Zinc sulphate

Eye irritation

Administrative data

Endpoint:

eye irritation: in vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

Not reported

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1999

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 405 (Acute Eye Irritation / Corrosion)

Deviations:

not specified

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method B.5 (Acute Toxicity: Eye Irritation / Corrosion)

Deviations:

not specified

Principles of method if other than guideline:

Not applicable

GLP compliance:

not specified

Test material

Test material information

Constituent 1

Reference substance name:

Zinc sulphate

EC Number:

231-793-3

EC Name:

Zinc sulphate

Cas Number:

7733-02-0

Molecular formula:

H2O4S.Zn

IUPAC Name:

zinc sulfate

Details on test material:

- Name of test material (as cited in study report): zinc sulphate (ZnSO4.7H2O)

Test animals / tissue source

Species:

rabbit

Strain:

New Zealand White

Details on test animals or tissues and environmental conditions:

No information

Test system

Vehicle:

unchanged (no vehicle)

Controls:

yes, concurrent no treatment

Amount / concentration applied:

Approximately 98.1 mg of the test material

Duration of treatment / exposure:

Single instillation into the conjuctival sac of the eye, no eye wash

Observation period (in vivo):

At 1, 24, 48 and 72 hours, 7, 14 and 21 days after exposure.

Number of animals or in vitro replicates:

Three male animals

Details on study design:

No further details

Results and discussion

In vivo

Results

Results 1

Irritation parameter:

conjunctivae score

Remarks:

redness

Basis:

mean

Time point:

24 h

Score:

ca. 2

Max. score:

3

Reversibility:

not specified

Remarks on result:

probability of severe irritation

Results 2

Irritation parameter:

conjunctivae score

Remarks:

redness

Basis:

mean

Time point:

48 h

Score:

2.7

Max. score:

3

Reversibility:

not specified

Remarks on result:

probability of severe irritation

Results 3

Irritation parameter:

conjunctivae score

Remarks:

redness

Basis:

mean

Time point:

72 h

Score:

ca. 2.7

Max. score:

3

Reversibility:

not specified

Remarks on result:

probability of severe irritation

Results 4

Irritation parameter:

chemosis score

Basis:

mean

Time point:

24 h

Score:

ca. 2

Max. score:

4

Reversibility:

not specified

Remarks on result:

probability of moderate irritation

Results 5

Irritation parameter:

chemosis score

Basis:

mean

Time point:

48 h

Score:

ca. 2.7

Max. score:

4

Reversibility:

not specified

Remarks on result:

probability of severe irritation

Results 6

Irritation parameter:

chemosis score

Basis:

mean

Time point:

72 h

Score:

ca. 3.7

Max. score:

4

Reversibility:

not specified

Remarks on result:

probability of severe irritation

Results 7

Irritation parameter:

cornea opacity score

Basis:

mean

Time point:

24/48/72 h

Remarks on result:

not measured/tested

Results 8

Irritation parameter:

iris score

Basis:

mean

Time point:

24/48/72 h

Remarks on result:

not measured/tested

Irritant / corrosive response data:

Corneal injury was seen as slight dulling of the normal lustre (opacity grade 0) and/or epithelial damage (10% of the corneal area) in two animals. This injury had resolved within 24 hours in one animal and within 72 hours in the other animal.
Irritation of the conjuctivae was seen as redness (mean scores over 24-72 hours 2, 2.7 and 2.7), chemosis (mean scores 2, 2.7 and 3.7) and discharge.
Yellow/white spots were observed in the tissue of the lower eyelid, nictitating membrane and/or sclera in all animals from day 7 until termination. These spots were described as signs of necrosis and consisted of encapsulated material of unknown origin which caused protrusions at termination of the study.

Other effects:

Reduced elasticity of the eyelids was noted in one animal, 72 hours and 7 days after instillation.

Any other information on results incl. tables

None       

Applicant's summary and conclusion

Interpretation of results:

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

Conclusions:

Based on the degree and persistence of the corneal injury, zinc sulphate is considered to cause severe ocular irritation

Executive summary:

In a well-performed eye irritation/corrosion study, conducted according to Directive 92/69/EEC B.5 and OECD guideline 405, three male New Zealand White rabbits were treated by instillation of approximately 98.1 mg of zinc sulphate (ZnSO_4.7H₂O) into the conjuctival sac of one eye. The other eye remained untreated and served as control. The eyes (unrinsed) were examined at 1, 24, 48 and 72 hours and 7, 14 and 21 days after instillation.

No symptoms of systemic toxicity were observed and no mortality occurred.

Corneal injury was seen as slight dulling of the normal lustre (opacity grade 0) and/or epithelial damage (10% of the corneal area) in two animals. This injury had resolved within 24 hours in one animal and within 72 hours in the other animal.

Irritation of the conjuctivae was seen as redness (mean scores over 24-72 hours 2, 2.7 and 2.7), chemosis (mean scores 2, 2.7 and 3.7) and discharge.

Yellow/white spots were observed in the tissue of the lower eyelid, nictitating membrane and/or sclera in all animals from day 7 until termination. These spots were described as signs of necrosis and consisted of encapsulated material of unknown origin which caused protrusions at termination of the study. Reduced elasticity of the eyelids was noted in one animal, 72 hours and 7 days after instillation.

Based on the degree and persistence of the corneal injury, zinc sulphate is considered to cause severe ocular irritation.