Development of a Bioanalytical Workflow to Support an Enhanced P-glycoprotein (P-gp) Inhibition Assay

摘要

A novel bioanalytical platform was implemented for an enhanced P-gp inhibition assay by analyzing inhibitor concentration with LC-MS/MS to calculate non-biased IC_(50) values, in addition to the SPE-MS/MS analysis of probe substrate digoxin. A bioanalytical method was developed to enable the quantitation of important P-gp inhibitor Cyclosporin A in dosing solution. The results showed that the actual concentrations of P-gp inhibitors could be significantly lower than nominal, resulting in underestimation of P-gp inhibition liabilities of test compounds; therefore it is crucial to use the determined concentrations instead of target concentrations for P-gp inhibition assessment. The platform has been successfully used to perform P-gp inhibition assessment for discovery and development compounds.