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Toxicological information

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 2 November 2005 to 31 January 2006
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2006
Report Date:
2006

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
EU Method B.6 (Skin Sensitisation)
Version / remarks:
Cited as Directive 96/54/EC, B.6
Deviations:
no
GLP compliance:
yes (incl. certificate)
Type of study:
guinea pig maximisation test
Justification for non-LLNA method:
The GPMT method is the preferred test method because there is an increased risk for false positive results when performing the LLNA. Additionally, insoluble inorganic substances, such as yttrium oxide, are often not able to penetrate the skin.

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
solid: particulate/powder
Details on test material:
Name of test material: yttrium oxyde
Substance type: mono-constituent substance
Further information on test material confidential.

In vivo test system

Test animals

Species:
guinea pig
Strain:
Dunkin-Hartley
Sex:
female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Charles River Deutschland GmbH
- Age at study initiation: 4 - 6 weeks
- Weight at study initiation: 321 - 393 g
- Housing: individually in Makrolon type-4 cages with standard softwood bedding
- Diet: pelleted standard Provimi Kliba 3418, ad libitum
- Water: community tap water from Füllinsdorf, ad libitum
- Acclimation period: 12 days

ENVIRONMENTAL CONDITIONS
- Temperature: 22 +/- 3 °C
- Humidity: 30 - 70 %
- Air changes: 10 - 15 per hr
- Photoperiod: 12 hrs dark / 12 hrs light

IN-LIFE DATES: from 14-NOV-2005 to 08-DEC-2005

Study design: in vivo (non-LLNA)

Inductionopen allclose all
Route:
intradermal
Vehicle:
water
Concentration / amount:
25% w/w
Day(s)/duration:
day 1 of treatment
Route:
epicutaneous, occlusive
Vehicle:
water
Concentration / amount:
50% w/w
Day(s)/duration:
day 8 of treatment; 48 hours of exposure
Challenge
No.:
#1
Route:
epicutaneous, occlusive
Vehicle:
water
Concentration / amount:
50% w/w
Day(s)/duration:
day 22 of treatment; 24 hours of exposure
No. of animals per dose:
15 (main study: 5 in control group, 10 in test group), 3 (pre-test)
Details on study design:
RANGE FINDING TEST
INTRADERMAL INJECTIONS: One guinea pig was intradermally injected into the clipped flank at concentrations of 25% and 15% (w/w) of the test item in purified water. Due to the high viscosity of the application dilution and the obstacle caused by the tissues, it was not technically possible to inject the liquid dilution at the concentration of 50% (w/w) into the intracellular space. Dermal reactions were assessed approximately 24 hours later. Based on the results, the test item concentration of 25% (w/w) was selected for intradermal induction in the main study.
EPIDERMAL APPLICATIONS: 4 patches of filter paper were saturated with the test item at 50% (technically the highest possible concentration to be applied sufficiently), 25%, 15% and 10% (w/w) in purified water and applied to the clipped and shaved flanks of 2 guinea pigs. The patches were covered by a strip of aluminum foil and firmly secured by elastic plaster wrapped around the trunk and covered with impervious adhesive tape. The dressings were removed after an exposure period of 24 hours. 21 hours after removal of the dressing the application site was depilated in order to visualise any resulting erythema. 3 hours later (48 hours from the epidermal application) the skin reaction was observed and recorded. After this observation a second observation (approximately 72 hours from the epidermal application) was made and once again recorded. Based on the results obtained the concentration selected for induction and challenge in the main study was 50% (w/w).

MAIN STUDY
A. INDUCTION EXPOSURE
- No. of exposures: 2 (intradermal injections + topical application)
- Type of epicutaneous induction: occlusive
- SLS application: yes (0.5 mL at 10% w/w in paraffinum perliquidum)
- Exposure period: on D1 (intradermal) and D8 (epidermal, 48-hr exposure)
- Test groups:
*Intradermal induction:
1) 1:1 (v/v) mixture of Freund's Complete Adjuvant and physiological saline
2) The test item at 25% (w/w) in purified water
3) The test item at 25% (w/w) in a 1:1 (v/v) mixture of Freund's Complete Adjuvant and physiological saline
*Epidermal application: test item at 50% (w/w) in purified water
- Control group:
*Intradermal induction:
1) 1:1 (v/v) mixture of Freund's Complete Adjuvant and physiological saline
2) Purified water
3) 1:1 (w/w) mixture of purified water in a 1:1 (v/v) mixture of Freund's Complete Adjuvant and physiological saline
*Epidermal application: purified water only
- Site: dorsal skin of the scapular region
- Frequency of applications: not applicable
- Duration: 8 days (total duration of induction period)
- Concentrations: 25% (w/w) by intradermal injection, 50% (w/w) by epidermal application

B. CHALLENGE EXPOSURE
- No. of exposures: 1 (epidermal application)
- Day of challenge: day 22
- Exposure period: 24 hours
- Test groups: test item in the vehicle only (+ vehicle only on the other flank)
- Control group: test item in the vehicle only (+ vehicle only on the other flank)
- Site: left (test item) and right (vehicle) flanks
- Concentrations: 50% (w/w)
- Evaluation: 48 and 72 hr after beginning of the challenge

- Statistics: Descriptive statistics were calculated for body weights. No inferential statistics were used.
Challenge controls:
50% (w/w) of test item in purified water was applied to the left side of the animals. The right shaved side of all animals was treated with purified water.
Positive control substance(s):
yes
Remarks:
hexyl cinnamic aldehyde (CAS No 101-86-0) (regularly controlled)

Results and discussion

Positive control results:
Hexyl cinnamic aldehyde was tested in the same conditions as described above. Based on the findings, hexyl cinnamic aldehyde at 1% in PEG 300 was considered as a skin sensitiser. The positive control was not included in the study, but put in an other report as regular control.

In vivo (non-LLNA)

Resultsopen allclose all
Key result
Reading:
1st reading
Hours after challenge:
48
Group:
test group
Dose level:
50% yttrium oxide (w/w) in purified water
No. with + reactions:
0
Total no. in group:
10
Clinical observations:
none
Remarks on result:
no indication of skin sensitisation
Key result
Reading:
2nd reading
Hours after challenge:
72
Group:
test group
Dose level:
50% yttrium oxide (w/w) in purified water
No. with + reactions:
0
Total no. in group:
10
Clinical observations:
none
Remarks on result:
no indication of skin sensitisation
Key result
Reading:
1st reading
Hours after challenge:
48
Group:
negative control
Dose level:
50% yttrium oxide (w/w) in purified water
No. with + reactions:
0
Total no. in group:
5
Clinical observations:
none
Remarks on result:
no indication of skin sensitisation
Key result
Reading:
2nd reading
Hours after challenge:
72
Group:
negative control
Dose level:
50% yttrium oxide (w/w) in purified water
No. with + reactions:
0
Total no. in group:
5
Clinical observations:
none
Remarks on result:
no indication of skin sensitisation
Reading:
1st reading
Hours after challenge:
48
Group:
other: positive control (first challenge)
Dose level:
1% (w/w) alpha-hexylcinnamaldehyde in PEG 300
No. with + reactions:
4
Total no. in group:
10
Clinical observations:
no data
Remarks on result:
positive indication of skin sensitisation
Reading:
1st reading
Hours after challenge:
48
Group:
other: positive control (first challenge)
Dose level:
0.1% (w/w) alpha-hexylcinnamaldehyde in PEG 300
No. with + reactions:
0
Total no. in group:
10
Clinical observations:
no data
Remarks on result:
no indication of skin sensitisation
Reading:
2nd reading
Hours after challenge:
72
Group:
other: positive control (first challenge)
Dose level:
1% (w/w) alpha-hexylcinnamaldehyde in PEG 300
No. with + reactions:
1
Total no. in group:
10
Clinical observations:
no data
Remarks on result:
no indication of skin sensitisation
Reading:
2nd reading
Hours after challenge:
72
Group:
other: positive control (second challenge)
Dose level:
0.1% (w/w) alpha-hexylcinnamaldehyde in PEG 300
No. with + reactions:
0
Total no. in group:
10
Clinical observations:
no data
Remarks on result:
no indication of skin sensitisation
Key result
Reading:
rechallenge
Hours after challenge:
48
Group:
other: positive control (second challenge)
Dose level:
1% (w/w) alpha-hexylcinnamaldehyde in PEG 300
No. with + reactions:
7
Total no. in group:
10
Clinical observations:
no data
Remarks on result:
positive indication of skin sensitisation
Key result
Reading:
rechallenge
Hours after challenge:
48
Group:
other: positive control (second challenge)
Dose level:
0.1% (w/w) alpha-hexylcinnamaldehyde in PEG 300
No. with + reactions:
1
Total no. in group:
10
Clinical observations:
no data
Remarks on result:
no indication of skin sensitisation
Key result
Reading:
rechallenge
Hours after challenge:
72
Group:
other: positive control (second challenge)
Dose level:
1% (w/w) alpha-hexylcinnamaldehyde in PEG 300
No. with + reactions:
4
Total no. in group:
10
Clinical observations:
no data
Remarks on result:
positive indication of skin sensitisation
Key result
Reading:
rechallenge
Hours after challenge:
72
Group:
other: positive control (second challenge)
Dose level:
0.1% (w/w) alpha-hexylcinnamaldehyde in PEG 300
No. with + reactions:
1
Total no. in group:
10
Clinical observations:
no data
Remarks on result:
no indication of skin sensitisation

Any other information on results incl. tables

No mortality, no sign of systemic toxicity and no effect on body weight was observed during the study.

Detailed results on animals are shown in the following tables:

Table 1: Control group – skin response after the challenge application of purified water (right flank)

Animal
No.

Sex

REACTION
AFTER REMOVAL OF BANDAGE

24 hours

48 hours

262

female

0

0

263

female

0

0

264

female

0

0

265

female

0

0

266

female

0

0

 

Table 2: Control group – skin response after challenge application of yttrium oxyde, 50% (w/w) in purified water (left flank)

Animal
No.

Sex

REACTION
AFTER REMOVAL OF BANDAGE

24 hours

48 hours

262

female

0

0

263

female

0

0

264

female

0

0

265

female

0

0

266

female

0

0

Approximately 3 hours prior to the 24-hour reading of the challenge the test sites were depilated.

  

Table 3: Test group – skin response after the challenge application of purified water (right flank)

Animal
No.

Sex

REACTION
AFTER REMOVAL OF BANDAGE

24 hours

48 hours

267

female

0

0

268

female

0

0

269

female

0

0

270

female

0

0

271

female

0

0

272

female

0

0

273

female

0

0

274

female

0

0

275

female

0

0

276

female

0

0

  

Table 4: Test group – skin response after challenge application of yttrium oxyde, 50% (w/w) in purified water (left flank)

Animal
No.

Sex

REACTION
AFTER REMOVAL OF BANDAGE

24 hours

48 hours

267

female

0

0

268

female

0

0

269

female

0

0

270

female

0

0

271

female

0

0

272

female

0

0

273

female

0

0

274

female

0

0

275

female

0

0

276

female

0

0

 

Approximately 3 hours prior to the 24-hour reading of the challenge the test sites were depilated.

Applicant's summary and conclusion

Interpretation of results:
GHS criteria not met
Conclusions:
The sensitisation potential of yttrium oxide was evaluated on Dunkin-Hartley guinea pigs according to the maximisation method of Magnusson and Kligman, described in Directive 67/548/EEC, method B.6, and in compliance with Good Laboratory Practice. Ten test and five control guinea pigs were included in this study. Induction was carried out as following:
- On day one, animals were injected by the intracutaneous route with yttrium oxide (25% w/w in purified water) +/- Freund's Complete Adjuvant (treated group) or with purified water +/- Freund's Complete Adjuvant (control group) or with Freund's Complete Adjuvant alone (both groups).
- On day 7, the same region received a topical application of sodium lauryl sulfate (10% w/w in paraffinum perliquidum) in order to induce local irritation.
- On day 8, a 48-hour topical occlusive application was performed with yttrium oxide at 50% w/w in purified water (test animals) or the vehicle (controls).
- On day 22, the control and test animals were challenged by a cutaneous application of the test substance at 50% w/w in purified water to the left flank. The right flank served as control and received the vehicle only. The test substance and the vehicle were maintained under an occlusive dressing for 24 hours.
Skin reactions (erythema and oedema) were evaluated approximately 24 and 48 hours after removal of the dressing. No clinical signs and no deaths related to treatment were noted during the study. After the challenge application, at the 24-hour and 48-hour readings, no cutaneous reactions were noted. Based on the results of this study, yttrium oxide is not a dermal sensitiser.