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Toxicological information

Eye irritation

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Administrative data

Endpoint:
eye irritation: in vivo
Type of information:
experimental study
Adequacy of study:
key study
Study period:
April 14, 2017 to May 8, 2017
Reliability:
1 (reliable without restriction)

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2017
Report Date:
2017

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
OECD Guideline 405 (Acute Eye Irritation / Corrosion)
Qualifier:
according to
Guideline:
EPA OPPTS 870.2400 (Acute Eye Irritation)
Qualifier:
according to
Guideline:
EU Method B.5 (Acute Toxicity: Eye Irritation / Corrosion)
GLP compliance:
yes

Test material

Reference
Name:
Unnamed
Type:
Constituent
Type:
impurity
Test material form:
liquid
Details on test material:
Identification (as cited in the study report): PTSA/OXA
Appearance: Clear colourless liquid
Test item storage: At room temperature protected from light
Specific details on test material used for the study:
Substance ID: PTSA/OXA
Lot#: 1092-122
Form: Liquid

Test animals / tissue source

Species:
rabbit
Strain:
New Zealand White
Details on test animals or tissues and environmental conditions:
Number of Animals: 3

Sex: Female. All animals assigned to test were nulliparous and non-pregnant.

Species/Strain: Rabbit/New Zealand albino.

Age/Body Weight: Young adult (11-12 weeks)/2190-2685 grams at experimental start.

Source: Received from Robinson Services, Inc. on AprilS and 11, 2017.

Test system

Vehicle:
unchanged (no vehicle)
Controls:
yes, concurrent no treatment
Amount / concentration applied:
0.1 mL of the test substance
Duration of treatment / exposure:
24 hr
Observation period (in vivo):
21 days
Details on study design:
A. Preparation and Selection of Animals

Prior to test initiation, both eyes of a group of animals were examined using a white light source and a fluorescein dye procedure. One drop of ophthalmic fluorescein sodium dye was instilled into both eyes of each rabbit. The eyes were rinsed with physiological saline (0.9% NaCl) after instillation of the fluorescein and then evaluated for corneal damage using an ultraviolet light source. Prior to test substance instillation, the eyes were re-examined and scored for abnormalities according to the "Scale for Scoring Ocular Lesions" (Draize et al., 1944; see Table
4). Three healthy, naive animals (not previously tested) without pre-existing ocular irritation
were selected for test.

Initially, only one rabbit was placed on test. In the absence of significant irritation in this animal, the remaining two animals were tested to confirm the result.

A systemic analgesic (Buprenorphine SR®) was administered to relieve potential discomfort associated with eye irritation which provides therapeutic relief for periods of up to 76 hours. Prior to test substance instillation, 0.1 mg/kg of body weight of the analgesic was administered to the animals and at appropriate intervals to maintain therapeutic blood levels.

B. Preparation of Test Substance

The test substance was instilled as received and mixed well prior to use.

The pH was determined for the test substance prior to the instillation and was within a pH range of 2 and 11.5, therefore testing proceeded. The procedure used and the results are retained in the raw data.

C. Instillation

Prior to instillation, 1-2 drops of ocular anesthetic (Tetracaine Hydrochloride Ophthalmic Solution USP, 0.5%) were placed into both the treated and control eye of each animal. One-tenth of a milliliter of the test substance was then instilled into the conjunctival sac of the right eye of each rabbit by pulling the lower lid away from the eyeball. The upper and lower lids were then gently held together for about one second before releasing to minimize loss of the test substance. The other eye of each rabbit remained untreated with the test substance and served as a control. The rabbits were then returned to their designated cages.

D. Ocular Scoring

Ocular irritation was evaluated using a white light source in accordance with the Draize method of scoring (Draize et al., 1944; see Table 4) at 1, 24, 48, and 72 hours and at 4, 7, 10, 14, 17 and
21 days post-instillation. At 24 hours, one drop of ophthalmic fluorescin sodium dye was
instilled into the treated eye of each rabbit, the eyes were rinsed with physiological saline (0.9% NaCI) after instillation of the fluorescein, and then evaluated for corneal damage using an ultraviolet light source. This procedure was repeated as needed at subsequent scoring intervals to evaluate the extent of corneal damage or to verifY reversal of effects. Individual scores were recorded for each animal. In addition to observations of the cornea, iris and conjunctivae, any other observed lesions were noted. The average score for all rabbits at each scoring period was calculated to aid in data interpretation.

E. Classification of Eye Scores

The time interval with the highest mean score (Maximum Mean Total Score - MMTS) for all rabbits was used to classify the test substance by the system of Kay and Calandra (Kay & Calandra, 1962).

F. Cage-5ide Observations

The animals were observed for signs of gross toxicity and behavioral changes at least once daily during the test period.

G. Body Weights

Individual weights of animals were recorded shortly before instillation of the test substance (initial) and at the completion of testing (terminal). Additional body weights were taken to determine the appropriate amount of analgesic. These additional body weights were recorded in the raw data but are not reported.

H. Study Termination

Once testing was complete, the animals were released for euthanasia and humanely euthanized.

Results and discussion

In vivo

Resultsopen allclose all
Irritation parameter:
cornea opacity score
Basis:
mean
Time point:
72 h
Score:
0
Max. score:
1
Reversibility:
fully reversible
Irritation parameter:
iris score
Basis:
mean
Time point:
24 h
Score:
0
Max. score:
0
Reversibility:
fully reversible
Irritation parameter:
conjunctivae score
Basis:
mean
Time point:
7 d
Score:
0
Max. score:
9
Reversibility:
fully reversible

Applicant's summary and conclusion

Interpretation of results:
Category 2A (irritating to eyes) based on GHS criteria
Conclusions:
Under the conditions of this study, the test substance is classified as moderately irritating to the eye. Based on the results of this study, PTSA/OXA meets the requirements for GHS Toxicity Category: Category 2B for ocular irritation.
Executive summary:

The test substance was tested for eye irritation in an in vivo OECD 405 study. The substance was instilled as is in the right eyes of three New Zealand albino rabbits. The left eyes were untreated and used as controls. Within one hour after test substance instillation, all three treated eyes exhibited 'positive' conjuctivitis. By 24 hours, corneal opacity developed in two animals. There was no iritis observed in any treated eyes. The overall incidence and severity of irritation decreases gradually with time. Positive irritation cleared from all three treated eyes by Day 4. One animal was free of ocular irritation by Day 7 and two animals were free of ocular irritation by Day 14.