Determination of the concentration of gilteritinib in human plasma using HPLC

Gilteritinib, an oral inhibitor of FMS-like tyrosine kinase 3 (FLT3), is a standard treatment for FLT3-mutated acute myeloid leukemia. We developed a simple HPLC-UV-based method for determining the concentration of gilteritinib in human plasma. The analysis requires the extraction of a 200-μL plasma sample and the precipitation of proteins by solid-phase extraction. Gilteritinib was isocratically separated within 10 min using a mobile phase of acetonitrile:0.5% monopotassium phosphate (KH₂ PO₄ , pH 3.5, 28:72, v/v) on a Capcell Pack C18 MG II (250 × 4.6 mm) column at a flow rate of 1.0 mL/min and monitored at 250 nm. The calibration curve was found to be linear within a plasma concentration range of 25-2500 ng/mL, with the coefficient of determination (r² ) being 0.9997. The coefficients of intra-day and inter-day validation were 2.3-3.7 and 1.3-5.2%, respectively. The accuracy and recovery of the assay were -9.6 to 0.1 and >81.8%, respectively. This HPLC-UV method for determining the plasma concentration of gilteritinib is simple and can be effectively applied to routine drug monitoring.