Enzymatic tumour tissue digestion coupled to SPE–UPLC–Tandem Mass Spectrometry as a tool to explore paclitaxel tumour penetration

Development and validation of an UPLC-MS/MS method for the determination of irinotecan (CPT-11), SN-38 and SN-38 glucuronide in human plasma and peritoneal tumor tissue from patients with peritoneal carcinomatosis

Irinotecan (CPT-11), an antineoplastic drug, is used for the treatment of colorectal and pancreatic cancer due to its topoisomerase I inhibitory activity. CPT-11 is a prodrug which is converted to its active metabolite SN-38 by carboxylesterases. SN-38 is further metabolized to its inactive metabolite SN-38 glucuronide. When evaluating the pharmacokinetic properties of CPT-11 and its metabolites, it is important to accurately assess the concentrations in both plasma as well as tumor tissues. Therefore, the aim of the current study was to develop and validate a robust and sensitive ultra-high performance liquid chromatography-tandem mass spectrometry method to quantify the concentration of CPT-11 and its metabolites (SN-38 and SN-38 glucuronide) in human plasma and peritoneal tumor tissue. The sample preparation of plasma and tumor tissue consisted of protein precipitation and enzymatic digestion/liquid-liquid extraction, respectively. Chromatographic separation was achieved with an Acquity UPLC BEH C18 column combined with a VanGuard pre-column. The mobile phases consisted of water +0.1 % formic acid (mobile phase A) and acetonitrile +0.1 % formic acid (mobile phase B). Mass analysis was performed using a Xevo TQS tandem mass spectrometer in the positive electrospray ionization mode. Method validation was successfully performed by assessing linearity, precision and accuracy, lower limit of quantification, carry over, selectivity, matrix effect and stability according to the following guidelines: "Committee for Medicinal Products for Human use, Guideline on Bioanalytical Method Validation". A cross-validation of the developed method was performed in a pilot pharmacokinetic study, demonstrating the usefulness of the current method to quantify CPT-11 and its metabolites in the different matrices.

Development of polyanion-metal ion solution systems to overcome phospholipids-related matrix effects in LC-MS/MS-based bioanalysis

Phospholipids-related matrix effects are a major source impacting the reproducibility of analyte quantification in LC-MS/MS-based bioanalysis. This study intended to evaluate different combinations of polyanion-metal ion based solution system for phospholipids removal and elimination of matrix effects in human plasma. Blank plasma samples or plasma samples spiked with model analytes were proceeded with different combinations of polyanions (dextran sulfate sodium (DSS) and alkalized colloidal silica (Ludox)) and metal ions (MnCl₂, LaCl₃, and ZrOCl₂) followed with acetonitrile-based protein precipitation. The representative classes of phospholipids and model analytes (acid, neutral, and base) were detected using multiple reaction monitoring mode. The polyanion-metal ion systems were explored for providing balanced analyte recovery and phospholipids removal by optimizing reagent concentrations or adding formic acid and citric acid as the shielding modifiers. The optimized polyanion-metal ion systems were further evaluated for eliminating matrix effects of non-polar and polar compounds. Any combinations of polyanions (DSS and Ludox) and metal ions (LaCl₃ and ZrOCl₂) could completely remove phospholipids at best-case scenario, while the analyte recovery is low for compounds with special chelation groups. Addition of formic acid or citric acid can improve analyte recovery but significantly decrease the removal efficiency of phospholipids. Optimized ZrOCl₂-Ludox/DSS systems provided efficient phospholipids removal (>85%) and adequate analyte recovery, and the systems also correctly eliminated ion suppression or enhancement of the non-polar and polar drugs. The developed ZrOCl₂-Ludox/DSS systems are cost-effective and versatile for balanced phospholipids removal and analyte recovery and provide adequate elimination of matrix effects.

Antineoplastic drugs and their analysis: a state of the art review

We provide an overview of the analytical methods available for the quantification of antineoplastic drugs in pharmaceutical formulations, biological and environmental samples.