Thioacetic acid

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:

other: GLP guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1999

Report date:

1999

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 405 (Acute Eye Irritation / Corrosion)

Deviations:

yes

Remarks:

Since the test substance showed severe irritant properties in the first rabbit, the study was considered complete and the test substance was not evaluated in other animals.

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

Thioacetic acid

EC Number:

208-063-8

EC Name:

Thioacetic acid

Cas Number:

507-09-5

Molecular formula:

C2H4OS

IUPAC Name:

ethanethioic S-acid

Test material form:

other: liquid

Details on test material:

- Name of test material (as cited in study report): Thioacetic acid
- batch AOGHJU
- purity 99.58%.

Test animals / tissue source

Species:

rabbit

Strain:

New Zealand White

Details on test animals or tissues and environmental conditions:

TEST ANIMALS
- Source: Elevage Cunicole de Val de Selle, 80160 Prouzel, France.
- Age at study initiation: no data
- Weight at study initiation: 2.6 kg
- Housing: housed individually in polystyrene cages
- Diet: 112 C pelleted diet, ad libitum
- Water: filtered by a F.G. Miilipore membrane (0.22 micron) ad libitum
- Acclimation period: at least 5 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 18 ± 3
- Humidity (%): 30 to 70
- Air changes (per hr): 12
- Photoperiod (hrs dark / hrs light): 12 h/12 h

Test system

Vehicle:

unchanged (no vehicle)

Controls:

not required

Amount / concentration applied:

Amount applied: 0.1 ml

Duration of treatment / exposure:

Not rinsed

Observation period (in vivo):

up to 72 hours

Number of animals or in vitro replicates:

1

Details on study design:

As possible irritant effects were anticipated, a first assay was  conducted in one male New Zealand White rabbit. Since the test substance showed severe irritant properties in this first assay, the study was considered complete and the test substance was not evaluated in other animals. A single dose of 0.1 ml of the undiluted test substance was instilled into the left conjunctival sac. The right eye served as control. The eyes were not rinsed after administration of the test substance. Ocular reactions were observed approximately 1 hour, 24, 48 and 72 hours after the administration. The mean values of the scores for chemosis and corneal opacity were calculated.

Results and discussion

In vivo

Results

Results 1

Irritation parameter:

cornea opacity score

Basis:

animal #1

Time point:

other: 24+48+72 h

Score:

3

Max. score:

4

Reversibility:

not reversible

Remarks:

after 3 days

Results 2

Irritation parameter:

chemosis score

Basis:

animal #1

Time point:

other: 24+48+72 h

Score:

3

Max. score:

4

Reversibility:

not reversible

Remarks:

after 3 days

Results 3

Irritation parameter:

iris score

Basis:

animal #1

Remarks on result:

other: the scoring of iritis was masked by this important corneal opacity

Results 4

Irritation parameter:

conjunctivae score

Basis:

animal #1

Remarks on result:

other: Scoring masked by a whitish colouration of the conjunctivae

Irritant / corrosive response data:

Slight or moderate conjunctival reactions (slight or moderate chemosis, whitish coloration of the conjunctivae and clear to whitish purulent discharge) were observed between day 1 and day 4. A moderate corneal opacity was recorded between day 1 and day 4; the scoring of iritis was masked by this important corneal opacity. In the view of these ocular reactions, the animal was killed on day 4 for ethical reasons. Mean scores calculated over 24, 48 and 72 hours were 3.0 for chemosis and  3.0 for corneal opacity. Other scores were not calculable.

Applicant's summary and conclusion

Interpretation of results:

Category 1 (irreversible effects on the eye)

Remarks:

Migrated information Criteria used for interpretation of results: EU

Conclusions:

THIOACETIC ACID is severely irritant when administered by ocular route to rabbits.

Executive summary:

The potential of THIOACETIC ACID to induce ocular irritation was evaluatedin rabbits according to OECD (No. 405, 24th February 1987) and EC (92/69/EEC, B.5, 31 st July1992) guidelines. The study was conducted in compliance with the principles of Good Laboratory Practice Regulations. As possible irritant effects were anticipated, a first assay was conducted in one male New Zealand White rabbit. Since the test substance showed severe irritant properties in this first assay, the study was considered complete and the test substance was not evaluated in other animals. A single dose of 0.1 ml of the undiluted test substance was instilled into the left conjunctival sac. The right eye served as control. The eyes were not rinsed after administration of the test substance. Ocular reactions were observed approximately 1 hour, 24, 48 and 72 hours after the administration. The mean values of the scores for chemosis and corneal opacity were calculated. Slight or moderate conjunctival reactions (slight or moderate chemosis, whitish coloration of the conjunctivae and clear to whitish purulent discharge) were observed between day 1 and day 4. A moderate corneal opacity was recorded between day 1 and day 4; the scoring of iritis was masked by this important corneal opacity. In the view of these ocular reactions, the animal was killed on day 4 for ethical reasons. Mean scores calculated over 24, 48 and 72 hours were 3.0 for chemosis and 3.0 for corneal opacity. Other scores were not calculable. THIOACETIC ACID is severely irritant when administered by ocular route to rabbits.