Determination of Puquitinib in Human Plasma by HPLC-ESI MS/MS: Application to Pharmacokinetic Study

Puquitinib mesylate (XC-302) is a new multiple-target anticancer inhibitor, which directly suppresses the activity of phosphatidylinositol 3-kinase (PI3K). This study was aimed to develop a sensitive and specific liquid chromatography electrospray ionization tandem mass spectrometry (HPLC-ESI MS/MS) method for the quantification and pharmacokinetic investigation of plasma puquitinib in cancer patients.

The analytes of human plasma were prepared by liquid-liquid extraction using methyl-t-butyl ether (MTBE). The plasma analytes were separated by HPLC on Thermo ODS Hypersil column (2.1 × 150 mm; 3 μm) at 25 °C with 5 mmol/L ammonium acetate (A)-acetonitrile (B) (30:70, v/v) as the mobile phase.

The total run time was 3.5 min and the elution of puquitinib was at 1.38 min. The detection were analyzed by multiple reaction monitoring (MRM) mode with positive-ion electrospray ionization (ESI) interface using the respective [M + H]⁺ ions: m/z 318.2 → 261.1 for puquitinib and m/z 258.2 → 121.0 for the internal standard (etofesalamide). The optimized method provided a good linear relation over the concentration range of 1.00-500.00 ng/mL (r = 0.9944) for puquitinib. The intra-day and inter-day precision (relative standard deviation [RSD%]) were within 9.83%, and the intra-day and inter-day accuracy ranged from 91.05 to 103.26%. The lower limit of quantitation (LLOQ) was 1.00 ng/mL. The absolute extraction recovery was on an average of 50.43% for puquitinib and 49.3% for internal standard. In addition, the maximum plasma concentration (C_max) of puquitinib in dosage from 50 to 800 mg/m² in the human study showed an increased linearly (57.1-1289.2 ng/mL), which displayed that the concentrations had reached effective levels.

The optimized method was successfully applied to the pharmacokinetic profile study in human cancer patient plasma after the oral administration of puquitinib.