High throughput screening of drug-protein binding in drug discovery

Characterization of drug-protein binding is essential, since it has profound effects on pharmacokinetic and pharmacodynamic parameters of new chemical entities. Although the traditional equilibrium dialysis method is well established and widely used for drug-protein binding measurement, this assay suffers from its low throughput. Recent efforts have been made in developing and implementing high throughput assays for drug-protein screening in drug discovery. The present review highlights high-throughput assays, as well as potential new approaches for drug-protein binding screening in drug discovery. These primarily include automated 96-well plate, sample pooling based equilibrium dialysis combined with LCMS, immobilized HSA column HPLC, and electrodriven techniques such as frontal analysis combined with capillary electrophoresis (FACE), and affinity capillary electrophoresis (ACE). Fundamental drug-protein binding models are also discussed in order to (1) compare and discriminate HSA (human serum albumin) and AGP (alpha 1-acid glycoprotein) binding with regard to the whole plasma protein binding; and (2) elucidate the applicability of high throughput screening (HTS) from the viewpoint of a simplified binding model. Some strategies and recommendations are proposed in dealing with applications of high throughput assays in different situations.