Development and validation of a rapid and sensitive UPLC–MS/MS method for determination of total docetaxel from a lipid microsphere formulation in human plasma

Docetaxel lipid microsphere (DT-LM), an intravenous lipid emulsion for docetaxel without Tween 80, has demonstrated significant advantage over other conventional docetaxel formulations with respect to keeping sustained release, reducing irritation or toxicity of drug, sterile for intravenous injection and presenting targeting. A rapid, sensitive and reproducible ultra high performance liquid chromatography–tandem mass spectrometry (UPLC–MS/MS) method for determination of total docetaxel from a lipid microsphere formulation in human plasma using paclitaxel as internal standard (IS) has been developed and validated. The analytes and IS were extracted from plasma by simple liquid–liquid extraction and separated on ACQUITY UPLC BEH C18 column at a flow rate of 0.3 ml/min using gradient elution mode. The total analytical time was only 2.5 min. Detection and quantitation were performed by electrospray ionization (ESI) in the positive ionization mode by multiple reaction monitoring (MRM) of the transitions at m/z 808.3 → 527.1 for docetaxel and 854.0 → 285.9 for IS. The assay was linear over the concentration range of 2–5000 ng/ml (r2 > 0.99) with the lower limit of quantification (LLOQ) of 2 ng/ml. The intra- and inter-day precision in terms of relative standard deviation (RSD%) was within 9% and accuracy in terms of relative error (RE%) was within 12%. The rapid, sensitive and reproducible UPLC–MS/MS method is now used to support clinical pharmacologic studies with DT-LM injection in patients with advanced cancer.