An ultrasensitive LC-MS/MS method with liquid phase extraction to determine paclitaxel in both cell culture medium and lysate promising quantification of drug nanocarriers release in vitro

The quantification of paclitaxel, a chemotherapy drug used to treat different types of cancers, has been performed from complete cell culture medium and cell lysate samples using a simple liquid-liquid extraction procedure in conjunction with liquid chromatography tandem mass spectrometry (LC-MS/MS). A simple sample preparation using methanol and acetic acid as a weaker acid was applied to avoid paclitaxel destruction and to achieve recovery exceeding 80 % from both matrices spiked with paclitaxel and docetaxel used as internal standard. This rapid, simple, selective and sensitive method enabled the quantification of paclitaxel within the linear range of 1-250 nM in culture medium and 5-250 nM in cell lysate. The lower limit of quantification was achieved in cell culture medium and cell lysates at 0.2 and 1 pmol, respectively. This method was successfully applied to human non-small cell lung carcinoma cells (A549 cells) in order to quantify the amount of paclitaxel in both cell culture medium and lysate after incubation with 5, 50 and 100 nM of paclitaxel. This ultra-sensitive method promises the quantification of ultra-low concentrations of paclitaxel released from any nanocarriers, allowing the determination of the kinetic profile of drug release, which is an essential parameter to validate the use of nanocarriers for drug delivery in cancer therapy. (C) 2015 Elsevier B.V. All rights reserved.