Practical approaches to incurred sample LC-MS/MS reanalysis: confirming unexpected results.
Incurred sample reanalysis (ISR) is an important step in assuring the quality of an LC-MS/MS bioanalytical assay and the integrity of bioanalysis conduct. A conventional ISR involves analysis of at least 20 samples taken from an in vivo study a second time using the method that was described in prestudy validation and employed in generating the initial study sample results. However, this practice is sometimes inadequate to confirm bioanalytical results that are unexpected. The present report discusses several additional exploratory activities that were performed to confirm the unexpected plasma concentration-time results of NVP-1, an investigational drug candidate, observed in the plasma samples collected from patients in a phase II trial. These approaches include (1) LC-MS/MS reanalysis of the study samples after multiple freeze/thaw cycles followed by a short-term benchtop storage, (2) evaluation of additional MS/MS transitions in LC-MS/MS, (3) employment of a different sample preparation procedure in LC-MS/MS, and (4) study sample dilution using plasma samples from healthy volunteers. These procedures are practical and can be readily implemented in the confirmatory LC-MS/MS bioanalysis of other small molecules.
Department of Drug Metabolism and Pharmacokinetics, Novartis Institutes for BioMedical Research, One Health Plaza, East Hanover, New Jersey 07936, United States. wenkui.li@novartis.com
Wenkui
W
Li
Hui
H
Lin
Jimmy
J
Flarakos
Francis L S
FL
Tse
D002247:Carbon Isotopes / Q000737:chemistry; D002851:Chromatography, High Pressure Liquid; D002986:Clinical Trials as Topic; D004791:Enzyme Inhibitors / Q000097:blood* / Q000302:isolation & purification; D006801:Humans; D007553:Isotope Labeling; D059625:Liquid-Liquid Extraction; D053719:Tandem Mass Spectrometry
D002247:Carbon Isotopes; D004791:Enzyme Inhibitors