Please use this identifier to cite or link to this item: http://hdl.handle.net/1959.3/94140

Title

Fluorescence and analytical ultracentrifugation analyses of the interaction of the tyrosine kinase inhibitor, tyrphostin AG1478-mesylate, with albumin

Author(s)

Clayton, Andrew H. A.;  Perugini, Matthew A.;  Weinstock, Janet;  Rothacker, Julie;  Watson, Keith G.;  Burgess, Antony W.;  Nice, Edouard C.

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 (Kd) of 120 μM. In this article, we show that the cyclodextrin carrier molecule, Captisol, increases the apparent affinity of the hydrophobic AG1478-mesylate for albumin (Kd = 4-6 μM), 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.

Publication type

Journal article

Source

Analytical Biochemistry, Vol. 342, no. 2 (Jul 2005), pp. 292-299

Publication year

2005

FOR Code(s)

0301 Analytical Chemistry;  0601 Biochemistry and Cell Biology

Keyword(s)

AG1478;  Analytical ultracentrifugation;  Drug binding;  Fluorescence;  Tyrosine kinase inhibitor;  Tyrphostin

Publisher

Elsevier

ISSN

0003-2697

Publisher URL

http://dx.doi.org/10.1016/j.ab.2005.04.002

Copyright

Copyright © 2005 Elsevier Inc. All rights reserved.

Peer reviewed