Serum Shift Assays

Testing the effect of investigational new drugs on ion channels in vitro  are well established procedures in preclinical development and provide the basis for risk assessment. If assays are conducted under artificial conditions they tend to neglect the physiological presence of proteins. However, the majority of test compounds bind to plasma proteins often resulting in a reduction of the in vivo free effective concentration by more than 90%.

To simulate a more physiological situation, we assessed if ion channel assays using the patch-clamp technique can be performed in the presence of human plasma.

To investigate the effect of plasma binding of test compounds on the IC₅₀ value for two compounds the dose response curve was determined in presence of standard bath solution and in the presence of human plasma.