Fluorescence and analytical ultracentrifugation analyses of the interaction of the tyrosine kinase inhibitor, tyrphostin AG1478-mesylate, with albumin
Details
Publication Year 2005-07-15, Volume 342, Issue #2, Page 292-299
Journal Title
ANALYTICAL BIOCHEMISTRY
Publication Type
Journal Article
Abstract
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.
Publisher
ACADEMIC PRESS INC ELSEVIER SCIENCE
Keywords
HUMAN SERUM-ALBUMIN; GROWTH-FACTOR RECEPTOR; FATTY-ACID-BINDING; DRUG COMPOUNDS; CYCLODEXTRINS; PREDICTION; CHROMATOGRAPHY; COMPLEXES; DESIGN; PLASMA
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Creation Date: 2005-07-15 12:00:00
Last Modified: 0001-01-01 12:00:00
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