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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 -
Methods in Molecular Biology (Clifton,... 2019Microchip isotachophoresis (μITP) is a miniaturized version of conventional isotachophoresis (ITP) characterized by low sample and buffer consumption and reduced waste...
Microchip isotachophoresis (μITP) is a miniaturized version of conventional isotachophoresis (ITP) characterized by low sample and buffer consumption and reduced waste production. μITP with universal conductivity detection is suitable for quantitative analysis of relatively simplified samples that contain analyte(s) at relatively high concentration, e.g., pharmaceutical preparations. Here we describe in detail a principle of μITP in terms of reaching highly precise results. A practical use of μITP is shown on the analyses of various pharmaceutical preparations for content of major constituents including active pharmaceutical ingredients as well as pharmaceutical counterions. The pharmaceuticals are treated only minimally prior to the ITP run on a microchip with coupled channels and sample injection channel with 0.9 μL volume. Developed method is suitable for rapid (analysis time up to 10 min), precise (less than 1% RSD of analyte zone length), and accurate (recovery of 98-101%) determination of major pharmaceutical ingredients using a method of internal standard for data evaluation.
Topics: Acetylcysteine; Buserelin; Electric Conductivity; Electrophoresis, Microchip; Isotachophoresis; Microarray Analysis; Pharmaceutical Preparations
PubMed: 30488388
DOI: 10.1007/978-1-4939-8964-5_7 -
Journal of Pharmaceutical and... Feb 2021Thyroid hormones act on almost every tissue in the body to promote catabolism in cells and are important for regulating many biological processes. Accurate...
Thyroid hormones act on almost every tissue in the body to promote catabolism in cells and are important for regulating many biological processes. Accurate quantification of endogenous thyroid hormones has become essential for clinical and non-clinical applications in the development of new drugs according to the OECD Guideline (2018). However, there are difficulties in quantitative analysis of thyroid hormones because no analyte-free biological matrices are available for analysis of endogenous substances. In this study, surrogate matrix and surrogate analyte methods were compared and validated to quantify endogenous triiodothyronine (T) and thyroxine (T) in rat serum using LC-MS/MS. Separation of analytes was performed using an Xbridge™ C18 (2.1 × 50 mm, 2.5 μm) column. In the surrogate matrix, 3,3'5-triiodo- l-thyronine-C (cT) and l-thyroxine-C (cT) were used as the internal standard (IS), and in the surrogate analyte, l-3,3'-diiodothyronine-C (cT) was used as the IS. The mobile phases consisted of 0.1 % acetic acid in purified water (A) and 0.1 % acetic acid in acetonitrile (B). Both analytical methods were suitable for selectivity, matrix effect, carryover, lower limit of quantification, linearity, accuracy, precision, recovery, stability and parallelism. The surrogate matrix method was more accurate than using the surrogate analyte method, including evaluation of parallelism at low concentrations. Additionally, the surrogate matrix is cost-effective for T and T analysis in biological samples because it consists only of deionized water. However, surrogate analytes difficult to evaluate parallelism by obtaining response factors for mass spectrometric signal differences between the actual and surrogate analytes. Therefore, the results of this study indicate that it is more cost-effective to use the surrogate matrix method for endogenous thyroid hormone, T and T, analysis in biological samples.
Topics: Animals; Chromatography, Liquid; Rats; Reproducibility of Results; Tandem Mass Spectrometry; Thyroid Hormones; Thyroxine; Triiodothyronine
PubMed: 33383502
DOI: 10.1016/j.jpba.2020.113840 -
Materials Today. Bio Jun 2023Gold nanozymes (GNZs) have been widely used in biosensing and bioassay due to their interesting catalytic activities that enable the substitution of natural enzyme. This... (Review)
Review
Gold nanozymes (GNZs) have been widely used in biosensing and bioassay due to their interesting catalytic activities that enable the substitution of natural enzyme. This review explains different catalytic activities of GNZs that can be achieved by applying different modifications to their surface. The role of Gold nanoparticles (GNPs) in mimicking oxidoreductase, helicase, phosphatase were introduced. Moreover, the effect of surface properties and modifications on each catalytic activity was thoroughly discussed. The application of GNZs in biosensing and bioassay was classified in five categories based on the combination of the enzyme like activities and enhancing/inhibition of the catalytic activities in presence of the target analyte/s that is realized by proper surface modification engineering. These categories include catalytic activity enhancer, reversible catalytic activity inhibitor, binding selectivity enhancer, agglomeration base, and multienzyme like activity, which are explained and exemplified in this review. It also gives examples of those modifications that enable the application of GNZs for biosensing and bioassays.
PubMed: 37214551
DOI: 10.1016/j.mtbio.2023.100656 -
The Journal of Physical Chemistry... Aug 2023Nanoparticle-assisted nuclear magnetic resonance (NMR) chemosensing exploits monolayer-protected nanoparticles as supramolecular hosts to detect small molecules in...
Nanoparticle-assisted nuclear magnetic resonance (NMR) chemosensing exploits monolayer-protected nanoparticles as supramolecular hosts to detect small molecules in complex mixtures via nuclear Overhauser effect experiments with detection limits down to the micromolar range. Still, the structure-sensitivity relationships at the basis of such detection limits are little understood. In this work, we integrate NMR spectroscopy and atomistic molecular dynamics simulations to examine the covariates that affect the sensitivity of different NMR chemosensing experiments [saturation transfer difference (STD), water STD, and high-power water-mediated STD]. Our results show that the intensity of the observed signals correlates with the number and duration of the spin-spin interactions between the analytes and the nanoparticles and/or between the analytes and the nanoparticles' solvation molecules. In turn, these parameters depend on the location and dynamics of each analyte inside the monolayer. This insight will eventually facilitate the tailoring of experimental and computational setups to the analyte's chemistry, making NMR chemosensing an even more effective technique in practical use.
PubMed: 37498189
DOI: 10.1021/acs.jpclett.3c01005 -
Journal of Chromatography. B,... Sep 2014This review deals with chemical and technical challenges in the analysis of small-molecule metabolites involved in central carbon and energy metabolism via... (Review)
Review
This review deals with chemical and technical challenges in the analysis of small-molecule metabolites involved in central carbon and energy metabolism via liquid-chromatography mass-spectrometry (LC-MS). The covered analytes belong to the prominent pathways in biochemical carbon oxidation such as glycolysis or the tricarboxylic acid cycle and, for the most part, share unfavorable properties such as a high polarity, chemical instability or metal-affinity. The topic is introduced by selected examples on successful applications of metabolomics in the clinic. In the core part of the paper, the structural features of important analyte classes such as nucleotides, coenzyme A thioesters or carboxylic acids are linked to "problematic hotspots" along the analytical chain (sample preparation and-storage, separation and detection). We discuss these hotspots from a chemical point of view, covering issues such as analyte degradation or interactions with metals and other matrix components. Based on this understanding we propose solutions wherever available. A major notion derived from these considerations is that comprehensive carbon metabolomics inevitably requires multiple, complementary analytical approaches covering different chemical classes of metabolites.
Topics: Animals; Carbon; Chromatography, Liquid; Humans; Mass Spectrometry; Metabolomics
PubMed: 24326023
DOI: 10.1016/j.jchromb.2013.11.022 -
Soft Matter Nov 2023Nanoparticle aggregation is a driving principle of innovative materials and biosensing methodologies, improving transduction capabilities displayed by optical,...
Nanoparticle aggregation is a driving principle of innovative materials and biosensing methodologies, improving transduction capabilities displayed by optical, electrical or magnetic measurements. This aggregation can be driven by the biomolecular recognition between target biomolecules (analytes) and receptors bound onto nanoparticle surface. Despite theoretical advances on modelling the entropic interaction in similar systems, predictions of the fractal morphologies of the nanoclusters of bioconjugated nanoparticles are lacking. The morphology of resulting nanoclusters is sensitive to the location, size, flexibility, average number of receptors per particle , and the analyte-particle concentration ratio. Here we considered bioconjugated iron oxide nanoparticles (IONPs) where bonds are mediated by a divalent protein that binds two receptors attached onto different IONPs. We developed a protocol combining analytical expressions for receptors and linker distributions, and Brownian dynamics simulations for bond formation, and validated it against experiments. As more bonds become available (, by adding analytes), the aggregation deviates from the ideal Bethe's lattice scenario due to multivalence, loop formation, and steric hindrance. Generalizing Bethe's lattice theory with a (not-integer) effective functionality leads to analytical expressions for the cluster size distributions in excellent agreement with simulations. At high analyte concentration steric impediment imposes an accessible limit value to , which is bounded by < < . A transition to gel phase, is correctly captured by the derived theory. Our findings offer new insights into quantifying analyte amounts by assessing nanocluster size, and predicting nanoassembly morphologies accurately is a first step towards understanding variations of physical properties in clusters formed after biomolecular recognition.
Topics: Particle Size; Nanoparticles; Molecular Dynamics Simulation
PubMed: 37530392
DOI: 10.1039/d3sm00536d -
Current Pathobiology Reports 2018Liquid biopsy analyses based on circulating cell-free nucleic acids, circulating tumor cells or other diseased cells from organs, and exosomes or other microvesicles in... (Review)
Review
PURPOSE OF REVIEW
Liquid biopsy analyses based on circulating cell-free nucleic acids, circulating tumor cells or other diseased cells from organs, and exosomes or other microvesicles in blood offer new means for non-invasive diagnostic applications. The main goal of this review is to explain the importance of preserving whole blood specimens after blood draw for use as liquid biopsies, and to summarize preservation solutions that are currently available.
RECENT FINDINGS
Despite the great potential of liquid biopsies for diagnostics and disease management, besides non-invasive prenatal testing (NIPT), only a few liquid biopsy applications are fully implemented for routine in vitro diagnostic testing. One major barrier is the lack of standardized pre-analytical workflows, including the collection of consistent quality blood specimens and the generation of good-quality plasma samples therefrom. Broader use of liquid biopsies in clinical routine applications therefore requires improved pre-analytical procedures to enable high-quality specimens to obtain unbiased analyte profiles (DNA, RNA, proteins, etc.) as they are in the patient's body.
SUMMARY
A growing number of stabilizing reagents and dedicated blood collection tubes are available for the post-collection preservation of circulating cell-free DNA (ccfDNA) profiles in whole blood. In contrast, solutions for the preservation of circulating tumor cells (CTC) that enable both, enumeration and molecular analyses are rare. Solutions for extracellular vesicle (EV) populations, including exosomes, do not yet exist.
PubMed: 30595972
DOI: 10.1007/s40139-018-0180-z -
Clinica Chimica Acta; International... Nov 2018A transition ion ratio (TIR) is the ratio of one fragment over another from the same precursor and is frequently monitored in liquid chromatography-tandem mass...
BACKGROUND
A transition ion ratio (TIR) is the ratio of one fragment over another from the same precursor and is frequently monitored in liquid chromatography-tandem mass spectrometry (LC-MS/MS) assays for analyte identification. The Clinical and Laboratory Standards Institute (CLSI) C50-A guidelines give a static percent allowable TIR deviation based on the TIR level. Anecdotally, we observed failures of these rules for some of our LC-MS/MS assays. We determined what parameters may affect TIRs in a clinical setting and whether TIR variations may be analyte, matrix, instrument service, and/or concentration dependent.
METHODS
Data was collected from the validation and selected periods after implementation for urine benzodiazepines (7 analytes) and plasma azole antifungals (6 analytes). TIRs for the calibrators and quality control materials on a Thermo TSQ™ Quantum Ultra from July 2016 to February 2017 for benzodiazepines in urine and Thermo TSQ™ Vantage from May 2016 to Oct 2016 for azoles in serum were monitored.
RESULTS
The statistically significant day-to-day TIR shift ranged from 5.7 to 27.0% of the days studies for benzodiazepines and from 5.6 to 27.8% of the days studied for azoles excluding shifts caused by instrument services. Instrument service had significant impact on all benzodiazepines except oxazepam with p-values ranging from 1.79 × 10 to 1.53 × 10 and 4 of the 6 azoles (fluconazole, isavuconazole, voriconazole, and itraconazole) with (p from 7.89 × 10 to 1.98 × 10). Lorazepam, α-hydroxyalprazolam, and hydroxyitraconazole showed significant concentration dependent TIR variations.
CONCLUSIONS
TIR variations may be affected by instrument services, and can be concentration and analyte dependent. Instead of using a static percent deviation rule, establishment of TIR variation criteria for each analyte during test development and validation may provide a more useful tool for analyte identification.
Topics: Antifungal Agents; Azoles; Benzodiazepines; Chemistry Techniques, Analytical; Chromatography, Liquid; Clinical Laboratory Techniques; Humans; Ions; Tandem Mass Spectrometry
PubMed: 30098951
DOI: 10.1016/j.cca.2018.08.009 -
Journal of Analytical Methods in... 2022The use of doping by athletes to improve performance is prohibited. Therefore, doping testing is an important step to ensure fairness in sports. Doping is gradually... (Review)
Review
The use of doping by athletes to improve performance is prohibited. Therefore, doping testing is an important step to ensure fairness in sports. Doping is gradually metabolized in the body and is therefore difficult to detect immediately by a common method. At the same time, the emergence of new doping agents poses a challenge for highly sensitive detection. Electrochemical sensors are a fast, highly sensitive, and inexpensive analytical detection technology. It provides qualitative and quantitative determination of analytes by altering the electrochemical signal of the analyte or probe at the electrode. In this min-review, we summarized the different electrochemical sensing strategies for sterol doping detection. Some of the representative papers were interpreted in detail. In addition, we compare different sensing strategies.
PubMed: 36117750
DOI: 10.1155/2022/3394079