treated group 2 No.133 and 135 on day 12 and No. 128 and 135 on day 20. No systemic clinical signs and no deaths were observed during the study. .
Reading:
1st reading
Hours after challenge:
24
Group:
negative control
Dose level:
25% w/w in olive oil
No. with + reactions:
0
Total no. in group:
5
Clinical observations:
none
Remarks on result:
other: Reading: 1st reading. . Hours after challenge: 24.0. Group: negative control. Dose level: 25% w/w in olive oil. No with. + reactions: 0.0. Total no. in groups: 5.0. Clinical observations: none.
Reading:
2nd reading
Hours after challenge:
48
Group:
negative control
Dose level:
25 % w/w in olive oil
No. with + reactions:
0
Total no. in group:
5
Clinical observations:
none
Remarks on result:
other: Reading: 2nd reading. . Hours after challenge: 48.0. Group: negative control. Dose level: 25 % w/w in olive oil. No with. + reactions: 0.0. Total no. in groups: 5.0. Clinical observations: none.

Applicant's summary and conclusion

Interpretation of results:
not sensitising
Remarks:
Migrated information
Conclusions:
The reaction mass of Cerium dioxide and Lanthanum oxide and Lanthanum fluoride is not classified as skin sensitizer according to Annex VI of the Directive 67/548/CEE and according to EU Regulation 1272/2008 (CLP).
Executive summary:

The reaction mass of Cerium dioxide and Lanthanum oxide and Lanthanum fluoride has been tested for skin sensitization on guinea pigs according to OECD guideline n° 406 and EC method B.6 and in compliance with Good Laboratory Practice.

Fifteen Hartley Crl: (HA) BR adult female guinea-pigs, (10 females for treated group and 5 females for control group) were used for the main test.

An induction treatment was carried out as follow:

Day 1, 3 pairs of intradermal injections were performed in the interscapular region of all animals:

- Freund’s Complete Adjuvent (FCA) diluted to 50 % (v/v) with 0.9% NaCl (both groups),

- Test substance at the concentration of 25% (w/w) in corn oil (treated group) or vehicle alone (control group),

- Test substance at the concentration of 25% (w/w) in corn oil in a mixture of FCA/0.9 % NaCl (50/50, w/w) (treated group) or vehicle at the concentration of 50 % (w/v) in a mixture of FCA/0.9% NaCl (50/50, v/v) (control group).

Day 7, the same skin site of both groups was pre-treated with sodium lauryl sulphate before to receive one day later a 48 hours occlusive topical application of the test article at the concentration of 25 % (w/w) in olive oil for treated group or olive oil alone for the control group.

The animals of both groups were challenged on day 22 with a 24 hours cutaneous occlusive application of the test article at the concentration of 25 % (w/w) in olive oil to the right flank and olive oil alone to the left flank.

The cutaneous reactions were graded for erythema and oedema 24 and 48 hours after removal of the dressing.

 

No deaths and no systemic clinical signs were noted during the study. The body weight change of the treated animals was similar to that of the controls. No cutaneous reactions were observed after the challenge application (score = 0) in both treated and control groups, both flanks at 24 and 48 hour after dressing removal.

 

From the results obtained, the reaction mass of Cerium dioxide and Lanthanum oxide and Lanthanum fluoride is not classified as skin sensitizer according to Annex VI of the Directive 67/548/CEE and according to EU Regulation 1272/2008 (CLP).

This skin sensitisation study is classified as acceptable. It does satisfy the guideline requirement for a skin sensitisation study (EC Method B.6) in the guinea pigs.