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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
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Study conducted in compliance with Good laboratory Practice and internationally accepted guidelines.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2005

Materials and methods

Test guidelineopen allclose all
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
Justification for non-LLNA method:
The available study was conducted prior to the date on whch the LLNA became the method of choice.

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Name of test material (as cited in study report): Copper hydroxide.
- Composition of test material, percentage of components: 61.7% as copper.
- Lot/batch No.: 23063.

In vivo test system

Test animals

Species:
guinea pig
Strain:
Dunkin-Hartley
Sex:
male
Details on test animals and environmental conditions:
Adult male albino Dunkin-Hartley guinea pigs, 27 days old and with a weight range of 273 to 317 grams at initiation, were used for the main test.

Study design: in vivo (non-LLNA)

Inductionopen allclose all
Route:
intradermal and epicutaneous
Vehicle:
other: water for injection
Concentration / amount:
Refer to details on study design.
Challengeopen allclose all
Route:
epicutaneous, occlusive
Vehicle:
other: water for injection
Concentration / amount:
Refer to details on study design.
No. of animals per dose:
Fifteen (10 test animals, 5 control animals).
Details on study design:
RANGE FINDING TESTS:

An initial irritation screening test was performed to determine the highest non-ittitant concentration for the challenge phase of the study and suitable irritant concentrations for the induction phase. A concentration of 0.1% in the vehicle (water for injection) was selected for the intra-dermal induction phase, a 50% suspension of test substance in water for injection was selected for the topical induction phase and this was also the non-irritant concentration selected for the challenge application.

MAIN STUDY

A. INDUCTION EXPOSURE

Intra-dermal injections of test substance (0.1%) in water for injection, Freund's Complete Adjuvant (FCA) as a 50% v/v dilution with water for injection and the test substance (0.1% v/v) in FCA/water for injection (50:50) were administered to the scapular region of 10 animals. Five control animals received formulations where the vehicle replaced the test material in each of the above preparations. Skin reactions were assessed 24 and 48 hours after injection.

After seven days the topical induction phase was performed on the test animals: a 50% formulation of test material in water for injection was applied to the shaved inter-scapular area previously injected with the test substance and held in place for 48 hours with an occlusive dressing. Control animals received identical treatment without the test substance. After removal of the topical induction patch, animals were examined for erythema. Skin reactions were assessed immediately and 24 hours after removal of the dressings.

B. CHALLENGE EXPOSURE

21 days after the initial intra-dermal injections, a filter paper saturated with the primary challenge dose of 50% v/v test substance in water for injection was applied to a naive shaved site on the left flank of all test and control group animals and held in place for 24 hours with an occlusive dressing. The vehicle alone was similarly applied to the shaved right flank of each animal.

The primary challenge patch was removed and test sites were cleaned 24 hours after commencing application. The animals were examined for erythema as an indication of a sensitisation response. Skin reactions were assessed 24 and 48 hours after removal of the challenge dressing.

OTHER:

Mortality and toxic effects of treatment were recorded daily. Body weights were recorder pre-treatment, at start of application and at termination. Concurrent positive controls were not included with this study but the sensitivity of the test strain is tested by the laboratory twice a year and results confirming the suitability of the method were available from July 2005.

Results and discussion

Positive control results:
The positive control study, challenged with benzocaine in 40% ethanolic saline, produced sensitisation reactions in all animals confirming the suitability of the test methods and strain sensitivity.

In vivo (non-LLNA)

Resultsopen allclose all
Reading:
1st reading
Hours after challenge:
24
Group:
test group
Dose level:
50% v/v
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: 50% v/v. No with. + reactions: 0.0. Total no. in groups: 10.0. Clinical observations: None.
Reading:
2nd reading
Hours after challenge:
48
Group:
test group
Dose level:
50% v/v
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: 50% v/v. No with. + reactions: 0.0. Total no. in groups: 10.0. Clinical observations: None.
Reading:
1st reading
Hours after challenge:
24
Group:
negative control
Dose level:
50% v/v
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: 50% v/v. 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:
50% v/v
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: 50% v/v. No with. + reactions: 0.0. Total no. in groups: 5.0. Clinical observations: None.

Any other information on results incl. tables

Following intra-dermal injection at induction, all ten test group animals showed discrete or patchy erythema. Since the selected concentration for the topical induction application was non-irritating in the preliminary screen, the animals were pre-treated with sodium lauryl sulphate to induce a mild irritation response in the topical induction phase. There were no treatment-related mortalities and no toxic symptoms observed during the induction or challenge phases. Body weight gains were not affected by treatment.

There were no reactions at the vehicle application sites throughout the study.

Following the challenge application there were no skin reactions at any site treated with 50% copper dihydroxide suspension in water for injection.

Applicant's summary and conclusion

Interpretation of results:
not sensitising
Remarks:
Migrated information Criteria used for interpretation of results: EU
Conclusions:
Copper dihydroxide did not induce skin sensitisation in the guinea pig in the Magnusson and Kligman Maximisation test.
Classification according to Directive 67/548/EEC: Not classified.
Classification according to CLP/GHS: Not classified.
Executive summary:

A GLP-compliant guinea-pig maximisation test was carried out in accordance with the requirements of OECD Guideline 406 and EC Method B.6 without significant deviation. Groups of 10 test and 5 control animals were used. 21 days after the initial intra-dermal induction exposure to copper dihydroxide or the vehicle, the animals were subjected to a 24 hour challenge exposure with the test article under an occlusive dressing at a concentration of 50% v/v in water for injection. Sensitisation responses to the challenge procedure were evaluated 24 and 48 hours after the end of the exposure period.

No skin reactions were observed in the main study in any of the test animals or control animals. On this basis, copper dihydroxide is not classified as a skin sensitiser.