Development of an LC–MS/MS-Based Method for Quantitation of Osimertinib in Human Plasma and Cerebrospinal Fluid

Abstract

<b>Aim:</b> The transitivity of osimertinib to cerebrospinal fluid (CSF) is of clinical concern. A quantitative LC-MS/MS method for the determination of osimertinib in human plasma and CSF was developed to evaluate its transitivity. <b>Results:</b> The calibration range was 40-1000 nM in plasma and 0.8-100 nM in CSF. Accuracy and precision were within 15%. Osimertinib in the CSF but not in plasma strongly adsorbed onto the storage container. The mean adsorbed loss of osimertinib was 45.5% in CSF. Nonspecific binding in CSF was decreased by protein addition (mean loss = 5.8%). <b>Conclusion:</b> A robust validated method was developed for the quantification of osimertinib in human plasma and CSF.