Development and clinical application of a liquid chromatography-tandem mass spectrometry-based assay to quantify eight tyrosine kinase inhibitors in human plasma

INTRODUCTION: Tyrosine kinase inhibitors (TKIs) are widely used in tumor treatment. The detection of these medicines by liquid chromatography-tandem mass spectrometry (LC-MS/MS) can avoid the interference of structurally similar compounds. OBJECTIVES: This study aimed to develop and validate a new LC-MS/MS assay for the quantification of eight tyrosine kinase inhibitors in human plasma and to preliminarily evaluate the clinical utility of the therapeutic drug monitoring method. METHODS: Plasma samples were prepared by simple protein precipitation and separated using an ultra-high-performance reversed phase column. Detection was achieved using a triple quadrupole mass spectrometer in the positive ionization mode. The assay was validated against standard guidelines. We reviewed and analyzed the results of 268 plasma samples obtained from patients administered imatinib and other TKIs collected from January 2020 to November 2021 at Zhongshan Hospital. The analytes were separated and quantified within 3.5 min. RESULTS: The newly developed method demonstrated linearity for the detected drug concentration in the range of 20 to 2000 ng/ml for gefitinib (r(2) = 0.991) and crizotinib (r(2) = 0.992), 50 to 5000 ng/ml for nilotinib (r(2) = 0.991) and imatinib (r(2) = 0.995), 1500–150,000 ng/ml for vemurafenib (r(2) = 0.998), 1000–100,000 ng/ml for pazopanib (r(2) = 0.993), 0.5–100 ng/ml for axitinib (r(2) = 0.992) and 5–500 ng/ml for sunitinib (r(2) = 0.991) and N-desethyl sunitinib (r(2) = 0.998). The lower limit of quantification (LLOQ) was 20 ng/ml for gefitinib and crizotinib, 50 ng/ml for nilotinib and imatinib, 1500 ng/ml for vemurafenib, 1000 ng/ml for pazopanib, 0.5, and 5 ng/ml for sunitinib and N-desethyl sunitinib, respectively. Specificity, precision, accuracy, and stability were tested, and met the requirements of the guidelines. At the same dose, there was no significant difference in plasma drug concentration between the original imatinib medicine and the generic medicine after patent expiration. CONCLUSION: We developed a sensitive and reliable method for the quantification of eight TKIs.