Liquid chromatography-tandem mass spectrometric assay for the VEGFR inhibitor cediranib and its primary human metabolite cediranib-N⁺-glucuronide in plasma

A quantitative bioanalytical assay for cediranib and its N(+)-glucuronide metabolite was developed and validated. Human plasma samples were pre-treated using protein precipitation with acetonitrile containing erlotinib and CYT-387 as internal standards for the glucuronide metabolite and parent compound, respectively. The extract was diluted with water and injected into the chromatographic system. This system consisted of sub-2 μm particles, a trifunctional bonded octadecyl silica column with gradient elution using 0.005% (v/v) of formic acid in a mixture of water and methanol. The eluate was transferred into the electrospray interface with positive ionization and the analytes were detected in the selected reaction monitoring mode of a triple quadrupole mass spectrometer. The assay was validated in a 1-290 ng/ml calibration range for cediranib and 0.2-52 ng/ml for its glucuronide metabolite. The lowest levels of these ranges corresponded to the lower limits of quantification for both compounds. Within day precisions were 4.0-6.7% for cediranib and 4.1-11.9% for its glucuronide, between day precisions were 4.2-10.2 and 4.8-14.4% and accuracies were between 99 and 106 and 84 and 94% for cediranib and its metabolite, respectively. Stabilities of both compounds were sufficient under all relevant conditions. Finally, the assay was successfully used to assess drug levels in a pharmacokinetic mouse study.