pymetrozine (ISO); (E)-4,5-dihydro-6-methyl-4-(3-pyridylmethyleneamino)-1,2,4-triazin-3(2H)-one

Acute Toxicity: dermal

Administrative data

Endpoint:

acute toxicity: dermal

Type of information:

experimental study

Adequacy of study:

key study

Study period:

23 Jul 1991 to 6 Aug 1991

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1991

Report date:

1991

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

EPA OPP 81-2 (Acute Dermal Toxicity)

Deviations:

no

GLP compliance:

yes

Test type:

standard acute method

Limit test:

yes

Test material

Test material information

Constituent 1

Reference substance name:

6-methyl-4-[(E)-[(pyridin-3-yl)methylidene]amino]-2,3,4,5-tetrahydro-1,2,4-triazin-3-one

EC Number:

602-927-1

Cas Number:

123312-89-0

Molecular formula:

C10H11N5O

IUPAC Name:

6-methyl-4-[(E)-[(pyridin-3-yl)methylidene]amino]-2,3,4,5-tetrahydro-1,2,4-triazin-3-one

Test material form:

solid: particulate/powder

Test animals

Species:

rat

Strain:

Sprague-Dawley

Remarks:

Hsd:Sprague Dawley SD

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Weight at study initiation: 250 to 286 g (for males), 220 to 244 g (for females)
- Housing: individually housed in screen-bottom, stainless steel cages.
- Diet: a measured amount of Rodent Chow® #5001
- Water: ad libitum
- Acclimation period: at least 7 days

ENVIRONMENTAL CONDITIONS
Animal husbandry and housing comply with standards outlined in the "Guide for the Care and Use of Laboratory Animals" (NIH publication number No. 86-23, revised 1985). Variations from the prescribed environmental conditions existed and were considered to have had no effect on the study outcome. No contaminants were expected to have been present in the feed or water which would have interfered with or affected the results of the study.

- Temperature (°C): 19 to 25
- Humidity (%): 52 to 69

IN-LIFE DATES:
23 July 1991 to 6 August 1991

Administration / exposure

Type of coverage:

occlusive

Vehicle:

physiological saline

Details on dermal exposure:

TEST SITE
- Area of exposure: back of the rat
- % coverage: at least 10%
- Type of wrap if used: The area of application was covered with a 5.0 cm x 5.0 cm gauze patch secured with paper tape, and overwrapped with Saran Wrap and Elastoplast tape.

REMOVAL OF TEST SUBSTANCE
- Washing: washed using tap water and disposable paper towels
- Time after start of exposure: at the end of the 24-hour exposure period

Duration of exposure:

24 hours

Doses:

2.0 g/kg bw

No. of animals per sex per dose:

5

Control animals:

no

Details on study design:

- Duration of observation period following administration: 14 days
- Frequency of observations and weighing: Clinical signs and mortality checks were conducted at approximately 1, 2.5, and 4 hours after test material administration. The animals were observed daily thereafter for 14 days for clinical signs and dermal irritation and twice a day (morning and afternoon) for mortality. Body weights were determined before test material application (Day 0), at Day 7, and at termination of the experimental phase (Day 14).
- Necropsy of survivors performed: yes

Statistics:

No statistical analyses were required by the protocol.

Results and discussion

Effect levels

Key result

Sex:

male/female

Dose descriptor:

LD50

Effect level:

> 2 000 mg/kg bw

Based on:

test mat.

Remarks on result:

no indication of skin irritation up to the relevant limit dose level

Mortality:

No mortality observed

Clinical signs:

other: All animals appeared clinically normal and exhibited no dermal irritation throughout the study

Gross pathology:

No deviations from normal morphology were found

Applicant's summary and conclusion

Interpretation of results:

other: Not classified according to CLP

Conclusions:

In this GLP compliant US EPA 81-2 study in Sprague-Dawley rats, the LD50 was determined to be > 2000 mg/kg body weight for males/females.

Executive summary:

In this GLP compliant US EPA 81-2 study, the acute dermal toxicity of the test substance was evaluated in male and female Sprague-Dawley rats (5 animals per sex). The moistened test substance was administered as a single topical application under occlusive conditions at a level of 2000 mg/kg of body weight. After 24 hours of exposure, the test substance was washed using tap water and disposable paper towels. Clinical signs, body weight and mortality were recorded for 14 days after the end of the treatment. All animals were clinically normal and exhibited no dermal irritation throughout the study. Body weights were unaffected and no deviations from normal morphology were found. No animals died during the study. The estimated dermal LD50 was determined to be greater than 2000 mg/kg bw.