Fluorescence and analytical ultracentrifugation analyses of the interaction of the tyrosine kinase inhibitor, tyrphostin AG1478-mesylate, with albumin
- Clayton, AHA; Perugini, MA; Weinstock, J; Rothacker, J; Watson, KG; Burgess, AW; Nice, EC;
Publication Year 2005-07-15, Volume 342, Issue #2, Page 292-299
- Journal Title
- ANALYTICAL BIOCHEMISTRY
- Publication Type
- Journal Article
- Quantifying the interaction of drugs with carrier proteins in plasma is of importance for understanding effective drug delivery to disease-affected tissues. In this study, we employed analytical ultracentrifugation and steady-state fluorescence spectroscopy to characterize the interaction of a potential new anticancer drug, AG1478-mesylate, with plasma proteins in a suspension of normal serum albumin (NSA). We found that mesylate salt of AG1478, an epidermal growth factor receptor kinase inhibitor, sediments in 0.1%,(w/v) NSA as a complex with a sedimentation coefficient of 3.8 S. This is consistent with the size of human serum albumin. This interaction was quantitated by meniscus depletion sedimentation and fluorescence titration analyses. AG1478-mesylate binds to albumin with an apparent single-site affinity (K-d) of 120 mu M. In this article, we show that the cyclodextrin carrier molecule, Captisol, increases the apparent affinity of the hydrophobic AG1478-mesylate for albumin (K-d = 4-6 mu M), and we propose that the AG1478-mesylate-Captisol (1: 1) complex binds to albumin with at least 10-fold higher affinity than does AG1478-mesylate ligand alone. A fluorenylmethoxycarbonyl-sulfonic acid (FMS) derivative of the 6-aminoquinazoline analog of AG1478, which was designed to have improved serum-binding properties, was shown by fluorescence analysis to bind with approximately 100-fold greater affinity than the parent compound. This has significant implications in the effective delivery of therapeutic agents in vivo. (c) 2005 Elsevier Inc. All rights reserved.
- ACADEMIC PRESS INC ELSEVIER SCIENCE
- HUMAN SERUM-ALBUMIN; GROWTH-FACTOR RECEPTOR; FATTY-ACID-BINDING; DRUG COMPOUNDS; CYCLODEXTRINS; PREDICTION; CHROMATOGRAPHY; COMPLEXES; DESIGN; PLASMA
- Publisher's Version
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Creation Date: 2005-07-15 12:00:00Last Modified: 0001-01-01 12:00:00