Sodium methanethiolate

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:

1997

Report date:

1997

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 404 (Acute Dermal Irritation / Corrosion)

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Sodium methanethiolate

EC Number:

225-969-9

EC Name:

Sodium methanethiolate

Cas Number:

5188-07-8

Molecular formula:

CH4S.Na

IUPAC Name:

sodium methylsulfanide

Details on test material:

Test article name : Sodium methylmercaptide
CAS RN°: 5188-07-8
Origin: Elf Atochem NA
Batch: no data

Test animals

Species:

rabbit

Strain:

New Zealand White

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Myrtle's rabbitry, Thompson Station, TN, USA
- Age at study initiation: adult
- Weight at study initiation: 2.3 to 2.5 kg
- Housing: individually in suspended stainless steel cages
- Diet (ad libitum): PMI certified rabbit chow #5322
- Water (ad libitum): municipal tap water
- Acclimation period: at least 5 days

ENVIRONMENTAL CONDITIONS
- Temperature (°F): 69-71
- Humidity (%): 26-33
- Air changes (per hr): 10-15
- Photoperiod (hrs dark / hrs light): 12/12

Test system

Type of coverage:

semiocclusive

Preparation of test site:

shaved

Vehicle:

unchanged (no vehicle)

Controls:

not required

Amount / concentration applied:

Concentration: 21 % active substance

Duration of treatment / exposure:

3 minutes and 1 hour

Observation period:

1 and 24 hours

Number of animals:

6

Details on study design:

The potential irritant and/or corrosive effects of Sodium Methyl Mercaptide were evaluated on the skin of New Zealand White rabbits. Each rabbits received a 0.5 mL dose of the test article as a single dermal application. The dose was held in contact with the skin under a semi-occlusive binder for an exposure period of three minutes (6 rabbits) or 1 hour (one rabbit). Following the exposure periods, the gauze patch and/or binder were removed and the remaining test article was wiped from the skin using gauze moistened with deionized water. Test sites were evaluated for potential in-depth injury immediately following patch removal, one hour following patch removal and 24 hours following patch application.

Results and discussion

In vivo

Results

Results 1

Irritation parameter:

other: Necrosis

Basis:

other: All animals

Time point:

other: 3 min, 1 and 24 hours

Reversibility:

not reversible

Remarks on result:

other: 3-min exposure

Results 2

Irritation parameter:

other: Necrosis

Basis:

other: One animal

Time point:

other: 1 and 24 hours

Reversibility:

not reversible

Remarks on result:

other: 1-hour exposure

Irritant / corrosive response data:

Exposure to the test article for a three-minute exposure period produced necrosis (grades 1-4) and blanching (grades  3-4) on 6/6 test sites by the one hour scoring interval.  At the 24 hour scoring interval, necrosis (grades 1-2) was noted on 5/6 test sites and blanching (grades 2-4) and eschar (grades 1-3) were noted on 6/6 test sites.

Exposure to the test article for a one-hour exposure period produced necrosis (grade 4) and moderate edema on the test sites by the one hour scoring interval. In addition, the outer most layer of skin appeared to be sloughing off and this animal exhibited increased activity and labored breathing shortly after dosing. At the 24 hour scoring interval, eschar (grade 4) and severe edema were noted on the test site.

Applicant's summary and conclusion

Interpretation of results:

Category 1A (corrosive)

Remarks:

Migrated information Criteria used for interpretation of results: other: REGULATION (EC) No 1272-2008

Conclusions:

The test substance is considered to be corrosive to the skin of the rabbit after a three-minute exposure period.

Executive summary:

A primary skin irritation study using New Zealand White rabbits was performed with a 21% solution of sodium methanethiolate in water according to the OECD Test Guideline 404. Six rabbits received a 0.5 ml dose of the solution as a single dermal application under semi-occlusive conditions for 3 minutes. At one hour, necrosis (grades 1-4) and blanching (grades 3-4) were observed at all 6 sites. At 24 hours post-dose, 5/6 test sites were observed with necrosis (grades 1-2) and 6/6 test sites were blanched (grades 2-4) and had eschar (grades 1-3). Sodium methanethiolate, in a 21% aqueous solution, was determined to be corrosive, causing severe burns, to rabbit skin following a 3-minute exposure.