- The Pharmaceutical Society of Japan
- Biological and Pharmaceutical Bulletin (ISSN:09186158)
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 (250 mm × 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/day. 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 ng/mL 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.