Hydrophilic interaction liquid chromatography/positive ion electrospray mass spectrometry for the quantification of deferasirox, an oral iron chelator, in human plasma

A rapid hydrophilic interaction liquid chromatography/positive ion electrospray mass spectrometric assay (HILIC/ESI-MS) was developed, validated and applied to the determination of deferasirox, in human plasma. The sample preparation process involved liquid–liquid extraction of 50 μL plasma sample using ethyl acetate as an extraction solvent. Chromatographic separation was performed on an XBridge®-HILIC analytical column (150.0 mm × 2.1 mm i.d., particle size 3.5 μm, 135 Å) under isocratic elution. The mobile phase was composed of a 10% 8.0 mM ammonium acetate water solution pH = 5.0, adjusted with formic acid, in a binary mixture of acetonitrile/methanol (50:50, v/v) and pumped at a flow rate of 0.20 mL/min. Quantitation of deferasirox was performed with selected ion monitoring (SIM) in positive ionization mode using electrospray ionization interface. The assay was found to be linear in the concentration range of 0.20–120.0 μg/mL for deferasirox. Intermediate precision was found less than 3.9% over the tested concentration ranges. A run time of less than 6.0 min for each sample made it possible to analyze a large number of human plasma samples per day. The method can be used to support a wide range of clinical studies concerning deferasirox monitoring and it was applied to the analysis of human plasma samples obtained from patients with β-thalassemia major.