1,2,4-Oxadiazole, 3-phenyl-5-(2-thienyl)-

Endpoint summary

Description of key information

The test substance was considered to be non-irritating to the rabbit skin but slightly irritating to the eyes. However, based on experience with human exposure, the test substance is considered as a skin irritant.  

Key value for chemical safety assessment

Skin irritation / corrosion

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (irritating)

Eye irritation

Link to relevant study records

Reference

Endpoint:

eye irritation: in vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

From September 7, 2011 to September 14, 2011

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: The study was conducted according to OECD Guideline 405 and OPPTS 870.2400, in compliance with GLP.

Qualifier:

according to guideline

Guideline:

OECD Guideline 405 (Acute Eye Irritation / Corrosion)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EPA OPPTS 870.2400 (Acute Eye Irritation)

Deviations:

no

GLP compliance:

yes

Species:

rabbit

Strain:

other: New Zealand albino

Details on test animals or tissues and environmental conditions:

TEST ANIMALS
- Source: Robinson Services Inc.
- Age at study initiation: Young adult
- Housing: Singly housed in suspended stainless steel caging with mesh floors. Litter paper was placed beneath the cage and was changed at least three times per week.
- Diet (e.g. ad libitum): Harlan Teklad Global High Fiber Rabbit Diet® #2031. A designated amount of the diet was available to each rabbit (approximately 150 grams/day).
- Water (e.g. ad libitum): Filtered tap water was supplied ad libitum by an automatic water dispensing system
- Acclimation period: 7 dENVIRONMENTAL CONDITIONS
- Temperature (°C): 19-22°C- Humidity (%): 68-81%The humidity was above the targeted upper limit for 5 d during the study. A portable dehumidifier was used to lower the humidity levels during this time - Air changes (per h): 12- Photoperiod (h dark / h light): 12 h light/dark cycle.

Identification
- Cage: Each cage was identified with a cage card indicating at least the study number and identification and sex of the animal.
- Animal: A number was allocated to each rabbit on receipt and a stainless steel ear tag bearing this number was attached to the animal. This number, together with a sequential animal number assigned to study 32888, constituted unique identification.

Vehicle:

unchanged (no vehicle)

Controls:

other: Other eye of each animal

Amount / concentration applied:

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): Six hundredths (0.06) grams (equivalent to a volume of 0.1 mL) of the ground test substance

Duration of treatment / exposure:

24 h

Observation period (in vivo):

1, 24, 48, and 72 h and at 4 and 7 d post-instillation

Number of animals or in vitro replicates:

3 females

Details on study design:

- Preparation and selection of animals: Healthy animals (not previously tested) without pre-existing ocular irritation were selected for test. 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 2% ophthalmic fluorescein sodium 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."

Instillation:
Prior to instillation of test substance, 2-3 drops of ocular anesthetic (tetracaine hydrochloride ophthalmic solution, 0.5%) were placed into both the treated and control eye of each animalSix hundredths (0.06) grams (equivalent to a volume of 0.1 mL) of the ground 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.

SCORING SYSTEM: Ocular irritation was evaluated using a high-intensity white light (Mag Lite) in accordance with Draize et. al. The fluorescein dye evaluation procedure described above in preparation and selection of animals section was used in the treated eye at 24 h to verify the absence of corneal damage. 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.

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. The average individually-determined irritation scores for cornea, iris and conjunctiva (redness and chemosis) across 24, 48 and 72 h were calculated for EEC classification.

TOOL USED TO ASSESS SCORE: hand-slit lamp / biomicroscope / fluorescein.
- One drop of 2% ophthalmic fluorescein sodium 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.

Irritation parameter:

cornea opacity score

Remarks:

(opacity)

Basis:

animal #1

Remarks:

(mean)

Time point:

other: 24, 48 and 72 h

Score:

0

Max. score:

4

Irritation parameter:

cornea opacity score

Remarks:

(opacity)

Basis:

animal #2

Remarks:

(mean)

Time point:

other: 24, 48 and 72 h

Score:

0

Max. score:

4

Irritation parameter:

cornea opacity score

Remarks:

(opacity)

Basis:

animal #3

Remarks:

(mean)

Time point:

other: 24, 48 and 72 h

Score:

0

Max. score:

4

Irritation parameter:

iris score

Remarks:

(lesion)

Basis:

animal #1

Remarks:

(mean)

Time point:

other: 24, 48 and 72 h

Score:

0

Max. score:

2

Irritation parameter:

iris score

Remarks:

(lesion)

Basis:

animal #2

Remarks:

(mean)

Time point:

other: 24, 48 and 72 h

Score:

0

Max. score:

2

Irritation parameter:

iris score

Remarks:

(lesion)

Basis:

animal #3

Remarks:

(mean)

Time point:

other: 24, 48 and 72 h

Score:

0

Max. score:

2

Irritation parameter:

conjunctivae score

Remarks:

(redness)

Basis:

animal #1

Remarks:

(mean)

Time point:

other: 24, 48 and 72 h

Score:

1

Max. score:

3

Irritation parameter:

conjunctivae score

Remarks:

(redness)

Basis:

animal #2

Remarks:

(mean)

Time point:

other: 24, 48 and 72 h

Score:

1

Max. score:

3

Irritation parameter:

conjunctivae score

Remarks:

(redness)

Basis:

animal #3

Remarks:

(mean)

Time point:

other: 24, 48 and 72 h

Score:

1

Max. score:

3

Irritation parameter:

chemosis score

Basis:

animal #1

Remarks:

(mean)

Time point:

other: 24, 48 and 72 h

Score:

0

Max. score:

4

Irritation parameter:

chemosis score

Basis:

animal #2

Remarks:

(mean)

Time point:

other: 24, 48 and 72 h

Score:

0

Max. score:

4

Irritation parameter:

chemosis score

Basis:

animal #3

Remarks:

(mean)

Time point:

other: 24, 48 and 72 h

Score:

0

Max. score:

4

Irritant / corrosive response data:

There was no corneal opacity or iritis observed for any treated eye during the study. Within 1 h after test substance instillation, all three treated eyes exhibited minimal conjunctivitis. The overall incidence and severity of irritation decreased gradually with time. All animals were free of ocular irritation by Day 7.

Other effects:

All animals appeared active and healthy during the study. There were no other signs of gross toxicity, adverse pharmacologic effects, or abnormal behaviour.

Interpretation of results:

not classified

Remarks:

Migrated information Criteria used for interpretation of results: EU

Conclusions:

Under the test conditions, test substance was classified as slightly irritating to the eye.

Executive summary:

A study was conducted to assess the eye irritation potential of the test substance in rabbit according to OECD Guideline 405 and OPPTS 870.2400, in compliance with GLP. A single dose of 0.1 mL test substance was applied into the sac of the right eye produced by pulling the lower eyelid, the left eye being untreated and serving as a control. Prior to instillation, 2-3 drops of ocular anesthetic (Tetracaine Hydrochloride Ophthalmic Solution, 0.5%) were placed into both the treated and control eye of each animal. Ocular irritation was evaluated in accordance with Draize scoring system at 1, 24, 48 and 72 h and at 4 and 7 d post-instillation. Both eyes of a group of animals were examined using a white light source and a fluorescein dye procedure. The average score for all rabbits at each scoring period was calculated to aid in data interpretation. The time intervals with the highest mean score (Maximum Mean Total Score - MMTS) for all rabbits were used to classify the test substance by the system of Kay and Calandra. The average individually determined irritation scores for cornea, iris and conjunctiva (redness and chemosis) were calculated for EEC classification. All animals appeared active and healthy during the study. There were no other signs of gross toxicity, adverse pharmacologic effects, or abnormal behavior. There was no corneal opacity or iritis observed for any treated eye during the study. Within 1 h after test substance instillation, all three treated eyes exhibited minimal conjunctivitis. The overall incidence and severity of irritation decreased gradually with time. All animals were free of ocular irritation by Day 7.The maximum mean total score of test substance was 4.7 at 1 h post-instillation. Under the study conditions, test substance was slightly irritating to the rabbit eye (Durando J, 2011d).

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (irritating)

Respiratory irritation

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information

Skin irritation

A study was conducted to assess the skin irritation potential of the test substance after a single topical application in rabbits according to OECD Guideline 404 and OPPTS 870.2500, in compliance with GLP. 0.77 g of the test substance moistened with distilled water was applied to a 1 inch x 1 inch, 4 ply gauze pad and placed on 6 cm²intact dose sites on three healthy rabbits. After 4 h of exposure, the test sites were gently cleansed with 3% soap solution and water. The skin reactions were assessed and recorded at approximately 30 - 60 min, 24, 48 and 72 h after patch removal. Additionally, the average erythema and oedema scores across 24, 48 and 72 h for each animal were calculated for EEC classification. All animals appeared active and healthy during the study. There were no signs of gross toxicity, adverse pharmacologic effects or abnormal behaviour. The primary dermal irritation index for test substance was 0. There was no dermal irritation observed at any treated dose site during the study. Under the conditions of this study, the test substance was considered to be non-irritating to the rabbit skin (Durando J, 2011c).

Eye irritation

A study was conducted to assess the eye irritation potential of the test substance in rabbit according to OECD Guideline 405 and OPPTS 870.2400, in compliance with GLP. A single dose of 0.1 mL test substance was applied into the sac of the right eye produced by pulling the lower eyelid, the left eye being untreated and serving as a control. Prior to instillation, 2-3 drops of ocular anesthetic (Tetracaine Hydrochloride Ophthalmic Solution, 0.5%) were placed into both the treated and control eye of each animal. Ocular irritation was evaluated in accordance with Draize scoring system at 1, 24, 48 and 72 h and at 4 and 7 d post-instillation. Both eyes of a group of animals were examined using a white light source and a fluorescein dye procedure. The average score for all rabbits at each scoring period was calculated to aid in data interpretation. The time intervals with the highest mean score (Maximum Mean Total Score - MMTS) for all rabbits were used to classify the test substance by the system of Kay and Calandra. The average individually determined irritation scores for cornea, iris and conjunctiva (redness and chemosis) were calculated for EEC classification. All animals appeared active and healthy during the study. There were no other signs of gross toxicity, adverse pharmacologic effects, or abnormal behavior. There was no corneal opacity or iritis observed for any treated eye during the study. Within 1 h after test substance instillation, all three treated eyes exhibited minimal conjunctivitis. The overall incidence and severity of irritation decreased gradually with time. All animals were free of ocular irritation by Day 7.The maximum mean total score of test substance was 4.7 at 1 h post-instillation. Under the study conditions, the test substance was slightly irritating to the rabbit eye (Durando J, 2011d).

Justification for selection of skin irritation / corrosion endpoint:
Based on experience with human exposure, the test substance needs to be classified as a skin irritant according to the CLP criteria (EC 1272/2008) as well as Directive 67/548/EEC.

Justification for selection of eye irritation endpoint:
The study followed internationally accepted guidelines and conducted in compliance with GLP.

Effects on skin irritation/corrosion: irritating

Effects on eye irritation: slightly irritating

Justification for classification or non-classification

Skin irritation:

Based on the results of an irritation study, the test substance was not considered to be irritant to skin. However, based on experience with human exposure, the test substance needs to be classified as a skin irritant according to the CLP criteria (EC 1272/2008) as well as Directive 67/548/EEC.

Eye irritation:

Based on the results of an eye irritation study, the test substance does not need to be classified for this endpoint according to the CLP criteria (EC 1272/2008) as well as Directive 67/548/EEC.