ABSTRACT
Ibrutinib is an oral inhibitor of Bruton tyrosine kinase, which is one of the key drugs used for the treatment of chronic lymphocytic leukemia and mantle cell lymphoma. In this study, we aimed to develop a simple method for determining plasma ibrutinib concentration. The analysis required extraction of a 200 µL plasma sample and precipitation of proteins using solid-phase extraction. Ibrutinib and nilotinib, which was used as an internal standard, were separated using high-performance liquid chromatography (HPLC) using a mobile phase of acetonitrile-0.5% monopotassium phosphate (KH2 PO4 , pH 3.0; 52:48, v/v) on a Capcell Pack C18 MG II (250 × 4.6 mm) monitored at 260 nm, at a flow rate of 1.0 mL/min. The calibration curve was linear at the plasma concentration range of 10-500 ng/mL with a coefficient of determination (r2 ) of 0.9999. The coefficients of intra-day and inter-day validation were 4.0-6.6 and 2.6-7.7%, respectively. The assay accuracy was -4.4-8.6%, and the recovery was >84%. This HPLC method coupled with ultraviolet (UV) detection for determining ibrutinib plasma concentration has several advantages such as simplicity and applicability to routine therapeutic drug monitoring at hospital laboratories.
Subject(s)
Chromatography, High Pressure Liquid/methods , Pyrazoles/blood , Pyrimidines/blood , Adenine/analogs & derivatives , Humans , Limit of Detection , Linear Models , Piperidines , Pyrazoles/chemistry , Pyrazoles/pharmacokinetics , Pyrimidines/chemistry , Pyrimidines/pharmacokinetics , Reproducibility of ResultsABSTRACT
Ponatinib, a novel tyrosine kinase inhibitor marketed in 2016, is a key drug used for treating chronic myeloid leukemia and Philadelphia chromosome-positive acute lymphoblastic leukemia. This study aimed to develop a simple method for determining plasma ponatinib concentration. The analysis required extraction of a 400-µL sample of plasma and precipitation of proteins using an Oasis HLB cartridge. Ponatinib and bosutinib, which is used as an internal standard, were separated by HPLC using a mobile phase of acetonitrile : 0.037 mol/L KH2PO4 (pH 4.5) (39 : 61, v/v) on a Capcell Pack C18 MG II (25×4.6 mm) monitored at 250 nm, with a flow rate of 1.0 mL/min. This assay method was then used for determining plasma ponatinib concentration in a 42-year-old man treated with ponatinib at 15 mg/d. The calibration curve was found to be linear for the plasma concentration range of 5-250 ng/mL with a regression coefficient (r2) of 0.9999. The coefficients of intra-day and inter-day validation under these concentrations were 2.1-6.0 and 4.5-8.0%, respectively. The assay accuracy was -1.5-9.0%, and the recovery was greater than 86%. The plasma concentration of the patient at 2.5 and 3 h after 15 mg ponatinib administration was 43.6 and 49.3 ng/mL, respectively. This method of HPLC equipped with UV detection for determining plasma ponatinib concentration has several advantages, such as simplicity and applicability to routine therapeutic drug monitoring at hospital laboratories.