Development Of Analytical Methods Research Articles

Two Steps Non-Enzymatic Synthesis of Molnupiravir, which is Free from Mutagenic Impurity and Analytical Method Development for Estimation of Genotoxic Impurity (Hydroxylamine Hydrochloride Content) by using RP-HPLC Technique

Genotoxic impurity free Molnupiravir was synthesised by a novel and an elegant non-enzymatic method, which is simple operationally and ecologically. The genotoxic raw material, Hydroxylamine, was used in the initial stages of synthesis to get the mutagenic impurity free Molnupiravir. A new and sensitive HPLC method was developed and validated for the determination of hydroxylamine in Molnupiravir drug substance according to ICH guidelines. The HPLC method was developed and optimized on Zorbax SB C18 150×4.6mm, 3.5µm column with oven temperature maintained at 40°C. 1.0 mL of Orthophosphoric acid in 1000 mL water was selected as mobile phase in isocratic reverse phase mode. Chromatographic parameters are flow rate: 0.8 ml/min, wavelength detection: 252 nm, injection volume: 10µl and run time: 20 min. Based on the validation data; the method was found to be specific, sensitive, accurate and precise. This method can be used as a good quality control tool for quantification of hydroxylamine at the low level. The experimental data was deliberated in detail in this research paper.

Automated crack extension measurement method for fracture and fatigue analysis using digital image correlation

A novel Automated Crack Extension Measurement (ACEM) method based on combining decorrelation in strain field and a threshold near maximum of full-field strain obtained from digital image correlation, is developed in this work. A manual method for measuring crack extension from images of the specimen surface and ImageJ, was utilized to validate the accuracy of the proposed method. Initially, ACEM method was validated for crack extension under mode-I fracture of single edge notch specimens with different initial notch sizes. A satisfactory agreement was obtained from this analysis along with limits on the different parameter values used in ACEM. The method was then applied to low-cycle fatigue specimens with different initial notch lengths. Comparison of crack extension between ACEM and manual method reveals satisfactory agreement reinforcing the fidelity of the developed method for fracture and fatigue analysis. Fracture resistance and fatigue crack growth rate curves were also obtained for the different specimens.

Development and Validation of Analytical Method for Simultaneous Estimation of Mometasone Furoate Topical Formulation by HPLC-DAD

Mometsone furoate is a corticosteroid (glucocorticoid) having an anti-inflammatory activity. Corticosteroids showed a wide range of effects on various cell types such as mast cells, eosinoplills, neutrophills, macrophages, and lymphocytes.

Estimating Flow Direction of Circle of Willis Using Dynamic Arterial Spin-Labeling MR Angiography.

The circle of Willis (COW) is a crucial mechanism for cerebral collateral circulation. This proof-of-concept study aims to develop and assess an analysis method to characterize the hemodynamics of the arterial segments in the COW by using arterial spin-labeling (ASL) based non-contrast-enhanced dynamic MR angiography (dMRA). The developed analysis method uses a graph model, bootstrap strategy, and ensemble learning methodologies to determine the time curve shift from ASL dMRA to estimate the flow direction within the COW. The performance of the method was assessed on 52 subjects, by using the flow direction, either antegrade or retrograde, derived from 3D phase-contrast MR imaging as the reference. A total of 340 arterial segments in the COW were evaluated, among which 30 (8.8%) had retrograde flow according to 3D phase-contrast MRI. The ASL dMRA-based flow direction estimation has an accuracy, sensitivity, and specificity of 95.47%, 80%, and 96.34%, respectively. Using ASL dMRA and the developed image analysis method to estimate the flow direction in COW is feasible. This study provides a new method to assess the hemodynamics of the COW, which could be useful for the diagnosis and study of cerebrovascular diseases.

Solutions to the Landau–Lifshitz–Gilbert equation in the frequency space: Discretization schemes for the dynamic-matrix approach

The dynamic matrix method addresses the Landau–Lifshitz–Gilbert (LLG) equation in the frequency domain by transforming it into an eigenproblem. Subsequent numerical solutions are derived from the eigenvalues and eigenvectors of the dynamic matrix. In this work we explore discretization methods needed to obtain a matrix representation of the dynamic operator, a fundamental counterpart of the dynamic matrix. Our approach opens a new set of linear algebra tools for the dynamic matrix method and expose the approximations and limitations intrinsic to it. Moreover, our discretization algorithms can be applied to various discretization schemes, extending beyond micromagnetism problems. We present some application examples, including a technique to obtain the dynamic matrix directly from the magnetic free energy function of an ensemble of macrospins, and an algorithmic method to calculate numerical micromagnetic kernels, including plane wave kernels. We also show how to exploit symmetries and reduce the numerical size of micromagnetic dynamic-matrix problems by a change of basis. This procedure significantly reduces the size of the dynamic matrix by several orders of magnitude while maintaining high numerical precision. Additionally, we calculate analytical approximations for the dispersion relations in magnonic crystals. This work contributes to the understanding of the current magnetization dynamics methods, and could help the development and formulations of novel analytical and numerical methods for solving the LLG equation within the frequency domain.

Priority Competencies for Designated Education Officers in the Veterans Health Administration.

Designated Education Officers (DEOs) at Veteran Health Administration (VHA) hospitals are senior educational leaders tasked with oversight of all clinical training at a particular facility. They prioritize dozens of tasks and responsibilities each day, from educational policy and strategy to staff management, financial planning, onboarding of trainees, and facility planning and management. Clarifying priority competencies for the role can help executives recruit, appoint, and evaluate capable personnel and promote effective, efficient performance. Using a federally developed method of competency analysis, researchers consulted a panel of subject-matter experts to identify priority competencies for DEOs, using data from a 2013 study that operationalizes competencies for more than 200 federal jobs. The research identified 25 primary competencies within 6 leadership domains. Five of the primary competencies cut across all leadership domains. Veteran Health Administration subject-matter experts in educational leadership say the identified competencies are urgently needed, critical for effective leadership, and valuable for distinguishing superior DEO performance. The competencies are relevant to VHA and perhaps other senior academic leaders who develop health professions education programs, oversee clinical training, and manage educational change. In military training facilities, attending to these competencies can help Designated Institutional Officials responsible for graduate medical education become more credible partners to other hospital leaders and contribute to becoming a high reliability organization. Executives identifying, recruiting, and appointing VHA DEOs and Designated Institutional Officials at military training facilities should consider these competencies when assessing candidates.

Selective and Sensitive MIP-Based Electrochemical Sensor for the Analytical Determination of Lanreotide

Lanreotide (LAN) is an analog of somatostatin used to treat acromegaly and neuroendocrine tumors. Considering drug toxicity and the lack of sensitive techniques in drug analysis, the development of sensitive analytical methods is of great importance. During this research, a molecular imprinted polymer (MIP) based film [P(HEMA-MAGA)@MIP/GCE] was prepared by photopolymerization technique for electrochemical determination of LAN for the first time. N-methacryloyl-L-glutamic acid (MAGA) and hydroxyethyl methacrylate (HEMA) were used as functional and basic monomers, respectively. The surface alterations were investigated using scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) and the chemical composition of the MIP-based sensor. Theelectrochemical characterization of the modifiedelectrodes was assessed using electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). Using differential pulse voltammetry (DPV) in standard solution and spiked serum sample of LAN, the linear response range for LAN was obtained as 1.0x10 − 14 M – 1.0x10 − 13 M. The limit of detection (LOD) values were 1.76x10 − 15 M and 1.82x10 − 15 M in water and commercial human serum, respectively. The limit of quantitation(LOQ) values for these were 5.85x10 − 15 M and 6.07x10 − 15 M, respectively. The P(HEMA-MAGA)@MIP/GCE sensor also showed excellent recovery in pharmaceutical preparation and commercial human serum form with of 99.37 % and 99.27 %, respectively, with a good RSD value (0.51–0.73), confirming the accuracy and precision of the sensor. As a control, the non-imprinted polymer (NIP) was also prepared to serve in the same way but without the template. The selectivity experiments were conducted using somatostatin (SOM) and octreotide (OC) as potential competitors to demonstrate the selectivity of the proposed sensor against LAN molecules.

A Comprehensive Review on Advantages of Ultra Performance Liquid Chromatography (UPLC) for Analytical Method Development, Validation, and Stability Studies

Ultra Performance Liquid Chromatography (UPLC) represents a paradigm shift in analytical separation science, offering enhanced speed, sensitivity, and resolution while retaining the foundational principles of traditional liquid chromatography. This comprehensive review explores the principles, instrumentation, advantages, and applications of UPLC in analytical method development, validation, and stability studies, with a focus on pharmaceutical analysis. UPLC leverages finer particles and intensified flow rates to achieve unprecedented performance gains, facilitating rapid and precise separations without compromising analytical rigor. The discussion delves into the intricate instrumentation involved, including sample injection, column selection, and detector operation, highlighting the critical role of each component in ensuring optimal analytical performance. Advantages of UPLC include drastically reduced run times, streamlined method optimization, and increased sample throughput, while limitations such as higher back pressures and limited column regenerability are also discussed. Furthermore, the review outlines the diverse applications of UPLC across pharmaceutical, environmental, food and beverage, clinical, forensic, bioanalytical, and polymer analysis domains, underscoring its versatility and significance in advancing research, development, and quality control in various industries. In summary, UPLC represents a transformative tool in analytical chemistry, offering unparalleled capabilities for expedited and accurate analysis of complex sample matrices, ultimately driving innovation and scientific progress. Key Words: Ultra Performance Liquid Chromatography (UPLC), analytical method development, validation, stability studies, pharmaceutical analysis, instrumentation, advantages, applications, sample injection, column chemistry, detector technology, back pressures, method optimization, sample throughput, environmental analysis, food and beverage analysis, clinical diagnostics, forensic analysis, bioanalytical research, polymer analysis, analytical chemistry.

Rapid and reliable quantification of urinary malondialdehyde by HILIC-MS/MS: A derivatization-free breakthrough approach

BackgroundThe development of fast analytical methods is crucial for the research, discovery, and confirmation of crucial biomarkers. Furthermore, the implementation of fast analytical strategies contributes to efficient and time-effective procedures. In this sense, analysis of malondialdehyde (MDA) has become an important tool for understanding the role of oxidative stress in various diseases and for evaluating the efficacy of therapeutic interventions. ResultsA rapid and robust liquid chromatography tandem mass spectrometry method (HPLC-MS/MS) has been developed to determine endogenous amounts of malondialdehyde (MDA) in human urine without any associated derivatization reaction. MDA was separated in 4 min through a Urea-HILIC column and was analyzed using a triple quadrupole mass spectrometer in negative electrospray ionization mode. With a 50-fold dilution as the only sample pretreatment after alkaline hydrolysis, no matrix effect was present, which allowed for a fast and simple quantification by means of an external standard calibration with a limit of detection of 0.20 ng mL−1. The whole methodology was validated by analyzing unspiked and spiked urine samples from ten healthy individuals and comparing with the results obtained by the standard addition method. MDA was detected in all cases, with natural concentrations varying from 0.11 ± 0.03 to 0.31 ± 0.03 mg g−1 creatinine. Accuracies were found to be satisfactory, ranging from 95 % to 101 %. The proposed method also exhibited good repeatability and reproducibility (RSD<15 %) for four quality control levels. SignificanceThe main significance of this method is the avoidance of a derivatization reaction for the determination of urinary MDA, this constituting a step forward when compared with previous literature. This breakthrough not only streamlines time analysis to less than 5 min per sample but also results in a more robust procedure. Consequently, the method here developed could be applied to subsequent future research involving the determination of MDA as a lipid peroxidation biomarker, where simple, rapid, and reliable methods could represent a significant improvement.

Analytical Method Development for Authentication of Alpinia galanga Rhizome Based on Phenylpropanoid Markers by RP-HPLC-UV

Analytical Method Development for Authentication of Alpinia galanga Rhizome Based on Phenylpropanoid Markers by RP-HPLC-UV

Analytical Method Development and Dermal Absorption of 4-Amino-3-Nitrophenol (4A3NP), a Hair Dye Ingredient under the Oxidative or Non-Oxidative Condition.

The chemical 4-amino-3-nitrophenol (4A3NP) is classified as an amino nitrophenol and is primarily utilized as an ingredient in hair dye colorants. In Korea and Europe, it is exclusively used in non-oxidative or oxidative hair dye formulations, with maximum allowable concentrations of 1% and 1.5%, respectively. Despite this widespread use, risk assessment of 4A3NP has not been completed due to the lack of proper dermal absorption data. Therefore, in this study, both the analytical method validation and in vitro dermal absorption study of 4A3NP were conducted following the guidelines provided by the Korea Ministry of Food and Drug Safety (MFDS). Before proceeding with the dermal absorption study, analytical methods were developed for the quantitation of 4A3NP through multiple reaction monitoring (MRM) via liquid chromatography-mass spectrometry (LC-MS) in various matrices, including swab wash (WASH), stratum corneum (SC), skin (SKIN, comprising the dermis and epidermis), and receptor fluid (RF). These developed methods demonstrated excellent linearity (R2 = 0.9962-0.9993), accuracy (93.5-111.73%), and precision (1.7-14.46%) in accordance with the validation guidelines.The dermal absorption of 4A3NP was determined using Franz diffusion cells with mini-pig skin as the barrier. Under both non-oxidative and oxidative (6% hydrogen peroxide (H2O2): water, 1:1) hair dye conditions, 1% and 1.5% concentrations of 4A3NP were applied to the skin at a rate of 10 μL/cm2, respectively. The total dermal absorption rates of 4A3NP under non-oxidative (1%) and oxidative (1.5%) conditions were determined to be 5.62 ± 2.19% (5.62 ± 2.19 μg/cm2) and 2.83 ± 1.48% (4.24 ± 2.21 μg/cm2), respectively.

Quantitative analysis of oxygen heterocyclic compounds using liquid chromatography coupled to tandem mass spectrometry, method development and environmental assessment

The latest trends in the field of laboratory method development concern the validation of fast procedures, and the safety of the operator and environment. The present research is focused on the development of fast and environmentally-friendly analytical method of liquid chromatography-triple quadrupole mass spectrometry for the determination of oxygen heterocyclic compounds in Citrus-flavored products. To the best of the authors’ knowledge, this is the first approach for the characterization of thirty-six oxygen heterocyclic compounds in less than four minutes using water/ethanol as mobile phase. Molecules were characterized in Citrus essential oils and beverages. Figures of merit determined were linearity, precision, limits of detection and quantification. The method was compared in terms of greenness with our two methodologies previously published for analysis of oxygen heterocyclic compounds. The analytical greenness metric approach and the “RGB model” were used. According to these approaches, the method proposed here is faster, safer and more eco-friendly.

Analytical method development and dermal absorption of gallic acid, a hair dye ingredient.

Gallic acid (GA) is a phenolic compound known as 3,4,5-trihydroxybenzoic acid. GA is used as a hair dye ingredient. It is limited to be below 4.0% in Korea. Dermal absorption rate of GA has not been reported yet. In this study, an analytical method for GA was developed and validated using high-performance liquid chromatography (HPLC) in various matrices of swab, stratum corneum (SC), skin (dermis + epidermis), and receptor fluid (RF). HPLC analysis showed acceptable linearity (r2 = 0.999-0.9998), accuracy (90.3-112.8%), and precision (0.7-13.6%) in accordance with validation guidelines by Korea Ministry of Food and Drug Safety (MFDS). The dermal absorption rate of GA was determined using Franz diffuse cells. GA (4.0%) was applied to mini pig skin of 10μl/cm2. After 30min application, the GA was wiped out and receptor fluid sampling was continued until 24h. After 24h, skin was wiped off with swab and SC was collected using tape stripping. All samples were extracted with ethanol and analyzed using the validated method. The total dermal absorption rate of GA was determined to be 2.6 ± 1.3% (24h).

Current problems in the field of structure, properties of minerals and methods of their investigation

The main goal of research into the structure and properties of minerals, as well as their crystal chemistry and physics, consists in obtaining fundamental information about the actual atomic and electronic structure of mineral objects and physical regularities of their transformations under the influence of external factors (temperature, pressure, radiation, and environmental chemistry). Such information forms the basis for mineral typification and restoration of mineral crystallization conditions and their evolution in a certain geological situation. This information is widely used in petrogenetic and geochronological constructions. Such studies are also relevant to the development of nature-like technologies for obtaining new promising functional materials. Knowledge of the structure, crystal chemistry, and physics of minerals, typomorphism of their spectroscopic properties, as well as the development of analytical techniques and methods for the synthesis of mineral-like materials are of particular significance. This thematic issue of the Lithosphere journal aims to review of these problems in the context of the materials reported at the XIII All-Russian Scientific Conference “Minerals: Structure, Properties, Research Methods” held in 2023 at the Institute of Geology and Geochemistry of the Ural Branch of the Russian Academy of Sciences in Yekaterinburg.

Resolving the vicinity of supermassive black holes with gravitational microlensing

ABSTRACT Upcoming wide-field surveys will discover thousands of new strongly lensed quasars which will be monitored with unprecedented cadence by the Legacy Survey of Space and Time (LSST). Many of these quasars will undergo caustic-crossing events over the 10-yr LSST survey, during which the quasar’s inner accretion disc crosses a caustic feature produced by an ensemble of microlenses. Such caustic-crossing events offer the unique opportunity to probe the vicinity of the central supermassive black hole, especially when combined with high cadence, multi-instrument follow-up triggered by LSST monitoring. To simulate the high-cadence optical monitoring of caustic-crossing events, we use relativistic accretion disc models which leads to strong asymmetric features. We develop analysis methods to measure the innermost stable circular orbit (ISCO) crossing time of isolated caustic-crossing events and benchmark their performance on our simulations. We also use our simulations to train a convolutional neural network (CNN) to infer the black hole mass, inclination angle, and impact angle directly from these light curves. As a pilot application of our methods, we used archival caustic-crossings of QSO 2237+0305 to estimate the black hole mass and inclination angle. From these data, two of these methods called the second derivative and wavelet methods measure an ISCO crossing time of 48.5 and 49.5 d, corresponding to a Kerr black hole mass of MBH = (1.5 ± 1.2) × 109 and (1.5 ± 1.3) × 109 M⊙, respectively. The CNN inferred log10(MBH/M⊙) = 8.35 ± 0.30 when trained on Schwarzschild black hole simulations, and a moderate inclination of i = 45 ± 23°. These measurements are found to be consistent with previous estimates.

An innovative single-cell approach for phenotyping and functional genotyping of CAR NK cells

BackgroundTo accelerate the translation of novel immunotherapeutic treatment approaches, the development of analytic methods to assess their efficacy at early in vitro stages is necessary. Using a droplet-based microfluidic platform,...

Analytical method development and validation of prasugrel hydrochloride in bulk and its pharmaceutical formulation using the GC-MS, HPLC method

The present work reports rapid, sensitive and specific methods for determination of Prasugrel and its impurities by gas chromatography with mass spectrometry and high-performance liquid chromatography. The proposed method presented excellent intraday precision (% RSD &lt; 1), and accuracy 99.23 to 100.40% and 99.48 to 100.81% for Prasugrel and 2-bromo-1-cyclopropyl-2-(2-fluorophenyl) ethanone. Further the linearity of Prasugrel correlation coefficient is &gt;0.9994 and for bromo impurity correlation coefficient is &gt; 0.9993. The estimated limits of detection (LOD) and quantification (LOQ) for Prasugrel, 1-bromo-1-(2-fluorophenyl) propan-2-one ranged from 0.990 to 2.586 μg/mL, and 2.999 to 7.837 μg/mL respectively. The results demonstrated that the method should be regarded as a reliable alternative to the simultaneous determination of Prasugrel and its impurities. The EI mass spectrum of Prasugrel, fluoro, bromo, methyl bromo and dibromo impurities were characterized by [M + H]+ at 409, 189, 257, 231 and 311. The methods were validated according to ICH guideline.

Procjena utjecaja matriksa na kvantifikaciju lipofilnih toksina u plodovima mora

Phycotoxin accumulation in seafood can cause human intoxication and significant economic losses in seafood-producing areas. To protect consumer safety, maximum permitted levels in bivalve molluscs have been set, with appropriate analytical methods for their determination and quantification. The reference method for lipophilic phycotoxins, commonly referred to as lipophilic toxins, is liquid chromatography tandem mass spectrometry (LCMS/MS method), where coeluting components from the matrix can affect the efficiency of ionisation, resulting in erroneous quantification. In this study, the matrix effect was evaluated using the slope ratio analysis method, which involves comparing the slopes of the calibration curves in the matrix with those in pure solvent. The extent of the matrix effect was investigated in mussels, oysters, queen scallops and ascidians. The study covered all phycotoxins under Regulation EU 853/2004 for which certified standards are commercially available, including unregulated pectenotoxin 2. The results indicated that all lipophilic toxins were susceptible to this effect when LC-MS/MS was used for their determination. Significant ion suppression was evident for most analytes in all matrices, except for okadaic acid and dinophysistoxin 2 in bivalves, where significant ion enhancement was demonstrated, and dinophysistoxin 1 in oyster and scallop extract where no significant effect on ionisation was observed. Further analysis revealed no significant differences between the slope of mussel matrix-matched calibration and that of other bivalve matrices. Given this minor difference, the mussel matrix-matched calibration curve could be applied to minimise the matrix effect and to quantify phycotoxins in bivalve matrices analysed here, with the exception of the okadaic acid group in ascidians, which requires matrix-matched calibration prepared with the blank extract of these mentioned species. Given the risks phycotoxins pose to human health, ongoing analytical method development is necessary in this field to properly control food safety and ensure consumer health.

Gas chromatography-stable isotope ratio mass spectrometry prior solid phase microextraction and gas chromatography-tandem mass spectrometry: development and optimization of analytical methods to analyse garlic (Allium sativum L.) volatile fraction

Garlic (Allium sativum L.) is not only appreciated for its flavour and taste, but it is also recognized for various health properties. The European Commission, through the attribution of the Protected Designation of Origin (PDO) certification mark, has officially recognized some specific varieties of garlic. To protect not only the commercial value but also the reputation of this appreciated product, effective tools are therefore required. For the first time, a new compound specific isotope analysis method based on carbon stable isotopic ratio measurement of the three major volatile garlic compounds allyl alcohol (AA), diallyl disulphide (DD) and diallyl trisulphide (DT) through head-space solid phase microextraction (HS-SPME) followed by gas chromatography-combustion-isotope ratio mass spectrometry (GC-C-IRMS) was developed. A within-day standard deviation (Srwithin-day) of 0.3 ‰, 0.4 ‰ and 0.2 ‰ for δ(13C) and a between-day standard deviation (Srbetween-day) of 0.8 ‰, 1.0 ‰ and 0.6 ‰ of AA, DT and DD was estimated. For the first time, the ranges of isotopic variability for the three volatile compounds of red garlic from two neighbouring Italian regions (Abruzzo and Lazio) were defined analysing 30 samples. The same dataset was also considered in analysing the percentage composition of the previously mentioned three volatile compounds through HS-SPME followed by gas chromatography-tandem mass spectrometry (GC-MS/MS). The two analytical approaches were combined in this explorative study, aiming to provide potential parameters to discriminate garlic samples based on their geographical origin.

Influence of oligonucleotides structures for separation of diastereomers by capillary electrophoresis method using polyvinylpyrrolidone 1,300,000

In the field of oligonucleotides drug discovery, phosphorothioate (PS) modification has been recognized as an effective tool to overcome the nuclease digestion, and generates 2n of possible diastereomers, where n equals the number of PS linkages. However, it is also well known that differences in drug efficacy and toxicity are caused by differences in stereochemistry of oligonucleotides. Therefore, the development of a high-resolution analytical method that enables stereo discrimination of oligonucleotides is desired. Under this circumstance, capillary electrophoresis (CE) using polyvinylpyrrolidone (PVP) is considered as one of the useful tools for the separation analysis of diastereomers.In this study, we evaluated the several oligonucleotides with the structural diversities in order to understand the separation mechanism of the diastereomers by CE. Especially, five kinds of 2′-moieties were deeply examined by CE with PVP 1,300,000 polymer solution. We found that different trend of the peak shapes and the peak resolution were observed among these oligonucleotides. For example, the better peak resolution was observed in 6 mer PS3-DNA compared to the rigid structure of 6 mer PS3-LNA. As for this reason, the computational simulation revealed that difference of accessible surface area caused by the steric structure of thiophosphate in each oligonucleotide is one of the key attributes to explain the separation of the diastereomers. In addition, we achieved the separation of sixteen peak tops of the diastereomers in 6 mer PS4-DNA, and the complete separation of fifteen diastereomers in 6 mer PS4-RNA. These knowledge for the separation of the diastereomers by CE will be expected to the quality control of the oligonucleotide drugs.