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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:
from 07-JUNE-2007 to 13-DEC-2007
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
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
Justification for non-LLNA method:
A maximization test according to OECD 406 guideline study is available.
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 : 350 +/- 21 g ; treated group: 340 +/- 14 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: 7-JUNE-2007 To: 13-JULY-2007
Route:
intradermal and epicutaneous
Vehicle:
other: 0.9% NaCl (intradermal injections), purified water (topical applications)
Concentration / amount:
Induction exposure: 10% (w/w) in 0.9% NaCl (intradermal), 50% (w/w) in purified water (epidermal)
Challenge exposure: 10% (w/w) in purified water
Route:
epicutaneous, occlusive
Vehicle:
other: 0.9% NaCl (intradermal injections), purified water (topical applications)
Concentration / amount:
Induction exposure: 10% (w/w) in 0.9% NaCl (intradermal), 50% (w/w) in purified water (epidermal)
Challenge exposure: 10% (w/w) in purified water
No. of animals per dose:
6 (intradermal and epidermal pre-test), 5 (control group), 10 (test group)
Details on study design:
RANGE FINDING TESTS: Based on the results of the pre-test at 5 and 10% (w/w), the test substance concentration of 10% (w/w) was selected for intradermal induction in the main study.
For epidermal applications, the test substance concentration of 50% (w/w) was chosen for the topical application of the induction phase (day 8). For the challenge application (day 22), the chosen concentration was 10% (w/w), the highest concentration which does not cause irritant effect.
The tables of the results of the pre-test were reported in the section: "Any other information on materials and methods incl. tables".

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 Complete Adjuvant) in 0.9% NaCl, or test item at 10% (w/w) in 0.9% NaCl, or test item at 10% (w/w) in the mixture FCA/0.9% NaCl (50/50, v/v)
> cutaneous application: test item at the concentration of 50% (w/w) in vehicle
- Control group:
> injections with 50% (v/v) FCA in 0.9% NaCl, or 0.9% NaCl alone, or vehicle at 50% (w/v) in a mixture FCA/0.9% NaCl (50/50, v/v)
> cutaneous application: vehicle alone
- Site: each side dorsal skin of the interscapular region (i.e. 3 pairs of sites)
- Frequency of applications: once
- Duration: 8 days (total duration of the induction period)
- Concentrations: 10% (w/w) in 0.9% NaCl (intradermal), 50% (w/w) in purified water (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 10% (w/w) in purified water and was then applied to a shaved area of the skin of the posterior right flank of all animals.
- Control group: 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: 10% (w/w) in purified water
- Evaluation: 24 and 48 hours after patch removal
Positive control substance(s):
yes
Remarks:
mercaptobenzothiazole (CAS No 149-30-4)
Positive control results:
Mercaptobenzothiazole was tested in the same conditions as described above. The positive control was not included in the study, but put in an other report as regularly controlled.
Under the experimental conditions of this study and according to the Magnusson and Kligman method, the reference item induced positive skin sensitization reactions in 78% guinea pigs and thus, the sensitivity of the guinea-pigs strain from the same source was considered satisfactory.
Reading:
1st reading
Hours after challenge:
24
Group:
test chemical
Dose level:
10% (w/w)
No. with + reactions:
2
Total no. in group:
10
Clinical observations:
Discrete erythema (grade 1) noted in 2 animals.
Remarks on result:
other: Reading: 1st reading. . Hours after challenge: 24.0. Group: test group. Dose level: 10% (w/w). No with. + reactions: 2.0. Total no. in groups: 10.0. Clinical observations: Discrete erythema (grade 1) noted in 2 animals..
Reading:
2nd reading
Hours after challenge:
48
Group:
test chemical
Dose level:
10% (w/w)
No. with + reactions:
0
Total no. in group:
10
Clinical observations:
None.
Remarks on result:
other: Reading: 2nd reading. . Hours after challenge: 48.0. Group: test group. Dose level: 10% (w/w). No with. + reactions: 0.0. Total no. in groups: 10.0. Clinical observations: None..
Reading:
1st reading
Hours after challenge:
24
Group:
negative control
No. with + reactions:
1
Total no. in group:
5
Clinical observations:
Discrete erythema (grade 1) noted in 1 animal.
Remarks on result:
other: Reading: 1st reading. . Hours after challenge: 24.0. Group: negative control. No with. + reactions: 1.0. Total no. in groups: 5.0. Clinical observations: Discrete erythema (grade 1) noted in 1 animal..
Reading:
2nd reading
Hours after challenge:
48
Group:
negative control
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. No with. + reactions: 0.0. Total no. in groups: 5.0. Clinical observations: None..

Marked local reactions (but no necrosis) at the intradermal injection sites were noted in a few animals of the control and treated groups, between day 13 and day 17. No systemic clinical signs and no deaths were observed during the study.

- Results of test

 Groups

sex

Animal number

24h

48h

LF

RF

LF

RF

Control

Female

171

0

1

0

0

 

172

0

0

0

0

 

173

0

0

0

0

 

174

0

0

0

0

 

175

0

0

0

0

Treated

Female

176

0

0

S

0

 

177

0

0

0

0

 

 

178

0

0

0

0

 

179

0

0

S

S

 

180

0

0

0

0

 

181

0

0

0

0

 

182

0

1

0

0

 

183

0

0

0

0

 

184

0

0

0

0

 

185

0

1

0

0

LF : left flank (vehicle)

RF: right flank (test item at the concentration of 10% (w/w))

S : dryness of the skin

After the challenge application of the test item, in the control group, a discrete erythema (grade 1) was observed on the right flank (receiving the test item) of 1/5 females, at the 24-hour reading. No cutaneous reactions persisted at the 48-hour reading. No cutaneous reactions were noted on the left flank (receiving the vehicle) of the animals.

In the treated group, a discrete erythema (grade 1) was noted on the right flank (receiving the test item) of 2/10 animals at the 24-hour reading. At the 48-hour reading, a dryness of the skin was observed on the left flank (receiving the vehicle) of 1/10 females and on both flanks of another female.

As the cutaneous reactions observed in the animals of the treated group were of similar incidence and severity when compared to those recorded in the animals of the control group, they were attributed to the irritant properties of the test item but not to delayed contact hypersensitivity.

 

Interpretation of results:
not sensitising
Remarks:
Migrated information
Conclusions:
Classification: not sensitizing
Executive summary:

The potential of the test item Reaction mass of lanthanum phosphate and cerium phosphate and terbium phosphate to induce delayed contact hypersensitivity was evaluated in guinea pigs according to the maximization method of Magnusson and Kligman and to OECD No. 406 and EC B.6 guidelines and in compliance with the principles of Good Laboratory Practice Regulations.

Fifteen guinea pigs were allocated to two groups: a control group of five females and a treated group of ten females.

 On day 1, three pairs of intradermal injections were performed in the interscapular region of all animals:

• Freund's complete adjuvant (FCA) diluted to 50% (v/v) with 0.9% NaCl (both groups),

• test item at the concentration of 10% (w/w) in 0.9% NaCl (treated group) or vehicle alone (control group),

• test item at the concentration of 10% (w/w) in a mixture FCA/0.9% NaCl (50/50, w/w) (treated group) or vehicle at the concentration of 50% (w/v) in a mixture FCA/0.9% NaCl (50/50, v/v) (control group).

On day 7, a topical application of sodium lauryl sulfate at 10% (w/w) in vaseline was performed to the same area of the animals of both groups, in order to induce a local irritation.

On day 8, the animals of the treated group received a topical application of the test item at the concentration of 50% (w/w) in purified water to the same test siteunder an occlusive dressing for 48 hours. The animals of the control group received an application of

the vehicle under the same experimental conditions.

On day 22, all animals of both groups were challenged by a cutaneous application of the test item at the concentration of 10% (w/w) in purified water to the right flank under an occlusive dressing for 24 hours. The vehicle was applied to the left flank under the same experimental conditions.

Skin reactions were evaluated approximately 24 and 48 hours after removal of the dressing.

No deaths and no systemic clinical signs were noted during the study.

After the challenge application of the test item, in the control group, a discrete erythema was observed on the right flank (receiving the test item) of 1/5 females, at the 24-hour reading. No cutaneous reactions persisted at the 48-hour reading. No cutaneous reactions were noted on the left flank (receiving the vehicle) of the animals.

In the treated group, a discrete erythema was noted on the right flank (receiving the test item) of 2/10 animals at the 24-hour reading. At the 48-hour reading, a dryness of the skin was observed on the left flank (receiving the vehicle) of 1/10 females and on both flanks of another female.

As the cutaneous reactions observed in the animals of the treated group were of similar incidence and severity when compared to those recorded in the animals of the control group, they were attributed to the irritant properties of the test item but not to delayed contact hypersensitivity.

Under the experimental conditions of this study and according to the maximization method of Magnusson and Kligman, the test item Reaction mass of lanthanum phosphate and cerium phosphate and terbium phosphate did not induce delayed contact hypersensitivity in guinea pigs and therefore should not be classified according to the EU criteria.

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

Endpoint conclusion
Endpoint conclusion:
no adverse effect observed (not sensitising)
Additional information:

A skin sensitization study is available on Reaction Mass of Lanthanum Phosphate and Cerium Phosphate and Terbium Phosphate. This study was performed according to OECD guideline n° 406 and EU Method B.6 and in accordance with GLP. This study was thus scored as validity 1 according to Klimisch criteria and then was selected as the Key study.

The potential of the test item Reaction mass of lanthanum phosphate and cerium phosphate and terbium phosphate to induce delayed contact hypersensitivity was evaluated in guinea pigs according to the maximization method of Magnusson and Kligman and to OECD No. 406 and EC B.6 guidelines and in compliance with the principles of Good Laboratory Practice Regulations (CIT, 2007).

Fifteen guinea pigs were allocated to two groups: a control group of five females and a treated group of ten females.

 On day 1, three pairs of intradermal injections were performed in the interscapular region of all animals:

• Freund's complete adjuvant (FCA) diluted to 50% (v/v) with 0.9% NaCl (both groups),

• test item at the concentration of 10% (w/w) in 0.9% NaCl (treated group) or vehicle alone (control group),

• test item at the concentration of 10% (w/w) in a mixture FCA/0.9% NaCl (50/50, w/w) (treated group) or vehicle at the concentration of 50% (w/v) in a mixture FCA/0.9% NaCl (50/50, v/v) (control group).

On day 7, a topical application of sodium lauryl sulfate at 10% (w/w) in vaseline was performed to the same area of the animals of both groups, in order to induce a local irritation.

On day 8, the animals of the treated group received a topical application of the test item at the concentration of 50% (w/w) in purified water to the same test site under an occlusive dressing for 48 hours. The animals of the control group received an application of the vehicle under the same experimental conditions.

On day 22, all animals of both groups were challenged by a cutaneous application of the test item at the concentration of 10% (w/w) in purified water to the right flank under an occlusive dressing for 24 hours. The vehicle alone was applied to the left flank under the same experimental conditions.

Skin reactions were evaluated approximately 24 and 48 hours after removal of the dressing.

No deaths and no systemic clinical signs were noted during the study.

After the challenge application of the test item, in the control group, a discrete erythema was observed on the right flank (receiving the test item) of 1/5 females, at the 24-hour reading. No cutaneous reactions persisted at the 48-hour reading. No cutaneous reactions were noted on the left flank (receiving the vehicle) of the animals.

In the treated group, a discrete erythema was noted on the right flank (receiving the test item) of 2/10 animals at the 24-hour reading. At the 48-hour reading, a dryness of the skin was observed on the left flank (receiving the vehicle) of 1/10 females and on both flanks of another female.

As the cutaneous reactions observed in the animals of the treated group were of similar incidence and severity when compared to those recorded in the animals of the control group, they were attributed to the irritant properties of the test item but not to delayed contact hypersensitivity.

Under the experimental conditions of this study and according to the maximization method of Magnusson and Kligman, the test item Reaction mass of lanthanum phosphate and cerium phosphate and terbium phosphate did not induce delayed contact hypersensitivity in guinea pigs and therefore should not be classified according to the EU criteria.


Migrated from Short description of key information:
No indication of skin sensitization potential in vivo in a Guinea-Pig Maximization Test.

Justification for selection of skin sensitisation endpoint:
Only one study is available.
Key study quoted as reliability 1 according to Klimisch criteria (performed according to OECD guidelines and in accordance with GLP)

Justification for classification or non-classification

Based on the classification criteria of Annex VI Directive 67/548/EEC or UN/EU GHS, and given the absence of positive reactions attributed to delayed contact hypersensitivity in a GPMT, Reaction mass of lanthanum phosphate and cerium phosphate and terbium phosphate is not classified as a skin sensitizer.

No data are available for respiratory sensitisation; therefore no conclusion can be made on the classification of this end-point.

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