Copper dihydroxide

Skin sensitisation

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:

1992

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 406 (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

Test material information

Constituent 1

Reference substance name:

Copper dihydroxide

EC Number:

243-815-9

EC Name:

Copper dihydroxide

Cas Number:

20427-59-2

Molecular formula:

CuH4O2

IUPAC Name:

copper(2+) dihydroxide

Details on test material:

- Name of test material (as cited in study report): URA-08740-F-O-WP (chemical name copper hydroxide).
- Composition of test material, percentage of components: Not stated.
- Lot/batch No.: 250592

In vivo test system

Test animals

Species:

guinea pig

Strain:

other: Pirbright white

Sex:

male/female

Details on test animals and environmental conditions:

TEST ANIMALS
- Source: Firma Winkelmann, Versuchstierzucht, Gartenstr. 27, W-4799 Borchen.
- Age at study initiation: Not stated.
- Weight at study initiation: Males 377 - 500 grams. Females 337 - 487 grams.
- Housing: Collective housing up to a maximum of 5 animals per cage (Macrolon type IV).
- Diet (e.g. ad libitum): ad libitum.
- Water (e.g. ad libitum): ad libitum.
- Acclimation period: at least 5 days.

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22 +/- 3°C.
- Humidity (%): 30 - 70%.
- Air changes (per hr): Not stated.
- Photoperiod (hrs dark / hrs light): 12 hrs light/12 hrs dark.

Study design: in vivo (non-LLNA)

Induction

Induction 1

Route:

intradermal and epicutaneous

Vehicle:

other: aqua ad injectabilia and petrolatum

Induction 2

Concentration / amount:

Refer to details on study design.

Challenge

Challenge 1

Route:

epicutaneous, occlusive

Vehicle:

other: aqua ad injectabilia and petrolatum

Challenge 2

Concentration / amount:

Refer to details on study design.

No. of animals per dose:

Refer to details on study design.

Details on study design:

RANGE FINDING TESTS:

Intradermal Injection: The test article was diluted with aqua ad inject. and Freund's complete adjuvant (FCA) to give a final concentration of 5 %. Since this highest permissible concentration produced moderate irritation and ulceration, lower concentrations were tested. Six animals were employed for the concentration tested, skin reactions were recorded 48 h after treatment.

Dermal Application: The test article was incorporated in petrolatum to provide a final concentration of 50 % (w/w). A closed patch exposure was effected by means of an occlusive bandage. Two animals were employed and skin reactions were recorded 48 h post application.

MAIN STUDY:

The main study was performed on 20 test animals (10 male, 10 female) and 20 control animals (10 male, 10 female). The concentrations used were selected on the basis of the pilot study.

A. INDUCTION EXPOSURE

First stage - an area of 4 x 6 cm over the shoulders was clipped short with electric clippers and cleaned with 70 % (v/v) ethanol. Three pairs of intradermal injections were then made symmetrically in two rows on either side of the spine:

Test group:
1. 0.1 ml FCA 50 % (w/w) diluted in aqua ad inject.
2. 0.1 ml test article diluted in aqua ad inject, (final concentration: 0.1 %) .
3. 0.1 ml test article diluted in FCA/aqua ad inject, (final concentration: 0.1 %).

Control group:
1. 0.1 ml FCA 50 % (w/w) diluted in aqua ad inject.
2. 0.1 rnl aqua ad inject. (undiluted).
3. 0.1 ml aqua ad inject, 50 % (w/w) diluted in FCA.

Second stage - 7 days after the intradermal injections the dermal application was initiated. Because the test article was non-irritating at the highest permissible concentration in the pilot study, the area was reclipped and pretreated with 10 % sodium lauryl sulfate (SLS) in petrolatum 24 hours before application of the test article at a concentration of 50 % in petrolatum. The test article was spread in a thick layer [to saturation] over a 4 x 5 cm patch (filter paper). The latter was firmly secured over the previous injection sites by an occlusive dressing for 48 h. Control animals received a patch loaded with the vehicle alone.

B. CHALLENGE EXPOSURE

Both control and test animals were subjected to a challenge exposure 14 days after the second stage of induction. The challenge test was performed on a 5 x 5 cm clipped and shaved area on each flank. The maximal non-irritating concentration of the test article (50 % in petrolatum) was applied to the left flank and the vehicle to the right using the patch technique described for the range finding test. In each case the duration of exposure was 24 h under an occlusive dressing. 24 and 48 h after patch removal, allergic responses were evaluated on a numerical scale according to Draize.

Challenge controls:

Refer to details on study design.

Positive control substance(s):

no

Remarks:

The reaction to the positive control substances 2,4 dinitrochlorobenzene (extreme sensitizer) and benzocaine (moderate sensirizer) is tested periodically.

Results and discussion

In vivo (non-LLNA)

Results

Results 1

Reading:

1st reading

Hours after challenge:

24

Group:

test chemical

Dose level:

50% w/w

No. with + reactions:

0

Total no. in group:

20

Clinical observations:

None

Remarks on result:

other: Reading: 1st reading. . Hours after challenge: 24.0. Group: test group. Dose level: 50% w/w. No with. + reactions: 0.0. Total no. in groups: 20.0. Clinical observations: None.

Results 2

Reading:

2nd reading

Hours after challenge:

48

Group:

test chemical

Dose level:

50% w/w

No. with + reactions:

0

Total no. in group:

20

Clinical observations:

None

Remarks on result:

other: Reading: 2nd reading. . Hours after challenge: 48.0. Group: test group. Dose level: 50% w/w. No with. + reactions: 0.0. Total no. in groups: 20.0. Clinical observations: None.

Results 3

Reading:

1st reading

Hours after challenge:

24

Group:

negative control

Dose level:

50% w/w

No. with + reactions:

0

Total no. in group:

20

Clinical observations:

None

Remarks on result:

other: Reading: 1st reading. . Hours after challenge: 24.0. Group: negative control. Dose level: 50% w/w. No with. + reactions: 0.0. Total no. in groups: 20.0. Clinical observations: None.

Results 4

Reading:

2nd reading

Hours after challenge:

48

Group:

negative control

Dose level:

50% w/w

No. with + reactions:

0

Total no. in group:

20

Clinical observations:

None

Remarks on result:

other: Reading: 2nd reading. . Hours after challenge: 48.0. Group: negative control. Dose level: 50% w/w. No with. + reactions: 0.0. Total no. in groups: 20.0. Clinical observations: None.

Any other information on results incl. tables

Range Finding Test:

Intradermal:

5 %, 1 % and 0.5 %: Moderate irritation with test article-dependent discoloration of the partly indurated injection sites was observed.

0.25 %: Moderate irritation was observed.

0.10 %: No specific findings were observed.

Dermal:

No skin reactions were observed.

Main Study:

No skin reactions were observed in the main study in any of the 20 test animals (refer to Table 1) or 20 control animals (refer to Table 2).

The sensitisation rate at 24 hours was 0%.

Applicant's summary and conclusion

Interpretation of results:

not sensitising

Remarks:

Migrated information Criteria used for interpretation of results: EU

Conclusions:

No skin reactions were observed in the main study in any of the test or control animals (sensitisation rate at 24 hours 0%).
Classification according to Directive 67/548/EEC: Not classified.
Classification according to CLP/GHS: Not classified.

Executive summary:

A GLP-compliant test was carried out in accordance with the requirements of guideline OECD 406 (guinea-pig maximisation test) without significant deviation. Groups of 20 test and 20 control animals were used. Following induction exposure to copper dihydroxide or the vehicle, the animals were subjected two weeks later to a challenge exposure with the test article. 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 (sensitisation rate at 24 hours 0%). On this basis, copper dihydroxide is not classified as a skin sensitiser.