2,2-bis(methylthio)propane

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:

2007

Report date:

2007

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 404 (Acute Dermal Irritation / Corrosion)

Deviations:

no

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

-

EC Number:

478-900-1

EC Name:

-

Cas Number:

6156-18-9

Molecular formula:

C5 H12 S2

IUPAC Name:

2,2-bis(methylthio)propane

Details on test material:

- Name of test material (as cited in study report): BISMETHYLTHIOPROPANE
- Synonym: BMTP
- Chemical name: 2,2-bis-methylthiopropane
- Batch number: 2KS149
- Description: colorless liquid
- Storage conditions: at room temperature and protected from light
- Purity: 97.76%
- Date of analysis: 8 November 2006
- Expiry date: November 2007.

Test animals

Species:

rabbit

Strain:

New Zealand White

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Grimaud frères selection S.A.S., La Corbière, Roussay, France
- Age at study initiation: 2 to 4 months old
- Weight at study initiation: 2.9 ± 0.2 kg
- Housing: individually in Pajon cages (50 cm x 57 cm x 75 cm)
- Diet: free access to 110C pelleted diet (SAFE, Villemoisson, Epinay sur-Orge, France)
- Water: Drinking water filtered by a FG Millipore membrane (0.22 micron) was provided 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): 12/12

IN-LIFE DATES: From 23 January 2007 to 08 February 2007

Test system

Type of coverage:

semiocclusive

Preparation of test site:

other: clipped

Vehicle:

unchanged (no vehicle)

Controls:

not required

Amount / concentration applied:

500 mg

Duration of treatment / exposure:

3 minutes, 1 hour and 4 hours

Observation period:

1 hour, 24, 48 and 72 hours, then daily up to 15 days

Number of animals:

3

Details on study design:

TEST SITE
The test item was first evaluated on a single animal (No. 782). The durations of exposure were 3 minutes, 1 hour and 4 hours.
Since the test item was neither severely irritant nor corrosive on this first animal, it was then applied simultaneously for 4 hours to two other animals (Nos. 799 and 800). Doses of 0.5 mL of the undiluted test item were placed on a dry gauze pad, which was then applied to an area of approximately 6 cm2 of the anterior left flank (application for 3 minutes), the anterior right flank (application for 1 hour) or the posterior right flank (application for 4 hours) of the animals.
The gauze pad was held in contact with the skin by means of an adhesive hypoallergenic aerated semi-occlusive dressing and a restraining bandage.
The untreated skin served as control.
No residual test item was observed on removal of the dressing.

REMOVAL OF TEST SUBSTANCE
- Washing (if done): no

SCORING SYSTEM:
Kay and Calandra scale

Results and discussion

In vivo

Results

Results 1

Irritation parameter:

erythema score

Basis:

animal #1

Time point:

24/48/72 h

Score:

1

Max. score:

4

Reversibility:

fully reversible within: 4 days

Results 2

Irritation parameter:

erythema score

Basis:

animal #2

Time point:

24/48/72 h

Score:

2

Max. score:

4

Reversibility:

not fully reversible within: 15 days

Results 3

Irritation parameter:

erythema score

Basis:

animal #3

Time point:

24/48/72 h

Score:

1.3

Max. score:

4

Reversibility:

fully reversible within: 6 days

Results 4

Irritation parameter:

edema score

Basis:

animal: #1, 2 & 3

Time point:

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.

After a 1-hour exposure (one animal)
A very slight erythema (grade 1) was noted from day 1 until day 4.

After a 4-hour exposure (three animals)
A very slight to moderate erythema (grade 1 to 3) was noted in all animals from day 1 until day 3, 5 or 15 (end of the observation period).
A dryness of the skin was recorded in 2/3 animals from day 4 until day 10 or 15.

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Conclusions:

BISMETHYLTHIOPROPANE was slightly irritant when applied topically to rabbits.

Executive summary:

The potential of BISMETHYLTHIOPROPANE (BMTP) to induce skin irritation was evaluated in rabbits according to OECD guideline 404. The study was conducted in compliance with the principles of Good Laboratory Practice Regulations. BMTP was first applied for periods of 3 minutes, 1 hour and 4 hours to a single male New Zealand White rabbit. Since BMTP was neither severely irritant nor corrosive on this first animal, it was then applied simultaneously for 4 hours to two other animals. A single dose of 0.5 mL of the undiluted BMTP was applied to the closely-clipped skin of one flank. BMTP 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 then daily for 15 days. The mean values of the scores for erythema and edema were calculated for each animal.

After a 3-minute exposure (one animal), no cutaneous reactions were observed. After a 1-hour exposure (one animal), a very slight erythema was noted from day 1 until day 4. After a 4-hour exposure (three animals), a very slight to moderate erythema was noted in all animals from day 1 until day 3, 5 or 15 (end of the observation period). A dryness of the skin was recorded in 2/3 animals from day 4 until day 10 or 15. Mean scores over 24, 48 and 72 hours for each animal were 1.0, 2.0 and 1.3 for erythema and 0.0, 0.0 and 0.0 for edema. BISMETHYLTHIOPROPANE was slightly irritant when applied topically to rabbits.