Biological fate of sirdalud in animals and man

Abstract

1. Biotransformation and excretion of the muscle relaxant drug, sirdalud, were studied after oral doses of ¹⁴C- and ³H-sirdalud in rats, dogs, rabbits, mice and humans. Sirdalud was well absorbed and almost completely metabolized in the five species.

2. Excretion of metabolites was rapid and complete within a few days; the urine/faeces excretion ratio of the ¹⁴C label was about 70/30 in all species. Major metabolic pathways of sirdalud were oxidative degradation of the imidazoline ring and oxidation of the aromatic system.

3. A novel oxidative biotransformation pathway of the benzothiadiazole ring system of sirdalud gave a sulphone analogue of the parent drug.