title: Pharmacokinetics and biotransformation studies of terfenadine in man.
abstract: Comparison of plasma level data obtained from a dose-response study to that of a 14C material balance study indicates that 99.48% of the alpha-[4-(1,1-dimethylethyl)phenyl] 4-(hydroxydiphenylmethyl)-1-piperidinebutanol (terfenadine, RMI 9918, Triludan, Teldane, resp.) related material absorbed undergoes biotransformation. From the balance study it has been determined that fecal excretion accounts for ca. 60% of the dose administered. Thin-layer chromatographic analysis of urine and feces revealed the presence of two major metabolic products. These compounds have been isolated and their structures determined by GC-MS. One of the metabolic products, a carboxylic acid analog of terfenadine has been shown to have antihistaminic activity and may play a role in the activity of the parent drug in vivo.
mesh_terms: D001559:Benzhydryl Compounds / Q000378:metabolism*; D001682:Biological Availability; D001711:Biotransformation; D004305:Dose-Response Relationship, Drug; D005243:Feces / Q000032:analysis; D008401:Gas Chromatography-Mass Spectrometry; D006801:Humans; D007700:Kinetics; D008297:Male; D011863:Radioimmunoassay; D016593:Terfenadine
chemical_list: D001559:Benzhydryl Compounds; D016593:Terfenadine