Bioanalytical strategies in drug discovery and development

A reliable, rapid, and effective bioanalytical method is essential for the determination of the pharmacokinetic, pharmacodynamic, and toxicokinetic parameters that inform the safety and efficacy profile of investigational drugs. The overall goal of bioanalytical method development is to elucidate the procedure and operating conditions under which a method can sufficiently extract, qualify, and/or quantify the analyte(s) of interest and/or their metabolites for the intended purpose. Given the difference in the physicochemical properties of small and large molecule drugs, different strategies need to be adopted for the development of an effective and efficient bioanalytical method. Herein, we provide an overview of different sample preparation strategies, analytical platforms, as well as procedures for achieving high throughput for bioanalysis of small and large molecule drugs.

Quantification of ondansetron, granisetron and tropisetron in goat plasma using hydrophilic interaction liquid chromatography-solid phase extraction coupled with hydrophilic interaction liquid chromatography-triple quadrupole tandem mass spectrometry

An assay method to quantify ondansetron (OND), granisetron (GRA) and tropisetron (TRO) in goat plasma has been successfully developed and validated. This method procedure for the analysis of OND, GRA and TRO was involved of extracting samples with hydrophilic interaction liquid chromatography (HILIC) solid phase extraction (SPE) and determination by liquid chromatography coupled to tandem mass spectroscopy. An SPE method for the simultaneous extraction of OND, GRA and TRO with high efficiency and selectivity was developed. Prior to HPLC-MS/MS analysis, most of the sources of interference present in the supernatant after protein precipitation of plasma proteins was efficiently removed from the samples by the HILIC SPE treatment. For the quantification of OND, GRA and TRO in the samples, tandem mass spectrometry operating in positive electrospray ionization mode with multiple reaction monitoring was used. The calibration curve was performed in the range of 0.2-20 ng/mL for the target OND, GRA and TRO in goat plasma samples. The precision of the intra- and inter-day assay for OND, GRA and TRO were 1.84-6.23% and 3.89-5.31%, 2.63-6.29% and 3.76-5.31%, 1.99-5.67% and 2.64-4.70%, respectively. The accuracy of the intra- and inter-day assay for OND, GRA and TRO were 89.15-97.39% and 89.46-95.17%, 91.08-100.82% and 91.24-99.47%, 92.30-100.74% and 94.21-97.90%, respectively. For the determination of OND, GRA and TRO in plasma samples, no significant matrix effects were observed. The mean absolute recoveries were 103-150%, 115-121%, and 98-141% for OND, GRA and TRO, respectively. Furthermore, the mean process efficiency values of silica SPE were 98-135%, 92-124%, and 72-109% for OND, GRA and TRO, respectively.

Efficient discrimination and removal of phospholipids during electromembrane extraction from human plasma samples

Aim: For the first time, extracts obtained from human plasma samples by electromembrane extraction (EME) were investigated comprehensively with particular respect to phospholipids using ultra-high-performance liquid chromatography tandem mass spectrometry (UHPLC–MS/MS). Thhe purpose was to investigate the potential of EME for phospholipid cleanup in different EME systems. Results & discussion: No traces of phospholipids were detected in any of the acceptor solutions, whereas the model analytes were extracted with recoveries up to 50%. Thus, the EME systems tested in this work were found to be highly efficient for providing phospholipid-free extracts. Conclusion: Ultra-HPLC–MS/MS analysis of the donor solutions revealed that the phospholipids principally remained in the plasma samples. This proved that the phospholipids did not migrate in the electrical field and they were prevented from penetrating the supported liquid membrane.

Current state-of-the-art of nontargeted metabolomics based on liquid chromatography-mass spectrometry with special emphasis in clinical applications

Metabolomics, as a part of systems biology, has been widely applied in different fields of life science by studying the endogenous metabolites. The development and applications of liquid chromatography (LC) coupled with high resolution mass spectrometry (MS) greatly improve the achievable data quality in non-targeted metabolic profiling. However, there are still some emerging challenges to be covered in LC-MS based metabolomics. Here, recent approaches about sample collection and preparation, instrumental analysis, and data handling of LC-MS based metabolomics are summarized, especially in the analysis of clinical samples. Emphasis is put on the improvement of analytical techniques including the combination of different LC columns, isotope coded derivatization methods, pseudo-targeted LC-MS method, new data analysis algorithms and structural identification of important metabolites.

SPE–MS analysis of absorption, distribution, metabolism and excretion assays: a tool to increase throughput and steamline workflow

In an effort to create faster and more efficient bioanalytical methods for drug development, many investigators have evaluated a variety of SPE–MS systems. Over the past 15 years online systems have evolved from run times of >1.5 min/sample to <10 s/sample. High-throughput SPE–MS methods for in vitro absorption, distribution, metabolism and excretion screening assays have been described by several laboratories and shown to produce results comparable to conventional LC–MS/MS systems. While quantitative analysis of small molecules in biological matrixes holds many challenges, for several applications SPE–MS methods have achieved comparable results to LC–MS/MS with the benefit of 10–30-times the throughput. Based on its distinct advantages of throughput and streamlined workflow efficiencies, SPE–MS is a useful tool for the analysis of many in vitro absorption, distribution, metabolism and excretion assays and in vivo bioanalytical studies. Further development of SPE–MS methods and analysis workflows has the potential to expand the capabilities of this technology for other challenging bioanalytical applications.