1,3-diphenyl-2-thiourea

Eye irritation

Administrative data

Endpoint:

eye irritation: in vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

24 January 2012 - 04 February 2012

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2012

Report date:

2012

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 405 (Acute Eye Irritation / Corrosion)

Version / remarks:

2002

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

2008

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

1,3-diphenyl-2-thiourea

EC Number:

203-004-2

EC Name:

1,3-diphenyl-2-thiourea

Cas Number:

102-08-9

Molecular formula:

C13H12N2S

IUPAC Name:

1,3-diphenyl-2-thiourea

Test material form:

solid: particulate/powder

Test animals / tissue source

Species:

rabbit

Strain:

New Zealand White

Details on test animals or tissues and environmental conditions:

TEST ANIMALS
- Source: breeder: Charles River Laboratories France, l’Arbresle
- Age at study initiation: 6 months old on the day of treatment
- Mean body weight at study initiation: 3975 g (range: 3827 g to 4120 g)
- Fasting period before study: no
- Housing: noryl cages
- Diet: 110 pelleted diet (free access)
- Water: tap water filtered with a 0.22 µm filter (free access)
- Acclimation period: at least 11 days before the beginning of the study.

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 18 ± 3°C
- Humidity (%): 50 ± 20%
- Air changes (per hr): approximately 12 cycles/hour of filtered, non-recycled air
- Photoperiod (hrs dark / hrs light): 12 h/12 h (7:00 - 19:00)

IN-LIFE DATES: 25 January 2012 to 04 February 2012.

Test system

Vehicle:

unchanged (no vehicle)

Controls:

other: untreated right eye served as a control

Amount / concentration applied:

TEST MATERIAL
- Amount(s) applied: 0.1 g/animal.

Duration of treatment / exposure:

single application not followed by rinsing.

Observation period (in vivo):

1, 24, 48 and 72 h; if relevant, daily until reversibility of reactions

Number of animals or in vitro replicates:

Three females.

Details on study design:

REMOVAL OF TEST SUBSTANCE: No

SCORING SYSTEM: Draize scale.

- Conjunctival chemosis (lids and/or nictitating membranes):
0 no swelling
1 any swelling above normal (includes nictitating membranes)
2 obvious swelling with partial eversion of lids
3 swelling with lids about half-closed
4 swelling with lids more than half-closed

- Conjunctival redness (palpebral and bulbar conjunctivae, cornea and iris):
0 blood vessels normal
1 a number of blood vessels definitely hyperemic (injected)
2 diffuse, crimson colour, individual vessels not easily discernible
3 diffuse, beefy red

- Discharge:
0 absence of discharge
1 slight discharge (does not include small amounts normally found in inner canthus)
2 discharge with moistening of lids and hairs adjacent to lids
3 discharge with moistening of lids and hairs on wide area around the eye

- Iris lesions
0 normal
1 markedly deepened rugae, congestion, swelling, moderate circum-corneal hyperemia,or injection, any of these or combination of any thereof, iris still reacting to light (sluggish reaction is positive)
2 no reaction to light, haemorrhage, gross destruction (any or all of these)

- Cornea intensity of opacity (direct examination and, if necessary, with an UV lamp)
0 no ulceration or opacity
1 scattered or diffuse areas of opacity (other than slight dulling or normal lustre), details of iris clearly visible
2 easily discernible translucent area, details of iris slightly obscured
3 nacreous areas, no details of iris visible, size of pupil barely discernible
4 opaque cornea, iris not discernible through the opacity

- Cornea area of opacity (direct examination and, if necessary, with an UV lamp)
1 one quarter (or less) but not zero
2 greater than one quarter but less than a half
3 greater than one half but less than three quarters
4 greater than three quarters up to whole area

- Any other lesions observed were noted

TOOL USED TO ASSESS SCORE: UV lamp after instillation of 0.5% sodium fluorescein solution

Results and discussion

In vivo

Results

Results 1

Irritation parameter:

chemosis score

Basis:

mean

Remarks:

3 rabbits

Time point:

24/48/72 h

Score:

0.3

Max. score:

4

Reversibility:

fully reversible within: 6 days

Remarks on result:

other: Individual scores = 1 - 0 - 0

Results 2

Irritation parameter:

conjunctivae score

Remarks:

(redness)

Basis:

mean

Remarks:

3 rabbits

Time point:

24/48/72 h

Score:

1.33

Max. score:

3

Reversibility:

fully reversible within: 5 days

Remarks on result:

other: Individual scores = 1.33 - 0.3 - 0

Results 3

Irritation parameter:

iris score

Basis:

mean

Remarks:

3 rabbits

Time point:

24/48/72 h

Score:

0

Max. score:

2

Results 4

Irritation parameter:

cornea opacity score

Remarks:

(intensity)

Basis:

mean

Remarks:

3 rabbits

Time point:

24/48/72 h

Score:

0

Max. score:

4

Irritant / corrosive response data:

No ocular reactions were observed in the right untreated control eye.
In the left treated eye, a slight or moderate chemosis of the conjunctiva (grade 1 or 2) was observed in all animals on day 1, then a slight chemosis (grade 1) persisted until day 5 in animal 101.
A slight or moderate redness of the conjunctiva (grade 1 or 2) was noted in all animals on day 1, and it persisted on day 2 in animal 102 and until day 4 in animal 101.

Mean scores calculated for each animal over 24, 48 and 72 hours were as follows:
. chemosis : 1.0, 0.0 and 0.0; showing no significant eye irritation,
. redness of the conjunctiva: 1.3, 0.3 and 0.0; showing no significant eye irritation,
. iris lesions: 0.0, 0.0 and 0.0; showing no significant eye irritation,
. corneal opacity: 0.0, 0.0 and 0.0; showing no significant eye irritation

Other effects:

No unscheduled deaths occurred during the study. No clinical signs were noted in any animals.
The body weight of the animals was unaffected by the test item treatment.

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Remarks:

Not eye irritating

Conclusions:

Based on the results, the test item is not classified as irritating to the eyes according to the criteria of CLP Regulation.

Executive summary:

 

The objective of this study was to evaluate the potential irritant properties of the test item for the eye, 1,3-Diphenyl-2 -thiourea, following a single administration to rabbits.

The study was performed according to the international guidelines (OECD guideline No. 405, 24th April 2002, and Commission Regulation (EC) No. 440/2008, B.5, 30 May 2008) and in compliance with the principles of Good Laboratory Practice.

 

The test item, 1,3-Diphenyl-2-thiourea, was first administered to a single female New Zealand White rabbit.

As mean value from grading at 24, 48 and 72 hours after instillation was < 2 for conjunctival edema (chemosis) and for conjunctival redness, < 1 for iris lesion and for corneal opacity, the test item was administered in the left eye of two other animals.

 

The test item was administered inthe conjunctival sac of the left eye. The right eye remained untreated and served as control.

A quantity of 0.1 g/animal was used.

The eyes of the first animal were not rinsedjust after the 1-hour scoring, whereas, both eyes of two other animals were rinsed with a sterile isotonic saline solution (0.9% NaCl).

Each animal was observed once a day for mortality and clinical signs.Ocular reactions were observed approximately 1 hour, 24, 48 and 72 hours after the administration and then daily until the reversibility of the ocular reactions. The mean values of the scores for chemosis, redness of the conjunctiva, iris lesions and corneal opacity were calculated for each animal. Body weight was recorded on the day of treatment and the end of the observation period.

On completion of the observation period, the animals were sacrificed then discarded without macroscopic post-mortem examination.

 

A slight or moderate chemosis of the conjunctiva was observed in all animals on day 1, then a slight chemosis persisted until day 5 in 1/3 animals.

A slight or moderate redness of the conjunctiva was noted in all animals on day 1, and it persisted on day 2 in 1/3 animals and until day 4 in another animal.

 

Mean scores calculated for each animal over 24, 48 and 72 hours were as follows:

.          chemosis: 1.0, 0.0 and 0.0; showing no significant eye irritation,

.          redness of the conjunctiva: 1.3, 0.3 and 0.0; showing no significant eye irritation,

.          iris lesions: 0.0, 0.0 and 0.0; showing no significant eye irritation,

.          corneal opacity: 0.0, 0.0 and 0.0; showing no significant eye irritation.

 

In conclusion, the test item is not classified as irritating to the eyes according to the criteria of CLP Regulation.