Purine-2(3H),6(1H)-dione

Eye irritation

Administrative data

Endpoint:

eye irritation: in vivo

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Justification for type of information:

The test item solubility was tested in acetonitrile, water, 1: 1 (v:v) acetonitrile:water, isopropanol, methanol, ethanol, 1,4-butandiol, N,N-dimethylformamide (DMF) and tertbutanol at 100 mM. The test item was not soluble in any of these solvents. Therefore, in vitro studies could not be performed.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2021

Report date:

2021

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

EPA OPPTS 870.2400 (Acute Eye Irritation)

Test guideline 2

Qualifier:

according to guideline

Guideline:

OECD Guideline 405 (Acute Eye Irritation / Corrosion)

Test guideline 3

Qualifier:

according to guideline

Guideline:

other: JMAFF 12-Nousan-8147

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Purine-2(3H),6(1H)-dione

EC Number:

200-718-6

EC Name:

Purine-2(3H),6(1H)-dione

Cas Number:

69-89-6

Molecular formula:

C5H4N4O2

IUPAC Name:

xanthine

Specific details on test material used for the study:

Purity: > 99%

Test animals / tissue source

Species:

rabbit

Strain:

New Zealand White

Details on test animals or tissues and environmental conditions:

TEST ANIMALS
- Source: Robinson Services Inc., Mocksville, NC
- Age at study initiation: Young adult (11-14 weeks)
- Weight at study initiation: 1940.0-2839.1 grams
- Housing: The animals were singly housed in suspended stainless steel caging which conforms to the size recommendations in the most recent Guide for the Care and Use of Laboratory Animals. Enrichment (e.g., toy) was placed in each cage. Litter paper was placed beneath the cage and was changed at least three times per week.
- Diet (e.g. ad libitum): A designated amount of the diet (approximately 150 grams/day) and alfalfa hay cubes (Grainland Select Alfalfa Cubes) were available to each rabbit
- Water (e.g. ad libitum): ad libitum
- Acclimation period: 7 or 21 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 16-23ºC; Temperature was below the targeted lower limit for four days during the study. These excursions were considered minor and had no impact on this study.
- Humidity (%): 58-95%; Humidity was above the targeted upper limit for three days during the study. A portable dehumidifier was used to lower the humidity levels during this time. These excursions were considered minor and had no impact on this study.
- Air changes (per hr): 12
- Photoperiod (hrs dark / hrs light): 12-hour light/dark cycle

Test system

Vehicle:

unchanged (no vehicle)

Remarks:

test substance was instilled as received

Controls:

yes

Amount / concentration applied:

0.1 mL (0.066 g)

Duration of treatment / exposure:

single application

Observation period (in vivo):

1, 24, 48, and 72 hours post-instillation

Number of animals or in vitro replicates:

3

Details on study design:

REMOVAL OF TEST SUBSTANCE
- Washing (if done): none

SCORING SYSTEM: Draize method of scoring at 1, 24, 48, and 72 hours post-instillation; fluorescein dye evaluation procedure used in treated eye at 24 hours to verify absence of corneal damage; individual scores recorded for each animal; in addition to observations of cornea, iris and conjunctivae, any other observed lesions were noted; average score for all rabbits at each scoring period calculated to aid in data interpretation.

TOOL USED TO ASSESS SCORE: white light source

Prior to instillation, 1-2 drops of ocular anesthetic (tetracaine hydrochloride ophthalmic solution USP, 0.5%) was placed into both treated and control eye of each animal.

Results and discussion

In vivo

Results

Results 1

Irritation parameter:

chemosis score

Basis:

animal #3

Time point:

24/48/72 h

Score:

0

Results 2

Irritation parameter:

chemosis score

Basis:

animal #2

Time point:

24/48/72 h

Score:

0.3

Reversibility:

fully reversible within: 48 hours

Results 3

Irritation parameter:

chemosis score

Basis:

animal #1

Time point:

24/48/72 h

Score:

0

Results 4

Irritation parameter:

conjunctivae score

Basis:

animal #3

Time point:

24/48/72 h

Score:

0.3

Reversibility:

fully reversible within: 48 hours

Results 5

Irritation parameter:

conjunctivae score

Basis:

animal #2

Time point:

24/48/72 h

Score:

0.3

Reversibility:

fully reversible within: 48 hours

Results 6

Irritation parameter:

conjunctivae score

Basis:

animal #1

Time point:

24/48/72 h

Score:

0

Results 7

Irritation parameter:

iris score

Basis:

animal #3

Time point:

24/48/72 h

Score:

0

Results 8

Irritation parameter:

iris score

Basis:

animal #2

Time point:

24/48/72 h

Score:

0

Results 9

Irritation parameter:

iris score

Basis:

animal #1

Time point:

24/48/72 h

Score:

0

Results 10

Irritation parameter:

cornea opacity score

Basis:

animal #3

Time point:

24/48/72 h

Score:

0

Results 11

Irritation parameter:

cornea opacity score

Basis:

animal #2

Time point:

24/48/72 h

Score:

0

Results 12

Irritation parameter:

cornea opacity score

Basis:

animal #1

Time point:

24/48/72 h

Score:

0

Irritant / corrosive response data:

No corneal opacity or iritis was observed. Conjunctival chemosis (score of one) and conjunctival redness (score of 1) were noted in two treated eyes within one hour after instillation. Irritation cleared in the treated eye of both rabbits at 48 hours.

Other effects:

All animals appeared active and healthy. Although one animal lost body weight, the two remaining animals gained body weight during the study. Apart from the eye irritation, there were no other clinical signs observed

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Conclusions:

No corneal opacity or iritis was observed from the test substance Conjunctival chemosis (score of one) and conjunctival redness (score of 1) were noted in two treated eyes within one hour after instillation. Irritation cleared in the treated eye of both rabbits at 48 hours. The test substance is not an eye irritant.

Executive summary:

A primary eye irritation test was conducted with rabbits to determine the potential of the test substance to produce irritation from a single instillation via the ocular route. One-tenth of a milliliter (0.066 grams) of the test substance was instilled into the right eye of three healthy rabbits. The left eye remained untreated and served as a control. Ocular irritation was evaluated by the Draize method of scoring. No corneal opacity or iritis was observed. Conjunctival chemosis (score of one) and conjunctival redness (score of 1) were noted in two treated eyes within one hour after instillation. Irritation cleared in the treated eye of both rabbits at 48 hours. The test substance is not an eye irritant.