butyl methylphosphinate

Acute Toxicity: oral

Administrative data

Endpoint:

acute toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1990

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1990

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 401 (Acute Oral Toxicity)

GLP compliance:

yes

Test type:

acute toxic class method

Limit test:

yes

Test material

Reference

Name:

Unnamed

Type:

Constituent

Test animals

Species:

rat

Strain:

Wistar

Sex:

male/female

Details on test animals or test system and environmental conditions:

Body weight at start of study: males 209 g (minimum 204 g, maximum 212 g), females 167 g (minimum 141 g, maximum 178 g)
Age at start of study: males approx. 7 weeks, females approx. 8 weeks
in fully air-conditioned rooms in Makrolon cages (Type 4) on soft wood granulate in groups of 5 animals

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

water

Doses:

2000 mg/kg body weight

No. of animals per sex per dose:

5 male / 5 female

Control animals:

no

Details on study design:

The prepared test substance was administered by gavage to fasted animals at the stated dosage level. The observation period following treatment lasted 15 days. A record was kept of the times at which signs of intoxication emerged and of the times of death. During this time the animals were weighed weekly. The animals found dead during the study were dissected and autopsied. At the end of the observation period the surviving animals were killed by carbon dioxide asphyxiation, dissected and also examined for macroscopically visible changes.

Results and discussion

Effect levels

Sex:

male/female

Dose descriptor:

LD50

Effect level:

> 2 000 mg/kg bw

Mortality:

During the observation period, no mortality occurred among the females after treatment with 2000 mg/kg body weight. One male died during the 2nd night after treatment.
Based on the results of the present study, the median lethal dose (LD50) for the male and female Wistar rat is with certainty greater than 2000 mg/kg body weight.

Clinical signs:

The clinical signs of intoxication were rather the same for males and females, but more pronounced in the females. They were marked only on the day of treatment. The clinical signs such as contracted flanks, squatting position, irregular respiration, decreased spontaneous activity, ataxic or stilted gait and piloerection were observed in most animals. The other clinical signs (uncoordinated gait, crawling locomotion, prone position, poor general condition, reduced paw-pinch reflex and placing reflex, no cornea! reflex, stupor, narrowed palpebral fissures, dilated (mydriasis) or contracted (miosis) pupils, panting and increased sound production) occurred to a smaller extent.

Body weight:

There were no impairments of body weight gains.

Gross pathology:

Macroscopic examination of the male found dead during the study revealed the following abnormalities:
- stomach filled with gas
- lungs discoloured orange.
The remaining animals killed at the end of the observation period were free of macroscopically visible changes.

Applicant's summary and conclusion

Interpretation of results:

practically nontoxic

Remarks:

Migrated information Criteria used for interpretation of results: EU

Conclusions:

Based on the mortality rate obtained in this study, the median lethal dose (LD50) for the male and female Wistar rat is with certainty greater than 2000 mg/kg body weight.
According to the criteria defined in the Directive 83/467/EEC butyl methylphosphinate is not subject to labelling requirements.

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