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

Acute Toxicity: inhalation

Administrative data

Endpoint:

acute toxicity: inhalation

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

7 Nov 1991 to 21 Nov 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

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 403 (Acute Inhalation Toxicity)

Version / remarks:

May 12, 1981

Deviations:

no

Test guideline 2

Qualifier:

equivalent or similar to guideline

Guideline:

EU Method B.2 (Acute Toxicity (Inhalation))

GLP compliance:

yes

Test type:

traditional 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

Results and discussion

Effect levels

Sex:

male/female

Dose descriptor:

LC50

Effect level:

> 1 800 mg/m³ air

Based on:

test mat.

Exp. duration:

4 h

Any other information on results incl. tables

No mortality was recorded during the study. Clinical signs in both sexes included piloerection, hunched posture, and dyspnea, which cleared by day 4. Body weight gain was in the expected range. Gross necropsy revealed no observable abnormalities. At autopsy, no compound-related deviations from normal morphology were seen. The acute inhalation LC50 in albino rats was determined to be greater than 1800 mg/m³.

Applicant's summary and conclusion

Interpretation of results:

study cannot be used for classification

Conclusions:

Under the conditions of the study, the acute inhalation LC50 in male and female rats was determined to be greater than 1800 mg/m³.

Executive summary:

In a GLP compliant acute inhalation toxicity study performed according to OECD guideline 403, groups of 5 male and 5 female Tif: RAI f (SPF) rats were exposed to the test material. Because of the high variability of particle size of technical material as such, it was not possible to generate an aerosol of sufficient concentration and respirable particle size. For the inhalation study the test material had to be milled twice using a jet mill adding 1 % Sipernat 50S, a highly disperse amorphic siliciumoxide. 5 male and 5 female rats (Tif:RAIf (SPF)) were exposed to milled test material for 4 hours (nose only exposure) at the maximum attainable concentration of 1800 mg/m3 air. The main exposure parameters are given in the following Table:

Nominal concentration	2767 mg/m3
Mean exposure concentration determined gravimetrically + standard deviation	1806 ± 103 mg/m3
Mass median aerodynamic diameter	1.5 - 2.9 µm
Particles < 7 μm (% w/w)	79 - 89
Air flow through generator	32 L/min
Mean chamber temperature	22.8 °C
Mean relative humidity	47 %

No mortality was recorded during the study. Clinical signs in both sexes included piloerection, hunched posture, and dyspnea, which cleared by day 4. Body weight gain was in the expected range. Gross necropsy revealed no observable abnormalities. At autopsy, no compound-related deviations from normal morphology were seen.The acute inhalation LC50 in albino rats was determined to be greater than 1800 mg/m³.