RT Journal Article SR Electronic T1 PHYSIOLOGICAL DISPOSITION OF FENOPROFEN IN MAN. III. METABOLISM AND PROTEIN BINDING OF FENOPROFEN JF Journal of Pharmacology and Experimental Therapeutics JO J Pharmacol Exp Ther FD American Society for Pharmacology and Experimental Therapeutics SP 449 OP 457 VO 183 IS 2 A1 ALAN RUBIN A1 PATRICIA WARRICK A1 ROBERT L. WOLEN A1 STANLEY M. CHERNISH A1 ANTHONY S. RIDOLFO A1 CHARLES M. GRUBEIL, JR. YR 1972 UL http://jpet.aspetjournals.org/content/183/2/449.abstract AB We have conducted studies of the metabolism and protein binding of fenoprofen. dl-2-(3-phenoxyphenyl) propionic acid, in man. Urinary metabolites (as perecntage of administered dose) were: fenoprofen glucuronide (45%), 4'-hydroxyfenoprofen glucuronide (45%), 4'-hydroxyfenoprofen (2-5%) and unchanged fenoprofen (2-5%). Also excreted were an acid-labile conjugate of fenoprofen (2-5%), which does not appear to be a glycine or glutamine conjugate, and an acid-labile conjugate of 4'-hydroxyfenoprofen (2-5%), which does not appear to be a sulfate conjugate. Fenoprofen binding to protein was studied by dialysis and ultracentrifugation techniques. The compound was extensively and strongly bound to plasma albumin. Other drugs which are themselves protein bound were studied to learn whether they might displace fenoprofen from protein binding sites. When dialysis conditions were set to favor displacement, only phenylbutazone reduced fenoprofen binding; d-propoxyphene, indomethacin and aspirin had no such effect. In ultracentrifugation experiments, warfarin did not reduce fenoprofen binding over a wide range of warfarin concentrations; fenoprofen slightly reduced warfarin binding (94 to 91% bound) at fenoprofen concentrations considerably higer than expected for prolonged periods in vivo. © 1972 by The Williams & Wilkins Co.