Disilver oxide

Eye irritation

Administrative data

Endpoint:

eye irritation: in vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1989-04-10 to 1989-04-10

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1989

Report date:

1989

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 405 (Acute Eye Irritation / Corrosion)

Deviations:

no

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Disilver oxide

EC Number:

243-957-1

EC Name:

Disilver oxide

Cas Number:

20667-12-3

Molecular formula:

Ag2O

IUPAC Name:

silver(1+) oxide

Details on test material:

- Name of test material (as cited in study report): silver(i)-oxide
- Physical state: brown-grey powder
- Stability under test conditions: Not indicated by the sponsor.
- Storage condition of test material: at room temperature

Test animals / tissue source

Species:

rabbit

Strain:

other: white russian (albino)

Details on test animals or tissues and environmental conditions:

TEST ANIMALS
- Source: ASTA Pharma AG, Bielefeld
- Age at study initiation: 10 months (males); 10 and 11 months (females)
- Weight at study initiation: 2.53 kg (males); 2.78 and 2.94 kg (females)
- Housing: stainless steel cages with grating floor, type ASTA, size: 48.5x40x36.5 cm (LxBxH), individually housing
- Diet: approx. 120 g/day x animal (Standard Diet, ssniff K, "Special diet for rabbits" supplied by ssniff Spezialfutter GmbH, D-4770 Soest)
- Water: ad libitum
- Acclimation period: 1 day

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 21.5 - 25.0
- Humidity (%): 40 - 60
- Photoperiod: 12 hours dark/light cycle

Test system

Vehicle:

not specified

Controls:

other: The right eye of each animal was not treated and was used as a control.

Amount / concentration applied:

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 0.08 g (representing a volume of about 0.1 ml) of the test substance were applied into the conjunctival sac of the left eye. Then both lids were briefly closed by gentle finger pressure.

Duration of treatment / exposure:

"lids were briefly closed"

Observation period (in vivo):

1 hour post application

Number of animals or in vitro replicates:

3 rabbits (1 male and 2 females)

Details on study design:

REMOVAL OF TEST SUBSTANCE
- Washing (if done): The treated eye was not rinsed.

SCORING SYSTEM: Signs of irritation on the cornea, iris and conjunctiva were assessed quantitatively and qualitatively using the DRAIZE scale. In addition, attention was paid to the occurrence of further reactions on the eyes (e.g. corrosive effect) and to clinical symptoms (systemic toxic effects).

TOOL USED TO ASSESS SCORE: The treated eyes were examined using a Cliptrix pencil light (supplied by Varta, Hannover, No. 645).

EVALUATION: An irritation index was not determined because of the corrosive effects.

Results and discussion

In vivo

Results

Results 1

Irritation parameter:

cornea opacity score

Remarks:

(opacity)

Basis:

mean

Time point:

other: 1 hour after treatment

Score:

4

Max. score:

4

Reversibility:

other: animals were sacrificed

Results 2

Irritation parameter:

cornea opacity score

Remarks:

(area of cornea involved)

Basis:

mean

Time point:

other: 1 hour after treatment

Score:

4

Max. score:

4

Reversibility:

other: animals were sacrificed

Remarks on result:

positive indication of irritation

Results 3

Irritation parameter:

iris score

Basis:

mean

Time point:

other: 1 hour after treatment

Reversibility:

other: animals were sacrificed

Remarks on result:

other: evaluation not possible

Results 4

Irritation parameter:

conjunctivae score

Remarks:

(redness)

Basis:

mean

Time point:

other: 1 hour after treatment

Reversibility:

other: animals were sacrificed

Remarks on result:

other: evaluation not possible

Results 5

Irritation parameter:

conjunctivae score

Remarks:

(discharge)

Basis:

mean

Time point:

other: 1 hour after treatment

Score:

2

Max. score:

3

Reversibility:

other: animals were sacrificed

Remarks on result:

positive indication of irritation

Results 6

Irritation parameter:

chemosis score

Basis:

mean

Time point:

other: 1 hour after treatment

Score:

1.33

Max. score:

4

Reversibility:

other: animals were sacrificed

Remarks on result:

positive indication of irritation

Irritant / corrosive response data:

The application of 0.08 g silver(I)-oxide into one conjunctival sac each of three rabbits caused severe changes. Because of the physical properties of the test substance the dose had to be limited to the a.m. level.
The cornea of all animals showed opacity of the whole corneal area (grade 4). The upper corneal area was olive-green discoloured.
An evaluation of the iris was impossible.
The conjunctiva of all animals was olive-green discoloured and the nictitating membrane of one animal parchment-like thinned. In addition, slight or obvious swelling with partial eversion of lids (grades 1 or 2) was observed.
Discharge with moistening of considerable parts around the eye (grade 3) was detected in two animals.

Other effects:

The animals were sacrificed painlessly for reasons of animal protection.
In general, identical histopathological findings were present in all three animals. Severe acute coagulation necrosis of the mucosa and submucosal tissue, incl. glandular tissue, with complete loss of the epithelium and moderate edema were observed in conjunctiva and nictitating membrane. In the cornea complete loss of the corneal epithelium and hyalinization of the superficial layers of the corneal stroma were found.

There were no systemic toxic effects after conjunctival application of the test substance.

Any other information on results incl. tables

A full evaluation of iris anc conjunctivae score was not possible (due to the severity of the effects the animals had to be sacrificed before conclusion of the normal observation period).

Applicant's summary and conclusion

Interpretation of results:

Category 1 (irreversible effects on the eye) based on GHS criteria

Remarks:

Silver(I)-oxide is corrosive to the eye.

Conclusions:

Silver(I)-oxide is corrosive in this test system.