Dicopper oxide

Skin irritation / corrosion

Administrative data

Endpoint:

skin irritation: in vivo

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1988

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 404 (Acute Dermal Irritation / Corrosion)

Deviations:

yes

Remarks:

(Refer to 'Principles of Method')

Principles of method if other than guideline:

Compliance with OECD Test Guideline 404 (adopted 24 April 2002) was checked. The following information was not included in the study report:
• The technique of patch site preparation,
• The method used to remove residual test substance,
• Details of test animals (source; age of animals at the start of the study; number of animals of each sex; individual animal weight at the start and
conclusion of the test),
• The rationale for in vivo testing,
• Test substance purity,
• Scores after 48 h are not presented.
These deviations however are not considered to have influenced the outcome or the integrity of the study.

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Dicopper oxide

EC Number:

215-270-7

EC Name:

Dicopper oxide

Cas Number:

1317-39-1

Molecular formula:

Cu2O

IUPAC Name:

copper (I) oxide

Details on test material:

Lot/batch number: Not available.
Description: An orange fine crystalline powder (inscription on bottle: 84.5 p.c Cu.)
Purity: From information provided, assumed to be 84.5%.
Stability: Not available.

Test animals

Species:

rabbit

Strain:

New Zealand White

Details on test animals or test system and environmental conditions:

Source: No information provided.
Sex: No information provided.
Age at study initiation: Age not provided.
Weight at study initiation: Animals weighed about 3.0 kg.

Test system

Type of coverage:

semiocclusive

Preparation of test site:

other: Irritation of both abraded and intact skin was investigated.

Vehicle:

water

Remarks:

Test 1: Water. Test 2: Tylose.

Controls:

other: Treated and untreated skin sites in the same animals were compared.

Amount / concentration applied:

Amount of test substance applied: 0.5 ml.
Concentration in vehicle: Not reported.
Total volume applied: Not reported.

Duration of treatment / exposure:

Duration of exposure: 4 hours.

Observation period:

Postexposure period: 7 days.

Number of animals:

Number of animals per group: 10 rabbits were used (5 in each test).

Details on study design:

Preparation of test substance: The report indicates that “0.5 ml of the test substance was applied with gauze squares of the size of 2.5 x 2.5 cm on the skin”.
The following information is also given:
Test 1 (5 animals): the substance was tested undiluted as a paste (applied as a powder and wetted with water 1:1).
Test 2 (5 animals): the substance was tested as a 10 % suspension in Tylose.

Occlusion: The gauze patches were fixed with the help of adhesive plaster (assumed to be semi-occlusive).

Removal of test substance: The method to remove residual test substances is not given.

Results and discussion

In vivo

Results

Results 1

Irritation parameter:

erythema score

Remarks:

(Intact skin).

Basis:

mean

Remarks:

for 5 animals

Time point:

24 h

Score:

0

Max. score:

0

Reversibility:

other: no effect

Remarks on result:

other: No reading was taken at 48 hours.

Results 2

Irritation parameter:

erythema score

Remarks:

(Intact skin).

Basis:

mean

Remarks:

for 5 animals

Time point:

72 h

Score:

0

Max. score:

0

Reversibility:

other: no effect

Remarks on result:

other: No reading was taken at 48 hours.

Results 3

Irritation parameter:

edema score

Remarks:

(Intact skin).

Basis:

mean

Remarks:

for 5 animals

Time point:

24 h

Score:

0

Max. score:

0

Reversibility:

other: no effect

Remarks on result:

other: No reading was taken at 48 hours.

Results 4

Irritation parameter:

edema score

Remarks:

(Intact skin).

Basis:

mean

Remarks:

for 5 animals

Time point:

72 h

Score:

0

Max. score:

0

Reversibility:

other: no effect

Remarks on result:

other: No reading was taken at 48 hours.

Any other information on results incl. tables

Reversibility: Slight erythema observed in the abraded skin of two animals receiving 0.5g of cuprous oxide at the 24 hour reading had resolved by 72 hours.

Overall result: Slight erythema was observed in the abraded skin of 2/5 animals receiving 0.5 g of cuprous oxide moistened with water at the 24 hour reading only.

No dermal irritation was seen on the intact test sites of any of the ten rabbits tested, at any time-point.

Refer to Table 1 and Table 2 below for dermal irritation scores. Table 1. Dermal irritation scores (Cuprous oxide - wetted 1:1 with water).

Response		Animal number
Erythema	Reading	1		2		3		4		5
		I	A	I	A	I	A	I	A	I	A
	24 h	0	0	0	0	0	0	0	0	0	0
	72 h	0	0	0	0	0	0	0	0	0	0
	7 days	0	0	0	0	0	0	0	0	0	0
Mean scores (24 and 72 h)		0	0	0	0	0	0	0	0	0	0
Oedema	24 h	0	0	0	1	0	0	0	1	0	0
	72 h	0	0	0	0	0	0	0	0	0	0
	7 days	0	0	0	0	0	0	0	0	0	0
Mean scores (24 and 72 h)		0	0	0	0.5	0	0	0	0.5	0	0

I = Intact, A = Abraded

Table 2. Dermal irritation scores (Cuprous oxide - 10% suspension in Tylose).

 

Response		Animal number
Erythema	Reading	1		2		3		4		5
		I	A	I	A	I	A	I	A	I	A
	24 h	0	0	0	0	0	0	0	0	0	0
	72 h	0	0	0	0	0	0	0	0	0	0
	7 days	0	0	0	0	0	0	0	0	0	0
Mean scores (24 and 72 h)		0	0	0	0	0	0	0	0	0	0
Oedema	24 h	0	0	0	0	0	0	0	0	0	0
	72 h	0	0	0	0	0	0	0	0	0	0
	7 days	0	0	0	0	0	0	0	0	0	0
Mean scores (24and 72 h)		0		0	0	0	0	0	0	0	0

I = Intact, A = Abraded

Applicant's summary and conclusion

Interpretation of results:

not irritating

Remarks:

Migrated information Criteria used for interpretation of results: EU

Conclusions:

A single 4-hour, semi-occluded application of the undiluted test substance to the intact skin of five rabbits produced no evidence of skin irritation.
In this study, cuprous oxide did not meet the criteria for classification for dermal irritation according to Annex VI of Commission Directive 2001/59/EC.

Executive summary:

Materials and Methods: This study was conducted according to GLP. A number of deviations from OECD Test Guideline 404 'Acute Dermal Irritation/Corrosion' (adopted 24 April 2002) occurred. These deviations are not considered to have influenced the outcome or the integrity of the study.

Test 1: An amount of 0.5 g of cuprous oxide, moistened with water, was applied to the shaven, intact or abraded dorsal skin of 5 New Zealand White rabbits under a semi occlusive bandage.

Test 2: A ten percent suspension of cuprous oxide in Tylose (the volume is unclear from the report), was applied to the shaven, intact or abraded dorsal skin of 5 New Zealand White rabbits under a semi occlusive bandage.

After a 4 h exposure period the bandages were removed and residual test substance was removed. The study report indicates that local reactions were evaluated after 1 hour, and every 24 hours thereafter up to 7 days. However, only scores after 24h, 72h, and 7 days are presented.

Results and Discussion:

Sight erythema, was observed in the abraded skin of 2/5 animals receiving0.5 g of cuprous oxide moistened with waterat the 24 hour reading only.

No dermal irritation was seen on the intact test sites of any of the ten rabbits tested, at any time-point.