Development and Validation of a Rapid LC-MS/MS Method for Carfilzomib Quantification in Plasma from Multiple Myeloma Patients.

Carfilzomib, a second-generation proteasome inhibitor, requires therapeutic drug monitoring (TDM). This study aimed to develop and validate a sensitive and robust liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the quantification of carfilzomib in human plasma. Plasma samples were processed using protein precipitation with acetonitrile (ACN). Chromatographic separation was achieved on a C18 column (2.1 mm × 100 mm, 3.5 µm) maintained at 40 °C, with a mobile phase composed of ACN and 10 mmol/L ammonium acetate in water (80:20, v/v) delivered at a flow rate of 0.35 mL/min. The method demonstrated excellent linearity over a concentration range of 2.00-1000.00 ng/mL. In addition, high intra-day and inter-day precision and accuracy were observed, with recovery rates for carfilzomib ranging from 84.1%-93.0%. This validated LC-MS/MS method enables accurate, efficient, and sensitive determination of carfilzomib concentrations in plasma from patients with multiple myeloma, thereby supporting the optimization of carfilzomib-based therapy.