Development and clinical application of a LC-MS/MS method for simultaneous determination of various tyrosine kinase inhibitors in human plasma.

Background: Increasing numbers of tyrosine kinase inhibitors (TKIs) were studied and approved for therapy of malignancies and other diseases. The aim of this study was to develop and validate a specific, simple and rapid quantification method for various TKIs in human plasma.

Methods: A simultaneous test for six TKIs (erlotinib, imatinib, lapatinib, nilotinib, sorafenib, sunitinib) was developed using liquid chromatography tandem mass spectrometry in a multiple reaction monitoring mode. After protein precipitation the specimens were applied to the HPLC system and separated using a gradient of acetonitrile containing 1% formic acid with 10 mM ammoniumformiate on an analytic RP-C18 column.

Results: The calibration range was 10-1000 ng/mL for sunitinib and 50-5000 ng/mL for the other TKIs with coefficients of determination ≥0.99 for all analytes. The intra- and inter day coefficients of variation were ≤15% and the chromatographic run time was 12 min. Plasma specimens were stable for measurement for at least 1 week at 4°C. Clinical applications of the assay are exemplarily discussed.

Conclusions: This novel high-throughput method is suitable for specific simultaneous determination of different TKIs in routine clinical practice.