Microsome / Hepatocyte Binding
In addition to binding to plasma proteins, compounds can also bind to microsomes and hepatocytes. Since only the free unbound fraction of the study compound can interact with metabolizing enzymes, microsome/hepatocyte binding can affect the prediction of in vivo pharmacokinetics from in vitro data.
Rapid equilibrium dialysis (RED) or ultrafiltration is used to elucidate the degree of binding of the study compound to microsomes or hepatocytes. This is followed by an analysis of the samples by LC/MS/MS.