Thioacetic acid

Skin irritation / corrosion

Administrative data

Endpoint:

skin 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:

1998

Report date:

1998

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 404 (Acute Dermal Irritation / Corrosion)

Deviations:

no

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 47956,
- purity 99.20%.

Test animals

Species:

rabbit

Strain:

New Zealand White

Details on test animals or test system 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: 3.1 ± 0.1. 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

Type of coverage:

semiocclusive

Preparation of test site:

clipped

Vehicle:

unchanged (no vehicle)

Controls:

not required

Amount / concentration applied:

0.5 ml

Duration of treatment / exposure:

3 min and 4 hours

Observation period:

up to 15 days

Number of animals:

3

Details on study design:

TEST SITE
- Area of exposure: 6 cm²
- Type of wrap if used: semi occlusive

REMOVAL OF TEST SUBSTANCE
- Washing (if done): not done

SCORING SYSTEM: Draize scale

Results and discussion

In vivo

Results

Results 1

Irritation parameter:

erythema score

Basis:

animal #1

Time point:

other: 24+48+72 h

Score:

2

Max. score:

4

Reversibility:

fully reversible within: 12 days

Results 2

Irritation parameter:

erythema score

Basis:

animal #2

Time point:

other: 24+48+72 h

Score:

1.7

Max. score:

4

Reversibility:

fully reversible within: 9 days

Results 3

Irritation parameter:

erythema score

Basis:

animal #3

Time point:

other: 24+48+72 h

Score:

1.7

Max. score:

4

Reversibility:

fully reversible within: 9 days

Results 4

Irritation parameter:

edema score

Basis:

animal #1

Time point:

other: 24+48+72 h

Score:

2

Max. score:

4

Reversibility:

fully reversible within: 6 days

Results 5

Irritation parameter:

edema score

Basis:

animal: # 2 & 3

Time point:

other: 24+48+72 h

Score:

0

Max. score:

4

Irritant / corrosive response data:

After a 3-minute exposure (one animal): No cutaneous reactions were observed during the study.
After a 4-hour exposure (three animals): A well-defined erythema was observed in all animals on day 1; it persisted up to day 11 at the latest. A slight oedema was noted in all animals from day 1 or 2; it persisted  for 24, 48 or 72 hours. Dryness of the skin was recorded in all animals  from day 5 or 6 up to day 12, 13 or 15. 

Other effects:

A slight yellow colouration of  the skin was also observed in all animals between day 1 and day 4.

Applicant's summary and conclusion

Interpretation of results:

slightly irritating

Remarks:

Migrated information not classified Criteria used for interpretation of results: EU

Conclusions:

Mean scores over 24, 48 and 72 hours for each animal were 2.0, 1.7 and 1.7 for erythema and 2.0, 0 and 0 for oedema.

Executive summary:

The potential of THIOACETIC ACID to induce skin irritation was evaluated in rabbits according to O.E.C.D. (No. 404, 17th July 1992) and E.C. (92/69/E.E.C., B₄, 31 st July 1992) guidelines. The study was conducted in compliance with the Principles of Good Laboratory Practice Regulations. The test substance was applied in a first assay for periods of 3 minutes and 4 hours to one male New Zealand White rabbit. Since the test substance was not strongly irritant in this first assay, it was applied for 4 hours to two other males in a second assay. A single dose of 0.5 ml of the test substance in its original form was applied to the closely clipped skin of one flank. The test substance was held in contact with the skin by means of a semi-occlusive dressing. Cutaneous reactions were observed approximately 1 hour, 24, 48 and 72 hours after removal of the dressing and the end of the observation period.The mean values of the scores for erythema and oedema were calculated for each animal.After a 3-minute exposure (one animal), no cutaneous reactions were observed during the study. After a 4-hour exposure (three animals), a well-defined erythema was observed in ail animals on day 1; it persisted up to day 11 at the latest.A slight oedema was noted in ail animals from day 1 or 2; it persisted for 24, 48 or 72 hours.Dryness of the skin was recorded in ail animals from day 5 or 6 up to day 12, 13 or 15. A slight yellow colouration of the skin was also observed in ail animals between day 1 and day 4. Mean scores over 24, 48 and 72 hours for each animal were 2.0, 1.7 and 1.7 for erythema and 2.0, 0 and 0 for oedema.