Applicable pharmacokinetic study: Development and validation of bioanalytical LC-MS/MS method for the simultaneous quantification of cytarabine and glasdegib used for the treatment of acute myeloid leukemia

Abstract

Acute myeloid leukemia (AML) is characteristic by high concentrations of immature bone marrow myeloid cells. Glasdegib (DaurismoTM, GSB) in combination with low dose cytarabin (DepocytTM, CTB) have recently been approved by the US Food and Drug Administration for the treatment of newly diagnosed AML in patients over 75 years of age or who have comorbidities that are prohibitive to intensive induction chemotherapy. However, the pharmacokinetic characteristics of the CTB and GSB is yet unknown. This study developed a selective, sensitive and fast analytical method using liquid chromatography-electrospray ionization (ESI) with tandem mass spectrometry (LC-MS/MS) to simultaneously quantify of CTB and GSB in rat plasma using duvelisib as internal standard (IS). The LC-MS/MS instrument was performed in the ESI interface operating at positive ionization and multiple reaction monitoring (MRM) mode. The CTB and GSB with the IS were extracted from rat plasma by using cation exchange solid-phase extraction cartridge before the analysis. The cartridge gave high recovery rates for both drugs without interference from plasma endogenous. Chromatographic separation was performed on reversed-phase polar-100 column (100 mm × 2.1 mm, 3 µm), with an isocratic mobile phase consisted of a mixture of water containing 0.1% formic acid and acetonitrile (85:15, v/v, pH 3.2) at a flow rate of 0.4 mL/min and the process of analysis was run for 3.5 min. The developed method was validated as per the FDA guidelines over a linear concentration range of 5–3000, for both CTB and GSB with high correlation coefficient (r2 ≥ 0.99). The lower limits of detection (LLOD) were 2.0 ng/mL for both drugs. The overall recoveries of CTB and GSB from rat plasma were in the range of 93.93–101.43%, and the mean relative standard deviation (RSD) of the results was 2.99%. The validated-method was successfully applied for the first time, to a pharmacokinetic study on concurrent oral administration of CTB and GSB in rats (12.0 mg/kg of CTB and 8.5 mg/kg of GSB). The maximum plasma concentration (Cmax) for CTB and GSB was 2312.23 ± 448.26 ng/mL and 1710.61 ± 166.04 ng/mL achieved at 2.83 ± 0.14 h and 2.39 ± 0.10 h, respectively. The AUC0-∞ for CTB and GSB was found to be 8592.49 ± 1714.12 and 4527.67 ± 390.01 ng/mL.h; respectively. The elimination half-life (t1/2kel) of CTB and GSB in rat plasma, were determined to be 2.00 ± 0.19 h and 1.58 ± 0.13 h, respectively. The newly developed approach stands out for its high extraction recovery and absence of matrix interference. Findings further demonstrated the high sensitivity of the developed method, which allowed for effective routine tests in pharmacokinetic investigations with LLOD of 2.0 ng/mL and a run time of 3.5 min.