Comparing the effect of isotopically labeled or structural analog internal standards on the performance of a LC-MS/MS method to determine ciclosporin A, everolimus, sirolimus and tacrolimus in whole blood

摘要

Background: Liquid chromatography-tandem mass spectrometry (LC-MS/MS) is routinely used for analysis of immunosuppressive drugs. This study investigated whether replacing analog internal standards (ANISs) with isotopically labeled internal standards (ILISs) has an impact on the performance of a LC-MS/MS method for the quantification of tacrolimus (TAC), sirolimus (SIR), ciclosporin A (CsA) and everolimus (EVE) in whole blood.