Cobalt dinitrate

Eye irritation

Administrative data

Endpoint:

eye irritation: in vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2012-12-03 to 2012-12-24

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2013

Report date:

2013

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 405 (Acute Eye Irritation / Corrosion)

Version / remarks:

2002-04-24

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Remarks:

signed 2012-11-30

Test material

Test material information

Constituent 1

Reference substance name:

Cobalt dinitrate

EC Number:

233-402-1

EC Name:

Cobalt dinitrate

Cas Number:

10141-05-6

Molecular formula:

Co.2NO3

IUPAC Name:

cobalt(2+) dinitrate

Test material form:

solid: particulate/powder

Remarks:

migrated information: powder

Details on test material:

- Name of test material (as cited in study report): Cobalt dinitrate
- Physical state: crystalline powder, red-brown
- Storage condition of test material: room temperature in the dark

Test animals / tissue source

Species:

rabbit

Strain:

New Zealand White

Details on test animals or tissues and environmental conditions:

TEST ANIMALS - New Zealand White (Hsdlf:NZW) strain rabbit
- Source: Harlan Laboratories UK Ltd., Leicestershire, UK
- Age at study initiation: twelve to twenty weeks old
- Weight at study initiation: 2.47 kg
- Housing: the animal was housed in suspended cage.
- Diet (ad libitum): 2930C Teklad Global Rabbit diet supplied by Harlan Laboratories UK Ltd., Oxon, UK
- Water (ad libitum): mains drinking water
- Acclimation period: at least five days

The animal was provided with environmental enrichment items which were considered not to contain any contaminant of a level that might have affected the purpose or integrity of the study.

ENVIRONMENTAL CONDITIONS
- Temperature: 17 to 23°C
- Relative humidity: 30 to 70%
- Air exchange: at least fifteen changes per hour
- Photoperiod (hrs dark / hrs light): 12/12

Test system

Vehicle:

unchanged (no vehicle)

Controls:

no

Amount / concentration applied:

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): a volume of 0.1 mL of the test item, which was found to weigh approximately 96 mg (as measured by gently compacting the required volume into an adapted syringe) was placed into the conjunctival sac of the right eye, formed by gently pulling the lower lid away from the eyeball. The upper and lower eyelids were held together for about one second immediately after treatment, to prevent loss of the test item, and then released. The left eye remained untreated and was used for control purposes.
For the purpose of the study the test item was ground before use.

Duration of treatment / exposure:

not applicable

Observation period (in vivo):

approximately 1 hour and 24, 48 and 72 hours following treatment as well as on days 7, 14 and 21

Number of animals or in vitro replicates:

1 male rabbit

Details on study design:

Immediately before the start of the test, both eyes of the provisionally selected test rabbit were examined for evidence of ocular irritation or defect with the aid of a light source from a standard ophthalmoscope. An animal free of ocular damage was used.

One rabbit was treated. Immediately after administration of the test item, an assessment of the initial pain reaction was made according to the six point scale (please refer to table 2 in the field "Any other information on materials and methods incl. tables" below).
After consideration of the ocular responses produced in this animal, no additional animals were treated.

SCORING SYSTEM: according to the Draize scale
Any other ocular effects were also noted.
Any clinical signs of toxicity, if present, were also recorded.
The animal's body weight was recorded on Day 0 (the day of dosing) and at the end of the observation period.

TOOL USED TO ASSESS SCORE: examination of the eye was facilitated by the use of the light source from a standard ophthalmoscope. The presence of corneal opacity at the 21-Day observation was confirmed by fluorescein staining.

Results and discussion

In vivo

Results

Results 1

Irritation parameter:

cornea opacity score

Basis:

mean

Remarks:

animal #1

Time point:

24/48/72 h

Score:

1

Max. score:

4

Reversibility:

not fully reversible within: 21 days

Remarks on result:

other: Initial pain reaction was moderate initial pain. Slight corneal opacity was observed 1 hour after administration. One quarter to greater than half but less than three quarters of the corneal area showed opacity during the study.

Results 2

Irritation parameter:

iris score

Basis:

mean

Remarks:

animal #1

Time point:

24/48/72 h

Score:

1

Max. score:

2

Reversibility:

fully reversible within: 14 days

Remarks on result:

other: Slight iridial inflammation was observed 1 hour after administration as well as 7 and 14 days after administration. Slight to severe discharge was observed throughout the study.

Results 3

Irritation parameter:

conjunctivae score

Basis:

mean

Remarks:

animal #1

Time point:

24/48/72 h

Score:

2

Max. score:

3

Reversibility:

not fully reversible within: 21 days

Remarks on result:

other: Moderate conjunctival redness was observed throughout the whole observation period. Red coloured staining of fur around treated eye was observed throughout the observation period.

Results 4

Irritation parameter:

chemosis score

Basis:

mean

Remarks:

animal #1

Time point:

24/48/72 h

Score:

3

Max. score:

4

Reversibility:

not fully reversible within: 21 days

Remarks on result:

other: Moderate chemosis was observed throughout the whole observation period. Vascularization, with localized ingrowth of vessels, approximately 3 mm onto the cornea along the top, left of the eye was observed 7 days after administration.

Results 5

Remarks on result:

other: Vascularisation, with generalized ingrowth of vessels, approximately 6 mm onto the cornea was observed 14 days after administration.

Results 6

Remarks on result:

other: Vascularisation, with a localized ingrowth of vessels, approx. 4 mm onto the cornea along the bottom of the eye was observed 21 days after administration. Alopecia around the treated eye was observed 7, 14 and 21 days after administration.

Irritant / corrosive response data:

Red coloured staining of the fur was noted around the treated eye throughout the study.
Diffuse corneal opacity was noted in the treated eye one hour after treatment, at the 24, 48 and 72-Hour observations with translucent corneal opacity at the 7 and 14-Day observations and diffuse corneal opacity at the 21-Day observation. Vascularisation, with a localized ingrowth of vessels approximately 3 mm onto the cornea along the top, left of the treated eye, was noted at the 7-Day observation. Vascularisation, with a generalized ingrowth of vessels approximately 6 mm onto the cornea, was noted in the treated eye at the 14-Day observation. Vascularisation, with a localized ingrowth of vessels approximately 4 mm onto the cornea and along the bottom of the treated eye, was noted at the 21-Day observation.
Iridial inflammation was noted in the treated eye one hour after treatment, at the 24, 48 and 72-Hour, 7 and 14-Day observations.
Moderate conjunctival irritation was noted in the treated eye one hour after treatment with severe conjunctival irritation noted at the 24, 48 and 72-Hour observations and moderate conjunctival irritation noted at the 7, 14 and 21-Day observations.
Alopecia around the treated eye was noted at the 7, 14 and 21-Day observations.
The persistence of reactions in the treated eye at the 21-Day observation was considered to be indicative of irreversible ocular damage.

Other effects:

- Body weight: the animal showed expected gain in body weight during the study.

Applicant's summary and conclusion

Interpretation of results:

Category 1 (irreversible effects on the eye)

Conclusions:

The test material caused irreversible ocular damage.
According to the EC Regulation No. 1272/2008 and subsequent regulations, the substance is classified as Category 1.