Development and Validation of a Selective and Robust LC-MS/MS Method, Employing Liquid–Liquid Extraction Based on 96-Well Format Plates, for High-Throughput Quantification of Docetaxel in Small Plasma Samples

Abstract

To investigate the pharmacokinetic characteristics of a novel nanoliposome-entrapped docetaxel injection, an anti-tumor agent, a high-throughput analytical method based on liquid chromatography with positive ion electrospray ionization (ESI) coupled to tandem mass spectrometry detection (LC-MS/MS) was developed for the determination of docetaxel in beagle dog plasma using paclitaxel as the internal standard (I.S.). Most liquid transfer steps, including preparation of calibration standards and quality control samples, as well as the addition of the I.S., were performed by using eight-channel pipetting tools. The analyte and internal standard were isolated from 50 µL plasma samples and chromatographed on a Ultimate XB C-8 column (50 mm × 4.6 mm, 5 µm) with a mobile phase consisting of methanol–water–formic acid (90:10:0.01, v/v/v)pumped at 0.3 mL/min. The method had a chromatographic total run time of 3 min. A Varian 1200 L electrospray tandem mass spectrometer equipped with an electrospray ionization source was operated in selected reaction monitoring (SRM) mode with the precursor-to-product ion transitions m/z 830.0 → 549.0 (docetaxel) and 876.0 → 591.0 (paclitaxel) used for quantitation. The method was sensitive, with a lower limit of quantitation (LLOQ) of 1 ng/mL and good linearity in the range 1–500 ng/mL for docetaxel. All the validation data, such as accuracy, precision, and inter-day repeatability, were within the required limits. The method was successfully applied to initial pharmacokinetic study of nanoliposome-entrapped docetaxel injection in beagle dogs, and the statistical results of the pharmacokinetic data clearly suggest the novel formulation vehicle does control docetaxel's acute side effects to some extent.