Blood partitioning
The concentration ratio of drugs in whole blood versus plasma indicates drug binding to erythrocytes. This is important when comparing clearance estimates directly with organ blood flow rates, such as in the liver, to determine the organ clearance extraction ratio. Our whole blood distribution assay determines the blood-to-plasma ratio for scaling purposes (IVIVE) and estimating hepatic first-pass extraction by converting plasma into blood clearances. These data guide the selection of the most appropriate matrix for pharmacokinetic in vivo studies. Both in vitro distribution studies can be conducted with either radiolabelled or unlabelled test compounds, using liquid scintillation counting or tandem mass spectrometry for quantification, respectively.
