A new high-performance liquid chromatography-tandem mass spectrometry method for the determination of paclitaxel and 6α-hydroxy-paclitaxel in human plasma: Development, validation and application in a clinical pharmacokinetic study

Abstract

Paclitaxel belongs to the taxanes family and it is used, alone or in multidrug regimens, for the therapy of several solid tumours, such as breast-, lung-, head and neck-, and ovarian cancer. Standard dosing of chemotherapy does not take into account the many inter-patient differences that make drug exposure highly variable, thus leading to the insurgence of severe toxicity. This is particularly true for paclitaxel considering that a relationship between haematological toxicity and plasma exposure was found. Therefore, in order to treat patients with the correct dose of paclitaxel, improving the overall benefit–risk ratio, Therapeutic Drug Monitoring is necessary. In order to quantify paclitaxel and its main metabolite, 6α-hydroxy-paclitaxel, in patients’ plasma, we developed a new, sensitive and specific HPLC–MS/MS method applicable to all paclitaxel dosages used in clinical routine. The developed method used a small volume of plasma sample and is based on quick protein precipitation. The chromatographic separation of the analytes was achieved with a SunFire™ C18 column (3.5 μM, 92 Å, 2,1 x 150 mm); the mobile phases were 0.1% formic acid/bidistilled water and 0.1% formic acid/acetonitrile. The electrospray ionization source worked in positive ion mode and the mass spectrometer operated in selected reaction monitoring mode. Our bioanalytical method was successfully validated according to the FDA-EMA guidelines on bioanalytical method validation. The calibration curves resulted linear (R2 ≥0.9948) over the concentration ranges (1–10000 ng/mL for paclitaxel and 1–1000 ng/mL for 6α-hydroxy-paclitaxel) and were characterized by a good accuracy and precision. The intra- and inter-day precision and accuracy were determined on three quality control concentrations for paclitaxel and 6α-hydroxy-paclitaxel and resulted respectively <9.9% and within 91.1–114.8%. In addition, to further verify the assay reproducibility, we tested this method by re-analysing the incurred samples. This bioanalytical method was employed with success to a genotype-guided phase Ib study of weekly paclitaxel in ovarian cancer patients treated with a wide range of drug’s dosages.

Simultaneous quantification of palbociclib, ribociclib and letrozole in human plasma by a new LC-MS/MS method for clinical application

“…A full validation of the proposed method was conducted according to FDA and EMA guidelines on bioanalytical method validation [23,24], as previously reported [25,26].…”

“…Firstly, this phenomenon was investigated by means of the post-column infusion using standard solutions of the three analytes in 0.1% HCOOH methanol/water 1:1 at the concentration of 50 ng/mL and applying a flow rate of 20 μL/min. For more details on post-column infusion experiment see our previous published methods [25,26]. The matrix effect was then evaluated by calculating for each analyte the ratio of the peak area of set 2 QCs to the peak area of set 3 QCs.…”

A phase Ib/II study of regorafenib and paclitaxel in patients with beyond first-line advanced esophagogastric carcinoma (REPEAT)

“…Paclitaxel was analyzed using liquid chromatography-mass spectrometry with a detection limit of 1 ng/mL. 26 Concentration versus time data were elaborated according to non-compartmental pharmacokinetic analysis for intravenous infusion. 27 Exploratory analyses were performed on all patients receiving 120 mg regorafenib: dose-expansion cohort ( N = 34) and dose-escalation cohort ( N = 7).…”

Natural Taxanes: From Plant Composition to Human Pharmacology and Toxicity

“…The effect of the drug on the organism should be therapeutically monitored using basic pharmacokinetic parameters (PK), for example its maximum concentration in the blood (C max ) [ 77 ]. However, an even more important parameter is its concentration in the local therapeutic site, in the case of taxanes inside the tumour cell.…”