3,5-dimethylpyrazole

Acute Toxicity: other routes

Administrative data

Endpoint:

acute toxicity: other routes

Type of information:

experimental study

Adequacy of study:

disregarded due to major methodological deficiencies

Study period:

not reported

Reliability:

4 (not assignable)

Rationale for reliability incl. deficiencies:

other: The route of administration is non-standard for assessing acute toxicity.

Data source

Reference

Reference Type:

publication

Title:

The Diuretic Activity of 3,5-Dimethylisoxazole (DMI) and 3,5-Dimethylpyrazole (DMP) in the Rat.

Author:

Vetulani. J

Year:

1966

Bibliographic source:

Dissertationes Pharmaceuticae et Pharmacologicae Vol. 18, Pg. 19.

Materials and methods

Principles of method if other than guideline:

Litchfield-Wilcoxon (1949) in Roths Modification (1959).

GLP compliance:

no

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

3,5-dimethylpyrazole

EC Number:

200-657-5

EC Name:

3,5-dimethylpyrazole

Cas Number:

67-51-6

Molecular formula:

C5H8N2

IUPAC Name:

3,5-dimethyl-1H-pyrazole

Test material form:

not specified

Details on test material:

The test material was obtained by condensation of acetyloacetone with hydrazine hydrochloride.

Test animals

Species:

other: mice and rats

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Weight at study initiation: 15-22 g

Administration / exposure

Route of administration:

intraperitoneal

Vehicle:

polyethylene glycol

Details on exposure:

Volume of injection: 10 ml/kg. (100 mg/kg bw 3,5-dimethylpyrazole)

Doses:

single dose

No. of animals per sex per dose:

87 mice in total.

Control animals:

yes

Details on study design:

OBSERVATIONS:
Deaths were recorded after 24 hours.

Diuretic activity was examined by collected the urine of hooded or Wistar rats placed in groups of 3 in metabolic funnels. Tests were performed in normaly, overnight fasted rats (receiving water ad libitum until the start of the experiment) or in water-loaded rats. In both cases, animals were subcutaneously injected with 100 mg/kg bw, or with distilled water in volumes of 4 ml/kg. The water load was administered interperitoneally under light anesthesia at 40 ml/kg and the drugs were given simultaneously. Urine was collected after 2, 6, 9 and 24 hours from fasted rats, and 2, 4, 6 and 24 hours from water-loaded rats.

In every set of animals, one half of the groups served as controls. Because of seasonal veriations of diuresis in rats, the comparisons were done only within one group of experiments (one drug and one kind of pretreatment of the rats).

Sodium and sugar in urine concentrations were determined.

The effect of the substance on blood pressure was examined in 3 Wistar rats anesthetized with 100 mg of Sodium Amytal i.p. Blood pressure was registered from the caratoid artery with a Condon manometer, and respiration from the trachea with a marey tambour. Drugs were injected through a polyethylene cannula into the femoral vein in volume of 0.2 ml per rat.

Results and discussion

Effect levels

Sex:

not specified

Dose descriptor:

LD50

Effect level:

570 mg/kg bw

Based on:

test mat.

95% CL:

449 - 724

Remarks on result:

other: in white mice

Mortality:

A broad range of individual variation in animal mortality, often low doses caused greater mortality than the higher doses.

Clinical signs:

Motor activity stopped almost immediately when animals were dosed close to the LD50 level. Animals displayed a stupor-like response which persisted until the next day.

Other findings:

EXPERIMENTS IN RATS

Urine levels voided in the first 9 hours after injection of DMP at 100 mg/kg exceeded the normal urine output about three fold and pronounced diuresis lasted in a diminishing manner up to 24 hours.

In water loaded rats, there was no diuretic effects on DMP induced rats up to 4 hours. The level of urine excreted was increased in the 4-6 hour period, which was statistically significant. In the 6-24 hour period, the drug-treated mice produced about twice as much urine as the control rats.

3,5-dimethylpyrazone showed a short-lasting influence on blood pressure in rats. Effects were first seen at 1.8 mg/kg. In doses greater than 7.25 mg/kg, the flal in blood pressure was preceded by a very rapid and strong hypertensive effect. Atropine did not effect these reaction.
At 50 mg/kg, short lasting apnea was seen. Doses of 100 and 200 mg/kg lowered the frequency of respiratory movements.

Applicant's summary and conclusion

Conclusions:

The test material was determined to have an LD50 of 570 mg/kg bw when administered via intraperitoneal injection in white mice.

In rats, the test material was shown to have a strong diuretic effect in rats. Only a slight effect on blood pressure was observed, even at doses one half of the lethal dose. The absence of sugar in the urine excludes the possibility that the hypoglycemic action of DMP is due to lowering of the renal glucose threshold.

Executive summary:

In a non-GLP compliant study performed according to a non-standard protocol, 87 mice were exposed to the test material to assess the acute toxicity and determined the LD₅₀. Under the conditions of the test the LD₅₀was determined to be 570 mg/kg bw via intraperitoneal injection. This value cannot be used or classification purposes as the route of administration and the test model are non-standard, the mouse has been shown to be more sensitive in toxicity studies.

In rats, the test material was shown to have a strong diuretic effect in rats. Only a slight effect on blood pressure was observed, even at doses one half of the lethal dose. The absence of sugar in the urine excludes the possibility that the hypoglycemic action of DMP is due to lowering of the renal glucose threshold.