[Pharmacokinetics and biotransformation of oxametacine in healthy volunteers (author's transl)].

The bisphasic time-concentration course of the total plasma activity can be ascribed to 2 metabolites--oxametacine-glucuronide and desmethylindometacinamid(DMA)-glucuronide. The rate of biotransformation for oxametacine (1-p-chlorbenzoyl-2-methyl-5-methoxy-3-indolylacethydroxamic acid) is high. In contrast to laboratory animals the metabolic degradation of the mother substance to indometacine is negligible. Oxametacine is therefore not a pro-drug for indometacine in man. The main routes of biotransformation in man are: demethylation, conjugation, with active glucuronic acid, reduction to the acid amide and debenzoylation. For the 75 mg single dose urinary recoveries of the main metabolites, DMA-glucuronide and desbenzoyldesmethylmetacinamide (DBDMA)-glucuronide are 22.9% and 9.2%, respectively. The total recovery was found to be 97.55% of the dose, this being made up of 48.49% renal and 49.06% fecal excretion.