Utility of mass spectrometry for pharmaceutical profiling applications

MS has great utility for pharmaceutical profiling, the measurement of physicochemical and metabolic properties that are crucial to the discovery and development of new drug candidates. An evaluation of the capabilities of MS to improve the speed, specificity, sensitivity and cost per compound of method in development indicates when MS technologies have utility compared to other analytical techniques. MS has been used successfully for methods that profile the critical properties: permeability, lipophilicity, plasma and solution stability, solubility, plasma protein binding and integrity. In general, MS has utility in these methods using analytical strategies involving unique MS technologies (e.g., parallel multiplexed interfaces, trap-and-elute), orthogonal detection to UV, high sensitivity for low LOQs, low concentration studies, highly specific MS/MS SRM, combinatorial analysis, use of internal standards, providing initial structural data in addition to quantitative and facile integration with HPLC autosamplers and other hardware that allow enhanced on-line experiments. Ultimately, it is important to evaluate the appropriateness of any technique that is being considered for use in a method, to insure that it best meets all of the criteria for the organization's needs.     

A novel high-throughput automated chip-based nanoelectrospray tandem mass spectrometric method for PAMPA sample analysis

Parallel artificial membrane permeability assay (PAMPA) has recently gained popularity as a novel, high-throughput assay capable of rapidly screening compounds for their permeability characteristics in early drug discovery. The analytical techniques typically used for PAMPA sample analysis are HPLC-UV, LC/MS or more recently UV-plate reader. The LC techniques, though sturdy and accurate, are often labor and time intensive and are not ideal for high-throughput. On the other hand, UV-plate reader technique is amenable to high-throughput but is not sensitive enough to detect the lower concentrations that are often encountered in early drug discovery work. This article investigates a novel analytical method, a chip-based automated nanoelectrospray mass spectrometric method for its ability to rapidly analyze PAMPA permeability samples. The utility and advantages of this novel analytical method is demonstrated by comparing PAMPA permeability values obtained from nanoelectrospray to those from conventional analytical methods. Ten marketed drugs having a broad range of structural space, physico-chemical properties and extent of intestinal absorption were selected as test compounds for this investigation. PAMPA permeability and recovery experiments were conducted with model compounds followed by analysis by UV-plate reader, UV-HPLC as well as the automated nanoelectrospray technique (nanoESI-MS/MS). There was a very good correlation (r(2) > 0.9) between the results obtained using nanoelectrospray and the other analytical techniques tested. Moreover, the nanoelectrospray approach presented several advantages over the standard techniques such as higher sensitivity and ability to detect individual compounds in cassette studies, making it an attractive high-throughput analytical technique. Thus, it has been demonstrated that nanoelectrospray analysis provides a highly efficient and accurate analytical methodology to analyze PAMPA samples generated in early drug discovery.     

Rapid detection and subsequent isolation of bioactive constituents of crude plant extracts

Rapid detection of biologically active natural products plays a strategic role in the phytochemical investigation of crude plant extracts. In order to perform an efficient screening of the extracts, both biological assays and HPLC analysis with various detection methods are used. Combined techniques such as HPLC coupled to UV photodiode array detection (LC/UV) and to mass spectrometry (LC/MS or LC/MS/MS) provide useful structural information on the metabolites on-line prior to isolation. The recent introduction of HPLC coupled to nuclear magnetic resonance (LC/NMR) represents a powerful complement to the LC/UV/MS screening. Various plants belonging to the Gentianaceae and Leguminosae families have been analysed by LC/UV, LC/MS, LC/MS/MS, and LC/NMR. The use of all these coupled techniques allows the structural determination of known plant constituents rapidly and with only a minute amount of plant material. With such an approach, the time-consuming isolation of common natural products is avoided and an efficient targeted isolation of compounds presenting interesting chemical or biological features can be performed.     

Mass spectrometry in toxinology: a 21st-century technology for the study of biopolymers from venoms.

Mass spectrometry, developed in the early days of the 20th century for the structural analysis of ions from organic compounds, has evolved from an analytical technique almost entirely applied to structural studies of small molecules, to a diversified technology that is now increasingly focused on the study of biological macromolecules. Novel instrument developments and appropriate ionization techniques have permitted the application of mass spectrometry to the analysis of biopolymers such as proteins, sugars and nucleic acids and have opened the door to a multiplicity of applications, and not the least being proteomics. Increasingly used as a basic analytical tool in biology laboratories, mass spectrometry has now found another niche of application in the field of venom and toxin studies. The technique is well suited to the analysis of peptide and protein components of venoms, be it for global mass mapping of complex mixtures or structural studies on individual toxins. Further enhanced by hyphenation with separation technologies, mass spectrometry is well adapted to de-convolve the extreme complexity of natural venoms and biological extracts in which toxinologists specialize. This special issue highlights a number of applications of mass spectrometry in this field and presents some of the most recent work illustrating the benefits of various state-of-the-art mass spectrometry technologies for the study of animal venoms and toxins.     

Analytical methods for the monitoring of solid phase organic synthesis

Solid phase synthesis (SPS) is a powerful technique to assemble compound libraries in high-throughput parallel and combinatorial synthesis. The widespread applications of these techniques required the development of analytical methods for both structural elucidation and reaction monitoring. This review covers some recently developed techniques for on-bead analyses together with solution-state ones. Particular emphasis is devoted to software and hardware improvements for automated high-throughput analysis.     

Identification of Pharmaceutical Impurities in Formulated Dosage Forms

Structure elucidation of pharmaceutical impurities is an important part of the drug product development process. Impurities can have unwanted pharmacological or toxicological effects that seriously impact product quality and patient safety. This review focuses on current analytical strategies for chemical and structural identification of pharmaceutical impurities. Potential sources and mechanisms of impurity formation are discussed for both drug substance and drug product applications. The utility of liquid chromatography–mass spectrometry (LC/MS) for providing structure-rich information is highlighted throughout this review. Other hyphenated analytical techniques including LC/nuclear magnetic resonance, gas chromatography/MS, and size-exclusion chromatography/chemiluminescent nitrogen detectors are also discussed, as LC/MS alone sometimes cannot reveal or confirm the final structures as required during dosage form development.     

The devil is still in the details--driving early drug discovery forward with biophysical experimental methods

This review comments on some recent trends and insights in the field of lead identification and optimization with a bias toward the increased use of biophysical methods, particularly in combination with three-dimensional structural information. While high-throughput screening, combinatorial chemistry and, most recently, in silico virtual screening techniques have made well-resourced but only partially successful attempts to meet the challenge of identifying new drug candidates by playing 'the large numbers game', another group of technologies are now approaching the same challenge from what might be considered the opposite extreme. The common strategy of these technologies is to focus on a smaller set of low-molecular-weight compounds whose interactions with a target are characterized with the aid of sensitive assays, most often high-quality biophysical techniques such as biosensors, calorimetry, nuclear magnetic resonance spectroscopy and X-ray crystallography. The advantages of such an approach include more optimal and chemically attractive starting points, immediate access to reliable measurements of binding properties, the mapping of ligand interactions on the atomic level and, most importantly, a greater control of experimental errors at the initial stages of drug discovery where compounds are either discovered or lost. When correctly supported, this more careful approach appears to deliver quality leads, even for the so-called 'difficult' targets. As these techniques are complementary to traditional methods, companies should be less hesitant to invest in them. The biophysical methods that are used to drive this approach have made something of a return to drug discovery after having been discarded for being too slow, too expensive or too old-fashioned by the over-optimistic supporters of high-throughput and statistical/computational in silico methods.     

Fundamental aspects of chiral electromigration techniques and application in pharmaceutical and biomedical analysis

Capillary electromigration techniques are often considered ideal methods for the analysis of chiral compounds due to the high resolution power and flexibility of the technique. Therefore, especially capillary electrophoresis using a chiral selector in the background electrolyte, also termed electrokinetic chromatography, has found widespread acceptance in analytical enantioseparations of drug compounds in pharmaceuticals and biological media. Moreover, mechanistic studies on analyte complexation by the chiral selectors have continuously been conducted in an effort to rationalize enantioseparation phenomena. These studies combined capillary electrophoresis with spectroscopic techniques such as nuclear magnetic resonance and/or molecular modeling. The present review focuses on recent examples of mechanistic aspects of capillary electromigration enantioseparations and summarizes recent applications of chiral pharmaceutical and biomedical analysis published between January 2009 and August 2010.     

Emerging Technologies for Mycotoxin Detection

The history of the development of analytical methods for detecting fungal toxins is rich and varied. Method development has followed a process somewhat akin to Darwinian evolution: methods are selected based upon the characteristics most desirable to the analyst. Typically, this has lead to the development of accurate and sensitive methods for their detection, with a recurring emphasis on improving the speed and lowering the costs of the assays. Like evolution, there have been radical developments, incremental developments, and techniques that have fallen from favor only to be rediscovered. This review focuses on recent developments in technologies for detection of mycotoxins, with a particular emphasis on the myriad forms of biosensors that have begun to appear. Specifically, recent development in evanescent wave technologies (surface plasmon resonance, fiber optic sensors), lateral flow and dipstick devices, fluorescence polarization and time‐resolved fluorescence, microbead assays, and capillary electrophoretic immunoassays, are described. The challenge for the emerging technologies is to demonstrate advantages over the more conventional, and better established, techniques in settings outside the analytical laboratory.     

Protein aggregation: pathways, induction factors and analysis

Control and analysis of protein aggregation is an increasing challenge to pharmaceutical research and development. Due to the nature of protein interactions, protein aggregation may occur at various points throughout the lifetime of a protein and may be of different quantity and quality such as size, shape, morphology. It is therefore important to understand the interactions, causes and analyses of such aggregates in order to control protein aggregation to enable successful products. This review gives a short outline of currently discussed pathways and induction methods for protein aggregation and describes currently employed set of analytical techniques and emerging technologies for aggregate detection, characterization and quantification. A major challenge for the analysis of protein aggregates is that no single analytical method exists to cover the entire size range or type of aggregates which may appear. Each analytical method not only shows its specific advantages but also has its limitations. The limits of detection and the possibility of creating artifacts through sample preparation by inducing or destroying aggregates need to be considered with each method used. Therefore, it may also be advisable to carefully compare analytical results of orthogonal methods for similar size ranges to evaluate method performance.     

Arsenic in edible macroalgae: an integrated approach

ABSTRACT

Arsenic is a metalloid naturally present in marine environments. Various toxic elements including arsenic (As) are bioaccumulated by macroalgae. This metalloid is subsequently incorporated as arsenate into the organism due to similarity to phosphate. In recent decades, the use of macroalgae in food has increased as a result of their numerous benefits; however, As consumption may exert potential consequences for human health. The objective of this review was to discuss the articles published up to 2019 on As in seaweed, including key topics such as speciation, toxicity of the most common species in marine macroalgae, and their effects on human health. Further, this review will emphasize the extraction methods and analysis techniques most frequently used in seaweed and the need to develop certified reference materials (CRMs) in order to support the validation of analytical methodologies for As speciation in macroalgae. Finally, this review will discuss current legislation in relation to the risk associated with consumption. The number of articles found and the different approaches, biological, analytical and toxicological, show the growing interest there has been in this field in the last few years. In addition, this review reveals aspects of As chemistry that need further study, such as transformation of organic metalloid species during digestion and cooking, which necessitates analytical improvement and toxicological experiments. Taken together our findings may contribute to revision of current legislation on As content in edible seaweed relating to human health in a growing market.     

Application of metabonomic analytical techniques in the modernization and toxicology research of traditional Chinese medicine

In the recent years, a wide range of metabonomic analytical techniques are widely used in the modern research of traditional Chinese medicine (TCM). At the same time, the international community has attached increasing importance to TCM toxicity problems. Thus, many studies have been implemented to investigate the toxicity mechanisms of TCM. Among these studies, many metabonomic-based methods have been implemented to facilitate TCM toxicity investigation. At present, the most prevailing methods for TCM toxicity research are mainly single analysis techniques using only one analytical means. These techniques include nuclear magnetic resonance (NMR), gas chromatography-mass spectrometry (GC-MS), and liquid chromatography-mass spectrometry (LC-MS), etc.; with these techniques, some favourable outcomes have been gained in the toxic reaction studies of TCM, such as the action target organs assay, the establishment of action pattern, the elucidation of action mechanism and the exploration of action material foundation. However, every analytical technique has its advantages and drawbacks, no existing analytical technique can be versatile. Multi-analysed techniques can partially overcome the shortcomings of single-analysed techniques. Combination of GC-MS and LC-MS metabolic profiling approaches has unravelled the pathological outcomes of aristolochic acid-induced nephrotoxicity, which can not be achieved by single-analysed techniques. It is believed that with the further development of metabonomic analytical techniques, especially multi-analysed techniques, metabonomics will greatly promote TCM toxicity research and be beneficial to the modernization of TCM in terms of extending the application of modern means in the TCM safety assessment, assisting the formulation of TCM safety norms and establishing the international standards indicators.     

Spectroscopic and statistical methods in metabonomics

Metabonomics is rapidly evolving through advances in analytical technologies together with the development of new hyphenated approaches that are increasingly being applied to analyze complex biological systems. Improvements in analytical performance, such as increased sensitivity and selectivity, are providing greater resolution to analytical datasets and the rich potential of metabonomics as a systems biology tool of choice is becoming clear. However, such improvements are resulting in datasets becoming increasingly demanding in terms of data handling and interpretation, and the degree to which metabonomics continues to develop will be dependent on how chemometrics and data-handling approaches keep pace with continually improving analytical technologies. This review provides an overview of the field of metabonomics, with a particular focus on the analytical techniques that are chiefly employed and the chemometric methods that have found most use. However, in addition, we mention less widely used analytical methods and suggest that advanced statistical methods will play a larger role in the future.     

补肾壮阳类药品中非法添加化学药物检测技术的研究进展

目的了解补肾壮阳类中成药和保健品中非法添加化学药物检测技术的研究进展。方法通过查阅相关文献和分析总结,对近年来补肾壮阳类中成药和保健品中非法添加化学药物检测技术的研究进展进行综述。结果补肾壮阳类中成药和保健品中非法添加的化学药物包括磷酸二酯酶-5抑制剂、蛋白同化制剂、α-肾上腺素受体阻滞剂、多巴胺受体激动剂和天然前列腺素类物质等。涉及的检测方法包括理化分析法、薄层色谱法、高效液相色谱法、液相色谱-质谱联用技术、直接实时分析-MS/MS法、中空纤维膜液相微萃取-车载HPLC法、离子迁移谱法、显微共聚焦拉曼光谱法和近红外光谱法等。结论补肾壮阳类中成药和保健品中非法添加化学药物的检测技术取得了一定进展。不断发展检测技术是一方面,从多方面加强监管也非常重要。     

代谢物组学的研究进展

代谢物组学是继基因组学和蛋白质组学发展起来的一门新的组学(-omics)技术,是研究药物毒理和基因功能的技术平台,通过分析生物的体液、组织中的内源性代谢产物谱的变化来研究整体的生物学状况和基因调节功能.代谢物组学所涉及的主要技术为核磁共振技术和模式识别分析.对代谢物组学研究的样品、核心技术、分析方法和应用等几方面作简要概述.     

β-榄香烯的分析检测方法及制备技术研究进展

目的介绍β-榄香烯的分析检测方法及制备技术研究进展。方法本文对榄香烯的双键异构及β-榄香烯的光学异构体分子结构、分析检测方法及制备技术进行了综述;进一步评述从天然植物中提取及分离β-榄香烯的方法及技术的优缺点。结果与结论气相或液相色谱结合核磁、质谱等光谱技术能较好地检测β-榄香烯成分及含量;众多植物挥发油富含β-榄香烯,采用真空精馏及柱层析联用技术能获得高纯度的β-榄香烯。     

New Polymorph Form of Dexamethasone Acetate

A new monohydrated polymorph of dexamethasone acetate was crystallized and its crystal structure characterized. The different analytical techniques used for describing its structural and vibrational properties were: single crystal and polycrystal X-ray diffraction, solid state nuclear magnetic resonance, infrared spectroscopy. A Hirshfeld surface analysis was carried out through self-arrangement cemented by H-bonds observed in this new polymorph. This new polymorph form appeared because of self-arrangement via classical hydrogen bonds around the water molecule.     

Inductively coupled plasma-MS in drug development: bioanalytical aspects and applications

The vast majority of today's modern bioanalytical methods for pharmacokinetic, pharmacodynamic and immunogenicity purposes are based on LC-MS/MS and immunoanalytical approaches. Indeed, these methodologies are suitable for a wide range of molecules from small to large. For a smaller but not insignificant group of compounds, LC-MS/MS is not suitable - or in some cases much less suitable - as a reliable bioanalytical methodology, and inductively coupled plasma (ICP)-MS is a more appropriate methodology. ICP-MS is one of these less widely used techniques in drug development. This methodology is predominantly used for elemental bioanalysis for pharmacokinetics, for imaging purposes, for mass-balance, food-effect and biomarker studies. In addition, in the last couple of years an increasing number of applications has been published, where ICP-MS and its various hyphenations (LC-ICP-MS, CE-ICP-MS) have been used for speciation/metabolism and proteomics studies. Here, the analytical potential, the quantitative bioanalytical aspects, the various modes of operation and the challenges of the application of ICP-MS in life sciences applications are given. This includes an overview of recent applications in this area in scientific literature, the various hyphenation possibilities and their application areas and the analysis of the various sample matrices applicable to these fields. It also provides a brief outlook of where the potential of this technique lies in the future of regulated bioanalysis and drug development.     

Nuclear magnetic resonance as a tool in drug discovery, metabolism and disposition

Nuclear magnetic resonance techniques have become critically important in the design of new pharmaceuticals, the characterization of drug-receptor interactions and metabolite identification. Advances in solvent suppression, coherent and incoherent magnetization transfer pathway selection, isotope editing and filtering, and diffusion filtering have made it possible to examine the interactions between small molecules and proteins or nucleic acids in great detail. Multiple schemes for high-throughput lead compound identification, metabolite screening and drug disposition have been proposed and reduced to practice. In particular, the coupling of NMR with other analytical methods, especially HPLC, combine the structural and dynamic detail available from NMR methods with the resolution and sensitivity of other analytical techniques.