Cyanamide

Eye irritation

Administrative data

Endpoint:

eye irritation: in vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1991

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1991

Report date:

1991

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

EPA OPP 81-4 (Acute Eye Irritation)

Deviations:

no

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Cyanamide

EC Number:

206-992-3

EC Name:

Cyanamide

Cas Number:

420-04-2

Molecular formula:

CH2N2

IUPAC Name:

cyanamide

Test material form:

other: aqueous solution

Details on test material:

- Test substance: Cyanamid L500 (supplied as aqueous solution)
- Purity: 49 % (w/w), equivalent to 520 g/L of active substance Hydrogen cyanamide
- Appearance: Clear colourless liquid
- Lot/Batch number: 06/20/91

Test animals / tissue source

Species:

rabbit

Strain:

New Zealand White

Details on test animals or tissues and environmental conditions:

- Source: Foxfields Rabbits; Petersfield, Hampshire, England
- Body weight and age: Body weight 3 kg, approximately 14 weeks old

Test system

Vehicle:

unchanged (no vehicle)

Controls:

yes

Amount / concentration applied:

A single dose of 0.1 mL of the test substance

Duration of treatment / exposure:

Not indicated

Observation period (in vivo):

Examination of the eye was made 1 hour as well as 1, 2, 3, 4 and 7 day after the end of exposure.

Number of animals or in vitro replicates:

1 rabbit

Results and discussion

In vivo

Results

Results 1

Irritation parameter:

cornea opacity score

Basis:

animal #1

Time point:

24/48/72 h

Score:

2

Max. score:

4

Reversibility:

fully reversible within: 7 days

Results 2

Irritation parameter:

cornea opacity score

Basis:

animal #1

Time point:

other: 96 hours

Score:

1

Max. score:

4

Reversibility:

fully reversible within: 7 days

Results 3

Irritation parameter:

cornea opacity score

Basis:

animal #1

Time point:

7 d

Score:

0

Max. score:

4

Results 4

Irritation parameter:

iris score

Basis:

animal #1

Time point:

24 h

Score:

0

Max. score:

2

Results 5

Irritation parameter:

iris score

Basis:

animal #1

Time point:

other: 48, 72 hours

Score:

1

Max. score:

2

Reversibility:

fully reversible within: 96 hours

Results 6

Irritation parameter:

iris score

Basis:

animal #1

Time point:

other: 96, 7 days

Score:

0

Max. score:

2

Results 7

Irritation parameter:

conjunctivae score

Remarks:

: redness

Basis:

animal #1

Time point:

other: 1, 24, 48, 72 hours

Score:

2

Max. score:

3

Reversibility:

fully reversible within: 7 days

Remarks on result:

other: At 48 and 72 hours also an haemorrhage of the nictating membrane was observed.

Results 8

Irritation parameter:

conjunctivae score

Remarks:

: redness

Basis:

animal #1

Time point:

other: 96 hours

Score:

1

Max. score:

3

Reversibility:

fully reversible within: 7 days

Remarks on result:

other: An haemorrhage of the nictating membrane was also observed.

Results 9

Irritation parameter:

conjunctivae score

Remarks:

: redness

Basis:

animal #1

Time point:

other: 7 days

Score:

0

Max. score:

3

Results 10

Irritation parameter:

chemosis score

Basis:

animal #1

Time point:

other: 1, 24 hours

Score:

3

Max. score:

4

Reversibility:

fully reversible within: 7 days

Results 11

Irritation parameter:

chemosis score

Basis:

animal #1

Time point:

other: 48, 72 hours

Score:

2

Max. score:

4

Reversibility:

fully reversible within: 7 days

Results 12

Irritation parameter:

chemosis score

Basis:

animal #1

Time point:

other: 96 hours

Score:

1

Max. score:

4

Reversibility:

fully reversible within: 7 days

Results 13

Irritation parameter:

chemosis score

Basis:

animal #1

Time point:

other: 7 days

Score:

0

Max. score:

4

Results 14

Irritation parameter:

cornea opacity score

Basis:

mean

Time point:

24/48/72 h

Score:

2

Max. score:

4

Results 15

Irritation parameter:

iris score

Basis:

mean

Time point:

24/48/72 h

Score:

0.67

Max. score:

2

Results 16

Irritation parameter:

conjunctivae score

Remarks:

: redness

Basis:

mean

Time point:

24/48/72 h

Score:

2

Max. score:

3

Results 17

Irritation parameter:

chemosis score

Basis:

mean

Time point:

24/48/72 h

Score:

2.3

Max. score:

4

Irritant / corrosive response data:

One hour after the end of exposure the cornea was dull and by the following day an opacity had developed which persisted for the following three days and resolved seven days after instillation. Iritis was observed two and three days after the end of exposure. A diffuse conjunctiva redness was accompanied by swelling, the lids half closed and a copious discharge.

Other effects:

There was also evidence of haemorrhage on the nictating membrane.

Any other information on results incl. tables

Table 1: Results of the primary eye irritation test in a rabbit with cyanamide:

Time	Cornea	Iris	Conjunctiva
			redness	chemosis	discharge
1 hour	D*	0	2	3	3
24 hours	2	0	2	3	3
48 hours	2	1	2^+	2	2
72 hours	2	1	2^+	2	2
96 hours	1	0	1^+	1	1
7 days	0	0	0	0	0
mean scores 24-72 h	2	0.67	2	2.3

D = Dulling of the cornea

⁺haemorrhage of nictating membrane

Applicant's summary and conclusion

Interpretation of results:

Category 2 (irritating to eyes) based on GHS criteria

Conclusions:

Cyanamide was found to be an eye irritant to one New Zealand white rabbit under the test conditions.

Executive summary:

The test substance, Cyanamid L500 (supplied as aqueous solution) was applied in a single dose of a 0.1 mL aliquot into the lower everted lid of one eye of an adult New Zealand white rabbit (body weight 3 kg, 14 weeks old). The contralateral eye remained untreated and served as a control. Examination of the eye was made 1 hour as well as 1, 2, 3, 4 and 7 day after the end of exposure. The animal was observed daily for clinical signs and behaviour.

One hour after the end of exposure the cornea was dull and by the following day an opacity had developed which persisted for the following three days and resolved seven days after instillation. Iritis was observed two and three days after the end of exposure. A diffuse conjunctiva redness was accompanied by swelling with the lids half closed and a copious discharge. There was also evidence of haemorrhage on the nictating membrane. All lesions had resolved seven days after the end of exposure. The mean scores (24- 72 hours) for the examined parameters were as follows: Cornea:2, iris: 0.67, conjunctiva redness: 2, chemosis: 2.3.

Due to the severity of the reaction no further animals were exposed to the test substance.

Under the test conditions the test substance examined in a rabbit can be considered as an eye irritant.