Phosphorothioic acid, O,O-bis(2-methylpropyl) ester, sodium salt (1:1)

Acute Toxicity: dermal

Administrative data

Endpoint:

acute toxicity: dermal

Type of information:

experimental study

Adequacy of study:

key study

Study period:

April 10, 1991 - April 25, 1991

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study with acceptable restrictions

Remarks:

Limited details on test material and environmental conditions. The observation period was limited to 7 days.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1991

Report date:

1991

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 402 (Acute Dermal Toxicity)

Deviations:

yes

Remarks:

Limited details on test material and environmental conditions. The observation period was limited to 7 days.

GLP compliance:

yes

Test type:

standard acute method

Limit test:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Sodium O,O-diisobutyl phosphorothioate

EC Number:

610-992-2

Cas Number:

53378-52-2

Molecular formula:

C8 H18 O3 P S . Na

IUPAC Name:

Sodium O,O-diisobutyl phosphorothioate

Test material form:

other: grease-like solid

Specific details on test material used for the study:

- Name of test material (as cited in study report): CT 473-91
- Name: Sodium diisobutyl monothiophoshate
- CAS: 53378-52-2
- Molecular formula: C8H18O3PS.Na
- Molecular weight: 248.26
- Substance type: Amber liquid
- Physical state: Liquid
- Lot/batch No.: SPS-17220
- Storage condition of test material: Store at room temperature in the dark

Test animals

Species:

rabbit

Strain:

New Zealand White

Sex:

male

Details on test animals or test system and environmental conditions:

- Source: Ace Animals
- Age at study initiation: Not specified
- Weight at study initiation: 2.2 - 2.5 kg
- Housing: Individually in suspended cages.
- Diet: Free access to Purina Rabbit Chow (Diet #5321)
- Water: Free access to tap water.
- Acclimation period: At least 3 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): temperature controlled
- Humidity (%): no data available
- Air changes (per hr): no data available
- Photoperiod (hrs dark / hrs light): no data available.

Administration / exposure

Type of coverage:

occlusive

Vehicle:

unchanged (no vehicle)

Details on dermal exposure:

Prior to application of the test substance, the dorsal area of each animal was clipped free of hair. The prepared site was approximately 10% of the body surface and remained intact.

The test substance was covered with a gauze patch which was secured with non-irritating adhesive tape. The torso was wrapped with plastic which was held in place with non-irritating tape.

Frequency: Single dosage, on Day 1.

Washing: No, following application, wrappings were removed and the sites were wiped.

Duration of exposure:

24 hours.

Doses:

2000 mg/kg

No. of animals per sex per dose:

5

Control animals:

no

Details on study design:

DOSAGE PREPARATION: The test substance was used as received, measured by syringe and applied to the prepared site.

Duration of observation period following administration: 7 days
- Frequency of observations and weighing:
Mortality/Viability/Clinical signs: 1, 4 and 24 hours post dose and once daily thereafter for 7 days for mortality.
Body weights: Body weights were recorded pretest and at termination.
- Necropsy of survivors performed: Not performed.
- Other examinations performed: none.

Statistics:

None.

Results and discussion

Effect levels

Sex:

male

Dose descriptor:

LD50

Effect level:

> 2 000 mg/kg bw

Based on:

test mat.

Mortality:

No mortality occurred.

Clinical signs:

other: One animal exhibited yellow nasal discharge on the day of dosing and on day 1. At all other times, all animals appeared normal during the observation period.

Gross pathology:

No data.

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Conclusions:

In an acute dermal toxicity study with CT-473-91 in rabbits, performed equivalent or similar to OECD 402 test guideline, an LD50 >2000 mg/kg bw was determined.

Executive summary:

CT-473-91, a 50% solution in water, was administered to five male New Zealand Albino rabbits by a single dermal occlusive application at 2000 mg/kg bw equivalent or similar to OECD 402 guideline and according to GLP principles.

No mortality occurred. One animal exhibited yellow nasal discharge on the day of dosing and on day 1. At all other times, all animals appeared normal during the observation period. Body weight changes were normal.

The dermal LD₅₀value of CT-473-91, a 50% solution in water, in rabbits was established to exceed 2000 mg/kg body weight.