title: Competition of cytarabine and aspirin in binding to serum albumin in multidrug therapy.
abstract: The aim of this study was to describe a competition between cytarabine (araC) and aspirin (ASA) in binding with bovine serum albumin (BSA). High-affinity binding sites for both drugs were determined using a spectrofluorimetric method. Cytarabine as well as aspirin binds in the IIA hydrophobic subdomain of the transporting protein. Binding constants for araC-BSA and ASA-BSA were calculated by the Scatchard method. Analysis of ultraviolet (UV) difference spectra showed that araC, which has a higher affinity to BSA in comparison to ASA [Ka(araC) > Ka(ASA)] displaces ASA in high-affinity binding sites. The competition between drugs in low-affinity binding sites was investigated using (1)H nuclear magnetic resonance (NMR) and 13C-NMR spectra. We concluded that in the low-affinity binding sites cytarabine decreases the affinity of albumin toward aspirin. However, the interaction between araC and BSA becomes more difficult in the presence of aspirin.
authors.affiliation: Medical University of Silesia, Department of Physical Pharmacy, Jagiellońska 4, Sosnowiec, 41-200, Poland. annasulkowska@yahoo.com
authors.forename: Anna
authors.initials: A
authors.lastname: Sułkowska
authors.forename: Barbara
authors.initials: B
authors.lastname: Bojko
authors.forename: Joanna
authors.initials: J
authors.lastname: Równicka
authors.forename: Wiesław W
authors.initials: WW
authors.lastname: Sułkowski
mesh_terms: D001241:Aspirin / Q000737:chemistry* / Q000378:metabolism; D001667:Binding, Competitive; D003561:Cytarabine / Q000737:chemistry* / Q000378:metabolism; D004347:Drug Interactions; D004359:Drug Therapy, Combination; D009682:Magnetic Resonance Spectroscopy; D012710:Serum Albumin, Bovine / Q000737:chemistry* / Q000378:metabolism
chemical_list: D003561:Cytarabine; D012710:Serum Albumin, Bovine; D001241:Aspirin