The localization, distribution and elimination of l4C_Tienilic acid, a new diuretic and hypouricemic drug has been described.This study was carried out using l4C labelled compound on four different animal species: mice, rats, pigs and dogs. The blood level is expressed as f.1g/ml equivalents of the administered product. After oral administration, the absorption rate of this product in doses of 5 mg/kg for rats, pigs and dogs was between 50 and 80 %, depending on the species.Tienilic acid was rapidly distributed in most of the essential organs and tissues with the exception of the brain. In the blood the product was found only at the plasmatic level with high plasmatic protein binding, around 72-95 %.Biliary and particularly urinary elimination was fast and practically complete in 48 hours.

The metabolic fate of a new diuretic, tienilic acid, was investigated in Wistar rats, Swiss mice, Beagle dogs, and large white pigs using the 14C-labelled compound. Tienilic acid and its metabolites were determined in bile, urine, and plasma following intravenous and oral administration. In general, only a small amount of unmetabolized drug is excreted. Biotransformation consists of two major metabolic routes; one is reduction and the other is oxidative hydrolysis of the molecule at the level of the carbonyl group. These two routes co-exist in all species studied, but the reduction route is prominent in the dog. Mass spectrometry was used to elucidate the structure of two metabolites and confirm it for the third.

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