[show abstract][hide abstract] ABSTRACT: The purpose of this study was to explore the role of the organic anion-transporting polypeptide (OATP) 1A2, which is encoded by SLCO1A2, in the cellular uptake of the Bcr-Abl tyrosine kinase inhibitor imatinib, and the relationship between SLCO1A2 polymorphisms and the pharmacokinetics of imatinib in patients with chronic myeloid leukemia (CML). Imatinib uptake was significantly enhanced in OATP1A2-transfected human embryonic kidney (HEK) 293 cells (P = 0.002). Naringin, an OATP1A2 inhibitor, decreased the transport of imatinib in OATP1A2-transfected HEK293 cells, the human intestinal cell line Caco-2, and K562 CML cells. Linkage disequilibrium was found between the SLCO1A2 -1105G>A and -1032G>A genotypes in 34 CML patients and 100 healthy subjects. Imatinib clearance in CML patients was influenced by the SLCO1A2 -1105G>A/-1032G>A genotype (P = 0.075) and the SLCO1A2 -361GG genotype (P = 0.005). These findings suggest that imatinib is transported into cells by OATP1A2, and that SLCO1A2 polymorphisms significantly affect imatinib pharmacokinetics.
[show abstract][hide abstract] ABSTRACT: A precise and convenient high-performance liquid chromatography (HPLC) method has been established to assay nilotinib in human plasma. Chromatographic separation of nilotinib was performed on a LiChrosphere(®)100 RP-18(e) column (250 mm×4.0 mm, 5 µm) using a mixture of acetonitrile and 0.01 M phosphate buffer (pH 3.0) (42 : 58, v/v) under isocratic conditions at a flow rate of 1.0 ml/min with ultraviolet (UV) detection at 266 nm. The calibration curve showed linearity at concentrations between 250 ng/ml and 5000 ng/ml (r(2)>0.999). The mean±S.D. absolute recovery of nilotinib from plasma was 99.2±3.3%. The coefficients of variation of both intra- and inter-day precision were below 9.1%. These results indicate that this new HPLC-based quantification may be useful for therapeutic drug monitoring of nilotinib to help manage treatment in patients with chronic myeloid leukemia in clinical practice.