Quantification of topotecan by liquid chromatography–mass spectrometry (LC–MS). Application to intestinal transport using rat everted gut sacs

A sensitive bioanalytical ultra-high-performance liquid chromatography-tandem mass spectrometry method for the simultaneous quantitation of lactone and carboxylate forms of topotecan in plasma and vitreous

Topotecan (TPT) is used in the treatment of retinoblastoma, the most common malignant intraocular tumor in children. TPT undergoes pH-dependent hydrolysis of the lactone ring to the ring-opened carboxylate form, with the lactone form showing antitumor activity. A selective, and highly sensitive ultra-high-performance liquid chromatography-tandem mass spectrometry method was developed for the determination of both forms of TPT in one mobile phase composition in plasma and vitreous humor matrices. The method showed an excellent linear range of 0.375-120 ng/mL for the lactone. For the carboxylate, the linear range was from 0.75 to 120 ng/mL. The matrix effect and the recovery for the lactone ranged from 98.5% to 106.0% in both matrices, for the carboxylate form, it ranged from 94.9% to 101.2%. The dynamics of the transition between TPT lactone and TPT carboxylate were evaluated at different pH environments. The stability of TPT forms was assessed in plasma and vitreous humor at 8 and 37°C and a very fast conversion of lactone to carboxylate form occurred at 37°C in both matrices. The method developed facilitates the investigation of TPT pharmacodynamics and the release kinetics in the development of the innovative local drug delivery systems.

Dual-response electrochemical electrode for sensitive monitoring of topotecan and mitomycin as anticancer drugs in real samples

This research paper employed an innovative electrochemical electrode to simultaneously determine topotecan (TPT) and mitomycin (MMC) as anticancer agents. For this purpose, a novel nanocomposite was synthesized using a hydrothermal procedure. The nanocomposites were characterized using FTIR, STEM, FESEM, mapping analysis, EDX, and XRD methods. The novelty of this work is the successful synthesis of Fe₃O₄ decorated on the surface of CuCo₂S₄ (Fe₃O₄@CuCo₂S₄) nanocomposites showed two separate anodic peaks at 0.8 V for TPT and 1.0 V for MMC with potential separation of 0.2 V. This was enough for the simultaneous electrochemical determination of topotecan and mitomycin on a glassy carbon electrode (GCE), simultaneously. At optimized conditions, the developed electrode exhibited linear responses with TPT and MMC concentration in the ranges of 0.01-0.89 and 0.89-8.95 μM for topotecan and 0.1-19.53 μM for mitomycin. The detection limits were observed as 6.94 nM and 80.00 nM for topotecan and mitomycin, respectively. The fabricated Fe₃O₄@CuCo₂S₄/GCE showed high sensitivity, long-term stability, and repeatability towards the sensing of TPT and MMC simultaneously and can be utilized in real samples. The obtained results confirmed that the fabricated Fe₃O₄@CuCo₂S₄/GCE nanocomposites can be utilize in the simultaneous electrochemical determination of topotecan and mitomycin in real samples.

Mass spectrometry in the pharmacokinetic studies of anticancer natural products

In the history of medicine, nature has represented the main source of medical products. Indeed, the therapeutic use of plants certainly goes back to the Sumerian and Hippocrates and nowadays nature still represents the major source for new drugs discovery. Moreover, in the cancer treatment, drugs are either natural compounds or have been developed from naturally occurring parent compounds firstly isolated from plants and microbes from terrestrial and marine environment. A critical element of an anticancer drug is represented by its severe toxicities and, after administration, the drug concentrations have to remain in an appropriate range to be effective. Anyway, the drug dosage defined during the clinical studies could be inappropriate for an individual patient due to differences in drug absorption, metabolism and excretion. For this reason, personalized medicine, based on therapeutic drug monitoring (TDM), represents one of most important challenges in cancer therapy. Mass spectrometry sensitivity, specificity and fastness lead to elect this technique as the Golden Standard for pharmacokinetics and drug metabolism studies therefore for TDM. This review focuses on the mass spectrometry-based methods developed for pharmacokinetic quantification in human plasma of anticancer drugs derived from natural sources and already used in clinical practice. Particular emphasis was placed both on the pre-analytical and analytical steps, such as: sample preparation procedures, sample size required by the analysis and the limit of quantification of drugs and metabolites to give some insights on the clinical practice applicability. © 2015 Wiley Periodicals, Inc. Mass Spec Rev. 36:213-251, 2017.

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.

Quantitative Assessment of the Influence of Rhizoma Zingiberis on the Level of Aconitine in Rat Gut Sacs and Qualitative Analysis of the Major Influencing Components of Rhizoma Zingiberis on Aconitine Using UPLC/MS

This study attempted to clarify the material basis for the detoxification of Rhizoma Zingiberis (RZ) on aconitine, an analgesic drug, by quantitatively assessing the influence of RZ on the in vitro intestinal concentration of aconitine using an everted gut sac model and by qualitatively identifying the components in the RZ extract. To quantify aconitine in rat everted gut sacs, both an accurate processing method and a sensitive detection method were required. We developed a three-step sample processing method to protect the components from decomposition and applied ultra-performance liquid chromatography coupled with triple quadrupole mass spectrometry (UPLC/TQMS) to quantify aconitine, glucose and digoxin. In addition, ultra-performance liquid chromatography coupled with linear ion trap mass spectrometry (UPLC/ITMS) was applied to detect the potential antidotal components in the RZ extract. Finally, the RZ extract reduced the level of aconitine in everted gut sacs, and eleven gingerols were successfully identified, which could be considered potential antidotal components for aconitine. This study demonstrated the application of two UPLC/MS methods for analyzing the material basis for the reciprocity between Chinese medicine components in everted gut sacs.

Development and validation of a liquid chromatography-tandem mass spectrometry method for topotecan determination in beagle dog plasma and its application in a bioequivalence study

Topotecan (TPT) is an important anti-cancer drug that inhibits topoisomerase I. A sensitive and robust liquid chromatography-tandem mass spectrometry (LC-MS/MS) method that potentially determines TPT in beagle dog plasma is needed for a bioequivalence study of TPT formulations. We developed and validated LC-MS/MS to evaluate TPT in beagle dog plasma in terms of specificity, linearity, precision, accuracy, stability, extraction recovery and matrix effect. Plasma samples were treated with an Ostro(TM) sorbent plate (a robust and effective tool) to eliminate phospholipids and proteins before analysis. TPT and camptothecin (internal standard) were separated on an Acquity UPLC BEH C18 column (1.7 µm, 2.1 × 50 mm) with 0.1% formic acid and methanol as the mobile phase at a flow rate of 0.25 mL/min. TPT was analyzed using positive ion electrospray ionization in multiple-reaction monitoring mode. The obtained lower limit of quantitation was 1 ng/mL (signal-to-noise ratio > 10). The standard calibration curve for TPT was linear (correlation coefficient > 0.99) at the concentration range of 1-400 ng/mL. The intra-day and inter-day precision, accuracy, stability, extraction recovery and matrix effect of TPT were within the acceptable limits. The validated method was successfully applied in a bioequivalence study of TPT in healthy beagle dogs.

Topotecan exposure estimation in pediatric acute myeloid leukemia supported by LC-MS-based drug monitoring and pharmacokinetic analysis

Individualization of the topotecan dosing can reduce inter-patient variability, toxicity, and at the same time increases chemotherapy efficacy. Topotecan dosing based on simultaneous drug monitoring and pharmacokinetic analysis can yield more accurate and precise estimation of the topotecan systemic exposure than that attainable with the fixed dosing approach. Therefore, a combined approach could provide a tool assisting the clinicians in individualization of the topotecan dosing. The aim of the study was to estimate the topotecan exposure in pediatric patients with acute myeloid leukemia (AML) based on the plasma concentration-time data and using the pharmacokinetic analysis. The primary goal was achieve the correct estimation of the target plasma area against the topotecan concentration-time curve (AUC) in a 5 day course of cladribine followed by monitored topotecan in pediatric patients with recurrent/refractory AML. A sensitive and selective reversed-phase liquid chromatographic-mass spectrometry (LC-MS) assay was developed to quantify total topotecan in the human plasma samples. This method, with its lower quantification limit of 1 ng/ml, was validated over a linear range of 1-150 ng/ml. Under the proposed approach, the topotecan dosing was selected so as to achieve the final AUC value of 140±20 ng/ml h. The presented analytical and pharmacokinetic data demonstrate that the proposed approach can be a practical, useful, efficient, and accurate tool for individualizing the topotecan dosing in children with AML.