Vandetanib (VNT) is a new oral tyrosine kinase inhibitor that acts mainly by inhibiting vascular endothelial growth factor receptor (VEGFR). Fast, specific, sensitive and validated LC–MS/MS was established for the determination of VNT in two various matrices including rat liver microsome (RLMs) and human plasma. | Liquid chromatography tandem mass spectrometry method for the quantification of vandetanib in human plasma and rat liver microsome matrices Metabolic stability investigation