Abstract
Isbufylline metabolism after oral administration to humans was studied. The main metabolites detected by the HPLC method, in plasma, were 1-methyl-7-(2-hydroxy-2-methyl-propyl) xanthine (I), 1,3-dimethyl-7-(2-hydroxy-2-methyl-propyl) xanthine (II), and 1-methyl-7-(2-methyl-propyl) xanthine (III). The main metabolites detected in urine were 1-methyl-7-(2-hydroxy-2-methyl-propyl) xanthine (I), 1,3-dimethyl-7-(2-carboxy-propyl) xanthine (IV), and 1,3-dimethyl-7-(2-hydroxymethyl-propyl) xanthine glucuronic acid (V)-Gluc. They were isolated by HPLC, identified by GC/MS, HPLC/MS, or HPLC/MS/MS, and finally synthesized. Recovery of these metabolites, along with the absence of unmetabolized isbufylline in the urine, indicated biotransformation and renal excretion as the main routes of isbufylline elimination in humans. HPLC quantitation of the characterized urine metabolites revealed that 49% of the drug was eliminated as (I), 9% as (V)-Gluc, and 5% as (IV).
DMD articles become freely available 12 months after publication, and remain freely available for 5 years.Non-open access articles that fall outside this five year window are available only to institutional subscribers and current ASPET members, or through the article purchase feature at the bottom of the page.
|