Metrizoic acid

Originator

Isopaque,Winthrop,France,1973

The Uses of Metrizoic acid

Diagnosis aid (radiopaque medium).

Background

Metrizoic acid is a molecule used as a contrast medium. It present a higher risk of allergic reactions due to its high osmolality. Its approval has been discontinued by the FDA. One study in 1976 demonstrated that metrizoic acid, when used for cardiac angiography, was well tolerated. A total of 10, 000 injections were administered to 2,028 patients undergoing angiocardiographic procedures over a three-year period. With two exceptions, all complications occurred during injection of the right coronary artery. Seven cases of ventricular fibrillation, and 5 of significant bradycardia/asystole, were associated with metrizoic acid injection. In general, the drug was well tolerated by patients during cardiac examinations .

Indications

For use as a contrast medium .

What are the applications of Application

Metrizoic Acid is a diagnosis aid (radiopaque medium)

Definition

ChEBI: Metrizoic acid is a monocarboxylic acid. It has a role as a radioopaque medium.

Manufacturing Process

3,5-Diacetamido-2,4,6-triiodobenzoic acid (diatrizoic acid) (see Diatrizoate entry for synthesis) (10 g) is suspended in water (10 ml), 5 N potassium hydroxide (4.3 equivalent) is added and the mixture cooled to about 15°C. Dimethyl sulfate (0.5 equivalent) dissolved in an equal volume of acetone is added drop by drop while stirring. After the reaction mixture has been stirred for about 1 hour hydrochloric acid (1:1) is added, with stirring to pH about 0.5. The precipitate is filtered, washed and suspended moist in 4 parts of water, concentrated ammonia is added to pH about 7 and the ammonium salt solution is isomerized at 90°C to 100°C for about one-half hour whereafter additional ammonia is added to pH about 9 followed by solid ammonium chloride (about 10% weight/volume) and the solution stirred overnight and the excess of 3,5-diacetamide-2,4,6-triiodobenzoic acid recovered as ammonium salt on the filter. The filtrate is precipitated by means of hydrochloric acid (1:1 ) at pH about 0.5 and the N-methyl-3,5-diacetamido- 2,4,6-triiodobenzoic acid collected on a filter, washed and dried.

Therapeutic Function

Diagnostic aid (radiopaque medium)

Metabolism

Not Available