(1,4,5,6-tetrahydro-4,6-dioxopyrimidin-2-yl)cyanamide

Eye irritation

Administrative data

Endpoint:

eye irritation: in vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

From 15 January 1992 to 19 January 1992

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1992

Report date:

1992

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 405 (Acute Eye Irritation / Corrosion)

Version / remarks:

1987

Test guideline 2

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

84/449/EEC

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

(1,4,5,6-tetrahydro-4,6-dioxopyrimidin-2-yl)cyanamide

EC Number:

259-467-6

EC Name:

(1,4,5,6-tetrahydro-4,6-dioxopyrimidin-2-yl)cyanamide

Cas Number:

55067-10-2

Molecular formula:

C5H4N4O2

IUPAC Name:

(1,4,5,6-tetrahydro-4,6-dioxopyrimidin-2-yl)cyanamide

Test material form:

solid: particulate/powder

Details on test material:

Test material: CYDI ((1,4,5,6-Tetrahydro-4,6-dioxopyrimidin-2-yl)cyanamide)
Description: Off-white powder
Storage: In original container at room temperature
Molecular formula: C5H4N4O2

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Description: off-white powder
- Sponsor's identification: CYDI

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: room temperature
- Container: white plastic jar (x2)
- Data relating to the identity, purity and stability of the test material are the responsibility of the sponsor.

Test animals / tissue source

Species:

rabbit

Strain:

New Zealand White

Details on test animals or tissues and environmental conditions:

TEST ANIMALS
- Source: David Percival Ltd., Moston, Sandbach, Cheshire, U.K.
- Age at study initiation: twelve to sixteen weeks old
- Weight at study initiation: 2.67 - 2.82 kg
- Housing: individual housing in suspended metal cages
- Diet (e.g. ad libitum): Spillers Rabbit Diet, Dalgety Agriculture Ltd., Almondsbury, Bristol; free access was allowed throughout the study
- Water (e.g. ad libitum): Spillers Rabbit Diet, Dalgety Agriculture Ltd., Almondsbury, Bristol; free access was allowed throughout the study
- Acclimation period: five days each animal

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 18-21°C
- Humidity (%): 49-56%
- Air changes (per hr): approximately 15 changes per hour
- Photoperiod (hrs dark / hrs light): continuous 12 hours light and 12 hours of darkness

Test system

Vehicle:

unchanged (no vehicle)

Controls:

yes, concurrent no treatment

Amount / concentration applied:

0.1 ml of the test material, approximately 69 mg

Duration of treatment / exposure:

72h

Observation period (in vivo):

Assessment of ocular damage/irritation was made approximately 1h, 24h, 48h and 72 h following treatment.

Number of animals or in vitro replicates:

3

Details on study design:

TREATMENT WITH TEST SUBSTANCE:
A volume of 0.1 ml of the test material, which was found to weigh approximately 69 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 imediately after application, to prevent loss of the test material, and then released. The left eye remained untreated and was used for control purposes. Immediately after administration of the test material, an assessment of the initial pain reaction was made.
In order to minimise pain on instillation of the test material, one drop of local anaesthetic ('Ophthaine', 0.5% proxymetacaine hydrochloride, E.R. Squibb & Sons, Limited Hounslow, iliddlesex, U.K.) was instilled into both eyes of these animals 1 - 2 minutes before treatment.

TOOL USED TO ASSESS SCORE: standard ophthalmoscope

SCORING SYSTEM: Assessment of ocular damage/irritation ras made approximately 1 hour and 24, 48 and 72 hours following treatment, according to the numerical evaluation given in Table 1 (from Draize J.H. 1959, Association of Food and Drug Officials of the United States, Austin, Texas, 'The Appraisal of the Safety of Chemicals in Foods, Drugs and Cosmetics").

INTERPRETATION OF RESULTS:

The numerical values corresponding to each animal, tissue and observation time were recorded. The data relating to the conjunctivae were designated by the letters A (redness), B (chemosis) and C (discharge), those relating to the iris designated by the letter D and those relating to the cornea by the letters E (degree of opacity) and F (area of opacity). For each tissue the score was calculated as follows:
Score for conjuctivae = (A+B+C) x 2
Score for iris = D x 5
Score for cornea = (E x F) x 5

Using the numerical data obtained a modified version of the system described by Kay J.H. and Calandra J.C., J. Soc. Cosmet. Chem., 1962 13 281-289 was used to classify the ocular irritancy potential of the test material (Table 2).

Results and discussion

In vivo

Results

Results 1

Irritation parameter:

cornea opacity score

Basis:

animal: #1; #2; #3

Time point:

24 h

Score:

1

Max. score:

4

Reversibility:

fully reversible within: 48h

Results 2

Irritation parameter:

cornea opacity score

Basis:

animal: #1; #2; #3

Time point:

other: 48h, 72h

Score:

0

Max. score:

4

Reversibility:

fully reversible within:

Results 3

Irritation parameter:

iris score

Basis:

animal: #1; #2; #3

Time point:

24/48/72 h

Score:

0

Max. score:

2

Reversibility:

fully reversible

Results 4

Irritation parameter:

conjunctivae score

Basis:

animal: #1; #3

Time point:

24 h

Score:

1

Max. score:

3

Reversibility:

fully reversible within: 48h

Results 5

Irritation parameter:

conjunctivae score

Basis:

animal: #1; #3

Time point:

other: 48h, 72h

Score:

0

Max. score:

3

Reversibility:

fully reversible within: 48h

Results 6

Irritation parameter:

conjunctivae score

Basis:

animal #2

Time point:

24 h

Score:

2

Max. score:

3

Reversibility:

fully reversible within: 72h

Results 7

Irritation parameter:

conjunctivae score

Basis:

animal #2

Time point:

48 h

Score:

1

Max. score:

3

Reversibility:

fully reversible within: 72h

Results 8

Irritation parameter:

conjunctivae score

Basis:

animal #2

Time point:

72 h

Score:

0

Max. score:

3

Reversibility:

fully reversible within: 72h

Results 9

Irritation parameter:

chemosis score

Basis:

animal: #1; #2; #3

Time point:

24 h

Score:

1

Max. score:

4

Reversibility:

fully reversible within: 48h

Results 10

Irritation parameter:

chemosis score

Basis:

animal: #1; #2; #3

Time point:

other: 48/72h

Score:

0

Max. score:

4

Reversibility:

fully reversible within: 48h

Irritant / corrosive response data:

Diffuse corneal opacity was noted in all treated eyes one and 24 hours after treatment. No other adverse corneal effects were noted.

Other effects:

Residual test material was noted around the treated eyes of all animals during the study.
Iridial inflammation was noted in all treated eyes one hour after treatment. No other adverse iridial effects were noted.
Moderate conjunctival irritation was noted in all treated eyes one hour after treatment with minimal to moderate conjunctival irritation at the 24-hour observation. Minimal conjunctival irritation was noted in one treated eye at the 48-hour observation.
All treated eyes appeared normal 72 hours after treatment.

Any other information on results incl. tables

Individual scores are provided below for eye irritation

	Animal # 1 (female)				Animal # 2 (female) +				Animal # 3 (female) +
Time after treatment	1h	24h	48h	72h	1h	24h	48h	72h	1h	24h	48h	72h
Cornea
E = degree of opacity	1	1	0	0	1	1	0	0	1	1	0	0
F = area of oapacity	2	1	0	0	4	1	0	0	3	1	0	0
Score (ExF)x5	10	5	0	0	20	5	0	0	15	5	0	0
Iris
D	1	0	0	0	1	0	0	0	1	0	0	0
Score (Dx5)	5	0	0	0	5	0	0	0	5	0	0	0
Conjunctivae
A = Redness	2	1	0	0	1	2	1	0	2	1	0	0
B = Chemosis	2	1	0	0	1	1	0	0	2	1	0	0
C = Discharge	3 RE	0	0	0	2 RE	1 RE	0	0	2 RE	0 RE	0	0
Score (A+B+C)x2	14	4	0	0	8	8	2	0	12	4	0	0
Total score	29	9	0	0	33	13	2	0	32	9	0	0

 

RE = residual test material around treated eyes

+ = one drop of ophtaine instilled into each eye 1-2 minutes prior to dosing

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Conclusions:

(1,4,5,6-Tetrahydro-4,6-dioxopyrimidin-2-yl)cyanamide produced a maximum group mean score of 31.3 and was classified as a MODERATE IRRITANT (CLASS 5 ON A 1 T0 8 SCALE) to the rabbit eye according to a modified Kay and Calandra classification system. The test material did not produce positive criteria in any rabbit according to the EEC labelling regulations and was classified as NON-IRRITANT to the rabbit eye. According to CLP (2017), the test item is not classified for eye corrosion/irritation.

Executive summary:

The study was performed to assess the irritancy potential of (1,4,5,6-Tetrahydro-4,6-dioxopyrimidin-2-yl)cyanamide following a single application to the rabbit eye according to OECD Guideline 405 (1987), also referenced as method B5 of Comission Directive 84/449/EEC. One hour after treatment iridial inflammation and moderate conjunctival irritation was noted in all treated eyes. Minimal to moderate conjunctival irritation at the 24-hour observation and minimal conjunctival irritation was noted in one treated eye at the 48-hour observation. All treated eyes appeared normal 72 hours after treatment. (1,4,5,6-Tetrahydro-4,6-dioxopyrimidin-2-yl)cyanamide produced a maximum group mean score of 31.3 and was classified as a MODERATE IRRITANT (CLASS 5 ON A 1 T0 8 SCALE) to the rabbit eye according to a modified Kay and Calandra classification system. The test material did not produce positive criteria in any rabbit according to the EEC labelling regulations and was classified as NON-IRRITANT to the rabbit eye. According to CLP (July 2017), the test item is not classified for eye corrosion/irritation.