HPLC-DAD protein kinase inhibitor analysis in human serum

We here describe an HPLC-DAD method to analyse different protein kinase inhibitors. Potential applications of this method are pharmacokinetic studies and therapeutic drug monitoring. Optimised chromatography conditions resulted in a very good separation of seven inhibitors (vatalanib, bosutinib, canertinib, tandutinib, pazopanib, dasatinib - internal standard and erlotinib).The good sensitivity makes this method competitive with LC/MS/MS. The separation was performed with a Lichrospher 100-5 RP8, 250 mm x 4 mm column maintained at 30 +/- 1 degrees C, and with a mobile phase of 0.05 M H3PO4/KH2PO4 (pH = 2.3)-acetonitrile (7:3, v/v) at a flow rate of 0.7 mL/min. A simple and fast sample preparation sequence with liquid-liquid extraction led to good recoveries (73-90%) of all analytes. The recovery hardly reached 50% only for pazopanib. This method can also be used for targeted protein kinase inhibitor quantification. A perfect linearity in the validated range (20-10,000 ng/mL) and an LOQ of 20 ng/mL were achieved. The relative standard deviations and accuracies of all examined drug concentrations gave values much lower than 15% both for between- and within-batch calculations. All analysed PKIs were stable for 6 months in a 1 mg/mL dimethyl sulfoxide stock solution. Vatalanib, bosutinib and erlotinib were also stable in human serum in the whole examined concentration range. (C) 2012 Elsevier B.V. All rights reserved.