title: Plasma protein binding of tacrolimus in humans.
abstract: An ultracentrifugation method was used for the determination of the tacrolimus (FK 506) free fraction in plasma. Samples of 400 microL were centrifuged for 6 h at 160,000 x g, and concentrations of [3H]tacrolimus were measured in the original plasma and in the second layer of the supernatant. The binding of tacrolimus in normal plasma averaged 73% and was independent of the drug concentration. Albumin (3.5%) binding averaged 44.4-57.0%, and alpha 1-acid glycoprotein (100 mg/L) binding averaged 39%. Hepatic transplant patients exhibited 72.0% +/- 3.6% binding of tacrolimus. Plasma protein binding is probably not an important factor in the disposition of tacrolimus.
authors.affiliation: Department of Pharmaceutics, School of Pharmacy, State University of New York, Buffalo 14260.
authors.forename: W
authors.initials: W
authors.lastname: Piekoszewski
authors.forename: W J
authors.initials: WJ
authors.lastname: Jusko
mesh_terms: D001798:Blood Proteins / Q000378:metabolism*; D006801:Humans; D016031:Liver Transplantation / Q000502:physiology; D008297:Male; D011485:Protein Binding; D016559:Tacrolimus / Q000097:blood*; D014461:Ultracentrifugation
chemical_list: D001798:Blood Proteins; D016559:Tacrolimus