Determination of Synacthen in urine for sports drug testing by means of nano-ultra-performance liquid chromatography/tandem mass spectrometry

DropWise: current role and future perspectives of dried blood spots (DBS), blood microsampling, and their analysis in sports drug testing

For decades, blood testing has been an integral part of routine doping controls. The breadth of information contained in blood samples has become considerably more accessible for anti-doping purposes over the last 10 years through technological advancements regarding analytical instrumentation as well as enhanced sample collection systems. Particularly, microsampling of whole blood and serum, for instance as dried blood spots (DBS), has opened new avenues in sports drug testing and substantially increased the availability and cost-effectiveness of doping control specimens. Thus, microvolume blood specimens possess the potential to improve monitoring of blood hormone and drug levels, support evaluation of circulating drug concentrations in competition, and enhance the stability of labile markers and target analytes in blood passport analyses as well as peptide hormone and steroid ester detection. Further, the availability of the fraction of lysed erythrocytes for anti-doping purposes warrants additional investigation, considering the sequestering capability of red blood cells (RBCs) for certain substances, as a complementary approach in support of the clean sport.

Nano liquid chromatography, an updated review

Low flow chromatography has a rich history of innovation but has yet to reach widespread implementation in bioanalytical applications. Improvements in pump technology, microfluidic connections, and nano-electrospray sources for mass spectrometry have laid the groundwork for broader application, and innovation in this space has accelerated in recent years. This article reviews the instrumentation used for nano-flow liquid chromatography , the types of columns employed, and strategies for multi-dimensionality of separations, which is key to the future state of the technique to the high-throughput needs of modern bioanalysis. An update of the current applications where nano-LC is widely used, such as proteomics and metabolomics, is discussed. But the trend towards biopharmaceutical development of increasingly complex, targeted, and potent therapeutics for the safe treatment of disease drives the need for ultimate selectivity and sensitivity of our analytical platforms for targeted quantitation in a regulated space. The selectivity needs are best addressed by mass spectrometric detection, especially at high resolutions, and exquisite sensitivity is provided by nano-electrospray ionization as the technology continues to evolve into an accessible, robust, and easy to use platform.

Enhanced urinary stability of peptide hormones and growth factors by dried urine microsampling

Volumetric absorptive microsampling (VAMS) and dried urine spot (DUS) strategies were applied for the collection of dried microsamples for anti-doping testing of low-stability peptide hormones and growth factors prohibited by the World Anti-Doping Agency (WADA). Drying, storage and transport conditions, as well as pretreatment steps, were optimised before liquid chromatography - tandem mass spectrometry (LC-MS/MS) analysis. The analytical method has been fully validated in terms of sensitivity (limits of quantitation 0.3-10 ng/mL), precision (RSD% < 6.6 %) and extraction yields (78-91 %). Dried microsample stability studies (90 days) have been performed and compared to fluid urine stability. Significantly higher losses have been observed in fluid urine stored at -20 °C (up to 55 %) and -80 °C (up to 29 %) than in dried urine microsamples stored at room temperature (< 19 %). The final microsampling and analysis protocols allow the collection of urine microvolumes, unlikely to be tampered, stably storable and shippable with no particular precautions for possible anti-doping testing of prohibited peptides and hormones.

Recent Trends in Fast Liquid Chromatography for Pharmaceutical Analysis

Background:

Liquid chromatography is the workhorse of analytical laboratories of pharmaceutical companies for analysis of bulk drug materials, intermediates, drug products, impurities and degradation products. This efficient technique is impeded by its long and tedious analysis procedures. Continuous efforts of scientists to reduce the analysis time resulted in the development of three different approaches namely, HTLC, chromatography using monolithic columns and UHPLC.

Methods:

Modern column technology and advances in chromatographic stationary phase including silica-based monolithic columns and reduction in particle and column size (UHPLC) have not only revolutionized the separation power of chromatographic analysis but also have remarkably reduced the analysis time. Automated ultra high-performance chromatographic systems equipped with state-ofthe- art software and detection systems have now spawned a new field of analysis, termed as Fast Liquid Chromatography (FLC). The chromatographic approaches that can be included in FLC are hightemperature liquid chromatography, chromatography using monolithic column, and ultrahigh performance liquid chromatography.

Results:

This review summarizes the progress of FLC in pharmaceutical analysis during the period from year 2008 to 2017 focusing on detecting pharmaceutical drugs in various matrices, characterizing active compounds of natural products, and drug metabolites. High temperature, change in the mobile phase, use of monolithic columns, new non-porous, semi-porous and fully porous reduced particle size of/less than 3μm packed columns technology with high-pressure pumps have been extensively studied and successively applied to real samples. These factors revolutionized the fast high-performance separations.

Conclusion:

Taking into account the recent development in fast liquid chromatography approaches, future trends can be clearly predicated. UHPLC must be the most popular approach followed by the use of monolithic columns. Use of high temperatures during analysis is not a feasible approach especially for pharmaceutical analysis due to thermosensitive nature of analytes.

Peptide enrichment by ion-pair solid-phase extraction

The technique of Solid-Phase Extraction (SPE) is widely used in various fields to concentrate samples and the search for tools to improve recoveries remains of outmost importance. The use of polymer based cartridges has become prevailing in a broad range of fields to enrich peptides from biological matrices. However, the existing SPE protocols are characterized by disparity. Ion-pairing (IP) reagents are commonly used in chromatographic applications, but their combination with SPE is less known. The aim of this study was to evaluate various SPE loading conditions, including the use of IP reagents, to improve the recoveries of nine selected peptide molecules. Control of pH and the use of IP reagents were found to be crucial to improve the enrichment of the peptides, especially cationic peptides, for which an up to ten-fold increase was observed. The practical potential of the presented theoretical findings were verified by employing IP-SPE for the development of an efficient extraction method for the doping relevant peptide Synacthen. The general proof of principle was obtained by analysis of excretion study urine samples and validation was performed with focus on the limit of detection (20 pg/ml) and recovery (37%).

Label-free liquid crystal biosensor for cecropin B detection

A label-free liquid crystal (LC) biosensor based on orientation changes of LC molecules was reported for the detection of cecropin B. The homeotropic-to-tilted alignment transition of LC molecules, induced by the specific binding event between cecropin B and anti-cecropin B antibody immobilized via glutaraldehyde, could result in obvious change of the optical appearance from a dark to a bright response and as a result, the detection limit of cecropin B was as low as 50 ng/mL. The average gray-scale intensities (GIs) of optical appearances were calculated to quantitatively analyse cecropin B concentrations. This study offers a simple, highly sensitive and specific, lable-free method for cecropin B detection.

Adsorption effects of the doping relevant peptides Insulin Lispro, Synachten, TB-500 and GHRP 5

The tendency of peptides to adsorb to surfaces can raise a concern in variety of analytical fields where the qualitative/quantitative measurement of low concentration analytes (ng/mL-pg/mL) is required. To demonstrate the importance of using the optimal glassware/plasticware, four doping relevant model peptides (GHRP 5, TB-500, Insulin Lispro, Synachten) were chosen and their recovery from various surfaces were evaluated. Our experiments showed that choosing expensive consumables with low-bind characteristics is not beneficial in all cases. A careful selection of the consumables based on the evaluation of the physico/chemical features of the peptide is recommended.

Immunoaffinity techniques coupled to mass spectrometry for the analysis of human peptide hormones: advances and applications

INTRODUCTION

The accurate and comprehensive determination of peptide hormones from biological fluids has represented a considerable challenge to analytical chemists for decades. Besides long-established bioanalytical ligand binding assays (or ELISA, RIA, etc.), more and more mass spectrometry-based methods have been developed recently for purposes commonly referred to as targeted proteomics. Eventually the combination of both, analyte extraction by immunoaffinity and subsequent detection by mass spectrometry, has shown to synergistically enhance the test methods' performance characteristics. Areas covered: The review provides an overview about the actual state of existing methods and applications concerning the analysis of endogenous peptide hormones. Here, special focus is on recent developments considering the extraction procedures with immobilized antibodies, the subsequent separation of target analytes, and their detection by mass spectrometry. Expert commentary: Key aspects of procedures aiming at the detection and/or quantification of peptidic analytes in biological matrices have experienced considerable improvements in the last decade, particularly in terms of the assays' sensitivity, the option of multiplexing target compounds, automatization, and high throughput operation. Despite these advances and progress as expected to be seen in the near future, immunoaffinity purification coupled to mass spectrometry is not yet a standard procedure in routine analysis compared to ELISA/RIA.

Analytical challenges in the detection of peptide hormones for anti-doping purposes

Although significant progress has been achieved during the past few years with the introduction of new assays and analytical methodologies, the detection and quantification of protein analytes, in particular of peptide hormones, continues to pose analytical challenges for the World Anti-Doping Agency-accredited anti-doping laboratories. In this article, the latest achievements in the application of MS-based methodologies and specific biochemical and immunological assays to detect some of the prohibited substances listed in section S2 of the World Anti-Doping Agency List of Prohibited Substances and Methods are reviewed. In addition, we look towards the future by focusing on some of the most promising analytical approaches under development for the detection of so-called ‘biomarkers of doping’.

OMICS-strategies and methods in the fight against doping

During the past decade OMICS-methods not only continued to have their impact on research strategies in life sciences and in particular molecular biology, but also started to be used for anti-doping control purposes. Research activities were mainly reasoned by the fact that several substances and methods, which were prohibited by the World Anti-Doping Agency (WADA), were or still are difficult to detect by direct methods. Transcriptomics, proteomics, and metabolomics in theory offer ideal platforms for the discovery of biomarkers for the indirect detection of the abuse of these substances and methods. Traditionally, the main focus of transcriptomics and proteomics projects has been on the prolonged detection of the misuse of human growth hormone (hGH), recombinant erythropoietin (rhEpo), and autologous blood transfusion. An additional benefit of the indirect or marker approach would also be that similarly acting substances might then be detected by a single method, without being forced to develop new direct detection methods for new but comparable prohibited substances (as has been the case, e.g. for the various forms of Epo analogs and biosimilars). While several non-OMICS-derived parameters for the indirect detection of doping are currently in use, for example the blood parameters of the hematological module of the athlete's biological passport, the outcome of most non-targeted OMICS-projects led to no direct application in routine doping control so far. The main reason is the inherent complexity of human transcriptomes, proteomes, and metabolomes and their inter-individual variability. The article reviews previous and recent research projects and their results and discusses future strategies for a more efficient application of OMICS-methods in doping control.

Analytical aspects in doping control: challenges and perspectives

Since the first anti-doping tests in the 1960s, the analytical aspects of the testing remain challenging. The evolution of the analytical process in doping control is discussed in this paper with a particular emphasis on separation techniques, such as gas chromatography and liquid chromatography. These approaches are improving in parallel with the requirements of increasing sensitivity and selectivity for detecting prohibited substances in biological samples from athletes. Moreover, fast analyses are mandatory to deal with the growing number of doping control samples and the short response time required during particular sport events. Recent developments in mass spectrometry and the expansion of accurate mass determination has improved anti-doping strategies with the possibility of using elemental composition and isotope patterns for structural identification. These techniques must be able to distinguish equivocally between negative and suspicious samples with no false-negative or false-positive results. Therefore, high degree of reliability must be reached for the identification of major metabolites corresponding to suspected analytes. Along with current trends in pharmaceutical industry the analysis of proteins and peptides remains an important issue in doping control. Sophisticated analytical tools are still mandatory to improve their distinction from endogenous analogs. Finally, indirect approaches will be discussed in the context of anti-doping, in which recent advances are aimed to examine the biological response of a doping agent in a holistic way.

Detection of His-tagged Long-R³-IGF-I in a black market product

OBJECTIVE

Performance-enhancing substances are illicitly used in elite or amateur sports and may be obtained from the black market due to a cheaper and easier availability. Although various studies have shown that black market products frequently do not contain the declared substances, enormous amounts of illegally produced and/or imported drugs are confiscated from athletes or at customs with alarming results concerning the outcome of the analyses of the ingredients. This case report describes the identification of His-tagged Long-R³-IGF-I, which is usually produced for biochemical studies, in an injection vial.

DESIGN

The ingredients were isolated by immunoaffinity purification and identified by nano-UPLC, high-resolution/high accuracy mass spectrometry of the intact and trypsinated substance and by an enzyme-linked immunosorbent assay.

RESULTS

(Tandem) mass spectra characterized the protein as Long-R³-IGF-I with a His₆-tag attached to the C-terminus by the linker amino acids Leu-Glu.

CONCLUSION

His-tags are commonly added to proteins during synthesis to allow a convenient and complete purification of the final product and His-tags are subsequently removed by specific enzymes when being attached to the N-terminus. The effects of His-tagged Long-R³-IGF-I in humans have not been elucidated or described and the product may rather be a by-product from biochemical studies than synthesized for injection purposes.