Ficoll paque plus solution

TAC, MPA, and mycophenolic acid-d3 (MPA-d3) which is a deuterated product of mycophenolic acid, were purchased from Toronto Research Chemicals (Toronto, ON, Canada), and [¹³C, ²H₄]-tacrolimus was purchased from Alsachim (Strasbourg, France). Methanol, acetonitrile, and formic acid were obtained from Fisher Chemical (Thermo Scientific, Waltham, MA, USA) at ultra-high performance liquid chromatography/mass spectrometry grades. Ammonium acetate was obtained from Sigma-Aldrich (St. Louis, MO, USA). Ultra-pure water was supplied by the Milli-Q integral water purification system (Merck Millipore, Germany). MagSiMUS-TDM^prep Type I Particle Mix, Organic Precipitation Reagent VI (OPR VI), and Lysis Buffer for whole blood kits were purchased from MagnaMedics Diagnostics B.V. (Geleen, The Netherlands). Ficoll-Paque Plus solution, Dulbecco’s phosphate-buffered saline (D-PBS) without calcium and magnesium ions, and red blood cell lysis buffer were obtained from Solarbio (Beijing, China). PBMCs for the establishment and validation of analytical methods were obtained from healthy volunteers in agreement with the local ethics committee.