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Journal of Pharmaceutical and... Jan 2021Binding between cyclodextrin (CD) cavity and guest molecule in Reversed Phase High-Performance Liquid Chromatography (RP-HPLC) is dynamic process. In general, increasing...
Binding between cyclodextrin (CD) cavity and guest molecule in Reversed Phase High-Performance Liquid Chromatography (RP-HPLC) is dynamic process. In general, increasing CD concentration is inducing inclusion complex formation, leading to reduction of analyte's retention time. Consequently, the shortness in retention time is a measure of complex stability in HPLC. However, under certain experimental conditions, the retention of some analytes could be prolonged even when concentration of CD in the mobile phase is increased. In order to reveal the cause of this unexpected retention behavior, the present study was carried on. The model mixture consisted of risperidone, olanzapine and their related impurities, while β-CD was selected among CDs, as in the previous study. In order to achieve fast equilibrium between free analyte and β-CD-analyte complex, β-CD was not added to the mobile phase, but only to the sample. Detection was performed with Corona Charged Aerosol Detector (CAD), suitable for non-chromophoric β-CD. When analyzing olanzapine impurity B-β-CD sample, three peaks were detected, namely free β-CD, β-CD-analyte complex and free analyte. The complex stability constant was calculated employing a modification of the Benesi-Hildebrandt equation and CAD has proven to be useful in complex stability constants assessment if retention of free analyte and β-CD-analyte complex is distinguished. For all other analytes only two peaks could be detected, because free analyte and formed complex are eluting at the same retention time. Under such circumstances, the authors proposed the methodology for calculating stability constants and confirmed its applicability to studied model mixture.
Topics: Aerosols; Chromatography, High Pressure Liquid; Chromatography, Reverse-Phase; Risperidone; beta-Cyclodextrins
PubMed: 33137595
DOI: 10.1016/j.jpba.2020.113711 -
Biosensors Mar 2024Covalent organic frameworks (COFs) are porous crystals that have high designability and great potential in designing, encapsulating, and immobilizing nanozymes. COF... (Review)
Review
Covalent organic frameworks (COFs) are porous crystals that have high designability and great potential in designing, encapsulating, and immobilizing nanozymes. COF nanozymes have also attracted extensive attention in analyte sensing and detection because of their abundant active sites, high enzyme-carrying capacity, and significantly improved stability. In this paper, we classify COF nanozymes into three types and review their characteristics and advantages. Then, the synthesis methods of these COF nanozymes are introduced, and their performances are compared in a list. Finally, the applications of COF nanozymes in environmental analysis, food analysis, medicine analysis, disease diagnosis, and treatment are reviewed. Furthermore, we also discuss the application prospects of COF nanozymes and the challenges they face.
Topics: Metal-Organic Frameworks; Biosensing Techniques; Nanostructures; Chemistry, Analytic; Food Analysis; Chemistry Techniques, Analytical
PubMed: 38667156
DOI: 10.3390/bios14040163 -
Sensors (Basel, Switzerland) May 2016Enzyme-based chemical biosensors are based on biological recognition. In order to operate, the enzymes must be available to catalyze a specific biochemical reaction and... (Review)
Review
Enzyme-based chemical biosensors are based on biological recognition. In order to operate, the enzymes must be available to catalyze a specific biochemical reaction and be stable under the normal operating conditions of the biosensor. Design of biosensors is based on knowledge about the target analyte, as well as the complexity of the matrix in which the analyte has to be quantified. This article reviews the problems resulting from the interaction of enzyme-based amperometric biosensors with complex biological matrices containing the target analyte(s). One of the most challenging disadvantages of amperometric enzyme-based biosensor detection is signal reduction from fouling agents and interference from chemicals present in the sample matrix. This article, therefore, investigates the principles of functioning of enzymatic biosensors, their analytical performance over time and the strategies used to optimize their performance. Moreover, the composition of biological fluids as a function of their interaction with biosensing will be presented.
Topics: Biosensing Techniques; Body Fluids; Enzymes
PubMed: 27249001
DOI: 10.3390/s16060780 -
Talanta Apr 2018The research and applications of immobilized enzyme reactors (IMERs) have become more and more widespread due to the numerous advantages like reusability, easy handling,... (Review)
Review
The research and applications of immobilized enzyme reactors (IMERs) have become more and more widespread due to the numerous advantages like reusability, easy handling, prolonged lifetime, easy separation from products and substrate specificity. The miniaturized form of these reactors (microchip IMERs) received outstanding attention due to their special features and advantages over the traditional, larger analytical systems. Large specific surface is essential for the efficient operation of the microreactors, thus these devices include one of the several types of porous solid supports, but in this work only the particle based microchip IMERs are reviewed. A very large variety of micro- or nanoparticles (beads) have been used in the microchip IMERs, however, incorporating these particles into microchips is still a challenge, because the common procedures used for the preparation of chromatographic columns are not well applicable at the microscopic level. Many detection systems were applied with microchip IMERs using on-chip or off-chip arrangement. The combination of microchip IMERs with mass spectrometry is particularly popular, because in these systems high-throughput analysis can be achieved by which the proteomic studies can be largely accelerated. In most chip IMER-MS systems, the chips are used for sample pretreatment including analyte (protein) digestion, preconcentration of analyte, removal of matrix materials. Additional applications of the IMERs - like the rapid protein digestion with proteolytic enzymes, the transformation of analytes to a more easily or more sensitively measurable form (detection signal amplification) and the design of microarrays/biosensors to analyze antigens based on specific interactions in immunoanalytical studies - are also reviewed.
Topics: Animals; Enzymes, Immobilized; Equipment Design; Humans; Lab-On-A-Chip Devices; Microspheres; Nanoparticles; Proteolysis
PubMed: 29332803
DOI: 10.1016/j.talanta.2017.12.043 -
Clinica Chimica Acta; International... Aug 2020Discovery of new protein biomarker candidates has become a major research goal in the areas of clinical chemistry, analytical chemistry, and biomedicine. These important... (Review)
Review
Discovery of new protein biomarker candidates has become a major research goal in the areas of clinical chemistry, analytical chemistry, and biomedicine. These important species constitute the molecular target when it comes to diagnosis, prognosis, and further monitoring of disease. However, their analysis requires powerful, selective and high-throughput sample preparation and product (analyte) characterisation approaches. In general, manual sample processing is tedious, complex and time-consuming, especially when large numbers of samples have to be processed (e.g., in clinical studies). Automation via microtiter-plate platforms involving robotics has brought improvements in high-throughput performance while comparable or even better precisions and repeatability (intra-day, inter-day) were achieved. At the same time, waste production and exposure of laboratory personnel to hazards were reduced. In comprehensive protein analysis workflows (e.g., liquid chromatography-tandem mass spectrometry analysis), sample preparation is an unavoidable step. This review surveys the recent achievements in automation of bottom-up and top-down protein and/or proteomics approaches. Emphasis is put on high-end multi-well plate robotic platforms developed for clinical analysis and other biomedical applications. The literature from 2013 to date has been covered.
Topics: Analytic Sample Preparation Methods; Chemistry Techniques, Analytical; Humans; Proteins; Robotics
PubMed: 32305536
DOI: 10.1016/j.cca.2020.04.015 -
Chemistry (Weinheim An Der Bergstrasse,... Apr 2024The detection of analytes with small molecular probes is crucial for the analysis and understanding of chemical, medicinal, environmental and biological situations as...
The detection of analytes with small molecular probes is crucial for the analysis and understanding of chemical, medicinal, environmental and biological situations as well as processes. Classic detection approaches rely on the concept of molecular recognition and bond formation reactions. Bond breakage reactions have been less explored in similar contexts. This concept article introduces metal-salen and metal-imine complexes as "covalent-disassembly"-based (DB)-probes for detecting polyoxophosphates, thiols, amino acids, HCN and changes in pH. It discusses the roles, importance and combinations of structurally functionalized molecular building blocks in the construction of DB-probes. Applications of optimized DB-probes for analyte detection in live cells and foodstuff are also discussed. Furthermore, the mechanism of the disassembly of a Fe(III)-salen probe upon pyrophosphate binding is presented. Extraordinary selectivity for this analyte was achieved by a multistep disassembly sequence including an unprecedented structural change of the metal complex (i. e. "induced-fit" principle). Design principles of probes for sensing applications following the "covalent-disassembly" approach are summarized, which will help improving current systems, but will also facilitate the development of new DB-probes for challenging analytic targets.
Topics: Ferric Compounds; Metals; Ethylenediamines; Coordination Complexes
PubMed: 38179824
DOI: 10.1002/chem.202302705 -
Bioanalysis Feb 2022Analyzing unstable small molecule drugs and metabolites in blood continues to be challenging for bioanalysis. Although scientific countermeasures such as immediate... (Review)
Review
Analyzing unstable small molecule drugs and metabolites in blood continues to be challenging for bioanalysis. Although scientific countermeasures such as immediate cooling, immediate freezing, addition of enzyme inhibitors, pH adjustment, dried blood spot or derivatization have been developed, selecting the best practices has become an issue in the pharmaceutical industry as the number of drugs with such problems is increasing, even for generic drugs. In this study, we conducted a comprehensive literature review and a questionnaire survey to determine a suitable practice for evaluating instability and implementing countermeasures. Three areas of focus, matrix selection, effect of hemolysis and selection of esterase inhibitors, are discussed.
Topics: Biological Assay; Chemistry, Analytic; Humans; Japan; Surveys and Questionnaires
PubMed: 34894755
DOI: 10.4155/bio-2021-0229 -
Analytica Chimica Acta Jan 2023Noble metal nanoparticles (MNPs), have represented the keystone of a plethora of (bio)sensing analytical strategies because of their unique physicochemical features,... (Review)
Review
Noble metal nanoparticles (MNPs), have represented the keystone of a plethora of (bio)sensing analytical strategies because of their unique physicochemical features, becoming unique tools in the analytical scenario; in particular, MNPs localized surface plasmon resonance (LSPR) offers infinite analytical possibilities. In this work, the scaling-up from colloidal MNPs to their integration in solid substrates is overviewed, and the relative sensing and biosensing optical strategies based on LSPR changes are systematically treated in accordance with the supporting substrate employed. Recent literature and key papers reporting MNPs integration into solid substrates are considered, paying particular attention to the MNPs-based event into/onto the solid support and the related plasmonic change used as analytical signal. The review is organized in sections according to the solid support nature (glass, polymers, cellulose) and the papers are discussed according to the sensing strategy. The strategies have been classified in MNPs synthesis, growth, etching, displacement/aggregation directly or indirectly mediated by the analyte(s); only works that rely on plasmonic-transduction principles are taken into account, MNPs used as catalysts or in lateral flow systems are not considered. The review demonstrates that MNPs decorated/integrated substrates are now mature analytical tools, able to overcome the limitations of MNPs colloidal suspensions; this results in new analytical opportunities, particularly the realization of integrated systems, lab-on-chip/lab-on-strip and flexible devices, paving the way for a new generation of plasmonic (bio)sensors for point-of-need applications.
Topics: Nanostructures; Surface Plasmon Resonance; Metal Nanoparticles; Cellulose; Polymers
PubMed: 36442936
DOI: 10.1016/j.aca.2022.340594 -
Current Issues in Molecular Biology Oct 2023An immunoassay is an analytical test method in which analyte quantitation is based on signal responses generated as a consequence of an antibody-antigen interaction.... (Review)
Review
An immunoassay is an analytical test method in which analyte quantitation is based on signal responses generated as a consequence of an antibody-antigen interaction. They are the method of choice for the measurement of a large panel of diagnostic markers. Not only are they fully automated, allowing for a short turnaround time and high throughput, but offer high sensitivity and specificity with low limits of detection for a wide range of analytes. Many immunoassay manufacturers exploit the extremely high affinity of biotin for streptavidin in their assay design architectures as a means to immobilize and detect analytes of interest. The biotin-(strept)avidin system is, however, vulnerable to interference with high levels of supplemental biotin that may cause elevated or suppressed test results. Since this system is heavily applied in clinical diagnostics, biotin interference has become a serious concern, prompting the FDA to issue a safety report alerting healthcare workers and the public about the potential harm of ingesting high levels of supplemental biotin contributing toward erroneous diagnostic test results. This review includes a general background and historical prospective of immunoassays with a focus on the biotin-streptavidin system, interferences within the system, and what mitigations are applied to minimize false diagnostic results.
PubMed: 37998726
DOI: 10.3390/cimb45110549 -
Bioanalysis 2015Specific guidelines on bioanalytical method validation for drug development support are recommended by regulatory agencies. Regarding stability assessment, US FDA states... (Review)
Review
Specific guidelines on bioanalytical method validation for drug development support are recommended by regulatory agencies. Regarding stability assessment, US FDA states that 'Stability procedures should evaluate the stability of the analytes during sample collection and handling, after long-term (frozen at the intended storage temperature) and short-term (bench-top, room temperature) storage, and after going through freeze and thaw cycles and the analytical process'. Additional regulatory considerations are discussed including topics such as analyte and reagent stability. This article reviews the regulatory requirements as issued by the USA (FDA), Europe (EMA) and Japan (MHLW), for stability studies where bioanalytical methods are used to support drug development programs and summarizes the current industry standard for conducting stability studies when utilizing ligand-binding assays.
Topics: Chemistry Techniques, Analytical; Drug Discovery; Drug Stability; Europe; Humans; Indicators and Reagents; Japan; Legislation, Drug; Pharmaceutical Preparations; United States; United States Food and Drug Administration
PubMed: 26110710
DOI: 10.4155/bio.15.52