Rapid Screening of Drug-Protein Binding Using High-Performance Affinity Chromatography with Columns Containing Immobilized Human Serum Albumin

Ying-Fei Li,Wei-Yu Hu,Ping-Xia Liu,Zhen-Qing Zhang,Xiao-Qiong Zhang,Zheng Li

doi:10.1155/2013/439039

Abstract

For drug candidates, a plasma protein binding (PPB) more than 90% is more meaningful and deserves further investigation in development. In the study, a high-performance liquid chromatography method employing column containing immobilized human serum albumin (HSA) to screen in vitro PPB of leading compounds was established and successfully applied to tested compounds. Good correlation (a coefficient correlation of 0.96) was attained between the reciprocal values (X) of experimentally obtained retention time of reference compounds eluted through HSA column and the reported PPB values (Y) with a correlation equation of Y = 92.03 − 97.01X. The method was successfully applied to six test compounds, and the result was confirmed by the conventional ultrafiltration technique, and both yielded equal results. However, due to the particular protein immobilized to column, the method cannot be applied for all compounds and should be exploited judiciously based on the value of the logarithmic measure of the acid dissociation constant (pKa) as per the requirement. If α1-acid glycoprotein and other plasma proteins could be immobilized like HSA with their actual ratio in plasma to column simultaneously, the result attained using immobilized column may be more accurate, and the method could be applied to more compounds without pKa limitation.

Highlights

When entering into plasma, most compounds bind rapidly to blood constituents
Every compound binds to all the plasma proteins to a certain extent
Because albumin generally binds acidic drugs better while α1-acid glycoprotein preferentially binds to basic drugs [1, 6], pKa less than 7.0 was used as a criterion for the drug binding to human serum albumin (HSA) mainly

Summary

Introduction

Most compounds bind rapidly to blood constituents. While the phenomenon of plasma protein binding (PPB) of a chemical is considered, it usually means the protein binding of drug molecules to blood components, such as albumin and α1-acid glycoprotein [1]. The extent of protein binding in plasma is, considered one of the important physiological factors affecting pharmacokinetic characteristics, such as clearance, volume of distribution, half-life, drug-drug interaction, and the pharmacological efficacy of a drug [2,3,4,5,6]. During the lead characterization stage, protein binding is investigated in rat, dog, monkey, and human plasma. Over the past decade, with the rapid rise in new molecular entities (NMEs) arising from computational lead discovery or modification of natural products, combinatorial chemistry, and high-throughput biological screening, an urgent need has arisen for the determination of the absorption, disposition, metabolism, and excretion properties of these NMEs or even “hit” at earlier stages in the drug discovery pipeline to speed up the selection of “ideal” drug candidates for further development. Back integration of key studies into the discovery phase enables earlier identification

Methods

Results

Conclusion