{Reference Type}: Journal Article {Title}: Development and validation of an ultra-performance liquid chromatography-tandem mass spectrometry method to quantify the small molecule inhibitors adagrasib, alectinib, brigatinib, capmatinib, crizotinib, lorlatinib, selpercatinib, and sotorasib in human plasma. {Author}: Hollander EM;Zimmerman NMC;Piet B;van den Heuvel MM;Burger DM;Te Brake LHM;Ter Heine R; {Journal}: Biomed Chromatogr {Volume}: 0 {Issue}: 0 {Year}: 2024 Aug 13 {Factor}: 1.911 {DOI}: 10.1002/bmc.5986 {Abstract}: Small molecule inhibitors (SMIs) are increasingly being used in the treatment of non-small cell lung cancer. To support pharmacokinetic research and clinical treatment monitoring, our aim was to develop and validate an ultra-performance liquid chromatography-mass spectrometry (UPLC-MS/MS) assay for quantification of eight SMIs: adagrasib, alectinib, brigatinib, capmatinib, crizotinib, lorlatinib, selpercatinib, and sotorasib. Development of the UPLC-MS/MS assay was done by trying different columns and eluents to optimize peak shape. The assay was validated based on guidelines of the European Medicines Agency. Chromatographic separation was performed with a gradient elution using ammonium formate in water and methanol. Detection was performed using a triple quadrupole tandem mass spectrometer with electrospray ionization. Validation was performed in a range of 10-2500 μg/L for lorlatinib, 25-6250 μg/L for alectinib and crizotinib, 25-10,000 μg/L for capmatinib and selpercatinib, 50-12,500 μg/L for brigatinib, and 100-25,000 μg/L for adagrasib and sotorasib. Imprecision was <8.88% and inaccuracy was <12.5% for all compounds. Seven out of eight compounds were stable for 96 h at room temperature. Sotorasib was stable for 8 h at room temperature. A sensitive and reliable method has been developed to quantify eight SMIs with a single assay, enhancing efficacy and safety of targeted therapies.