Tolazoline

Originator

Priscoline,Ciba,US,1948

The Uses of Tolazoline

Tolazoline is used for treating stable forms of pulmonary hypertension in newborns, and in cases where systemic arterial oxygenation cannot be achieved in the usual manner under careful observation of professionals.

The Uses of Tolazoline

Reactant for synthesis of imidazoline-containing drug

Background

A vasodilator that apparently has direct actions on blood vessels and also increases cardiac output. Tolazoline can interact to some degree with histamine, adrenergic, and cholinergic receptors, but the mechanisms of its therapeutic effects are not clear. It is used in treatment of persistent pulmonary hypertension of the newborn.

Indications

For the treatment of pulmonary artery anomalies

Definition

ChEBI: A member of the class of imidazoles that is 4,5-dihydro-1H-imidazole substituted by a benzyl group.

Manufacturing Process

The phenyl-acetiminoether hydrochloride of the formula from 12 parts of benzylcyanide and ethanol and HCl is mixed with 8 parts of ethylenediamine hydrate which has been diluted with little alcohol, whereby the crystals go into solution. The whole is then heated on the water-bath until the ammonia odor has disappeared, cooled, concentrated caustic potash solution added, and the separated oil extracted with ether. The solution is dried with potassium carbonate and potassium hydroxide. After evaporation a pale oil is left which distills at 147°C under a pressure of 9 mm and which solidifies in the condenser to a white crystalline mass. The yield amounts to 90% of the theory. The hydrochloride melts at 168° to 170°C.

Therapeutic Function

Vasodilator

General Description

2-Benzylimidazoline is an active vasodilator.

Pharmacokinetics

Tolazoline is a pulmonary vasodilator indicated used to decrease pulmonary vascular resistance (PVR) in persistent pulmonary hypertension of the newborn (PPHN).

Pharmacology

Tolazoline is a weak, reversible α-adrenoblocker that lowers resistance of peripheral blood vessels and elevates venous capacity. However, it also exhibits β-adrenomimetic activity, which consists of the stimulation of cardiac work and is manifest as tachycardia, cholinergic activity, which consists of stimulation of the gastrointestinal tract, and histamine-like activity, which consists of stimulation of gastric secretion.

Safety Profile

Poison by ingestion,intraperitoneal, and intravenous routes. Mutation data reported. When heated to decomposition it emits toxicfumes of NOx.

Synthesis

Tolazoline, 2-benzyl-2-imidazoline (12.2.7), is synthesized by the heterocyclation of the ethyl ester of iminophenzylacetic acid with ethylendiamine (12.2.6), which forms the desired product (12.2.7) [32¨C35]. The structure of tolazoline is strikingly similar to |á-adrenergic agonists, which are antiedema sympathomimetics.

Metabolism

Not Available