Analysis Of Biological Fluids Research Articles

Nasal exudate for diagnosis of stroke: fundamental studies through iron fractionation, total iron, and targeted protein determinations

During the last years, there has been an increasing research interest in the analysis of biological fluids requiring non-invasive sampling for biomedical and clinical applications. In this work, we have focused on the nasal exudate with the aim of investigating the potential use of this fluid to know the role of iron in stroke and also for diagnosis. Potential differences in the nasal exudate, collected in swabs, from diagnosed hemorrhagic stroke, ischemic stroke, and control groups were investigated with regard to total iron by inductively coupled plasma-mass spectrometry, iron fractionation studies by size exclusion chromatography together with post-column isotope dilution analysis, and four proteins containing iron (ferritin, transferrin, lactoferrin, and ferroportin) with ELISA kits. All these analyses represent an analytical challenge, considering the rather limited amount of sample (10–40 mg) available, being the nasal exudate extracted from the swab with 300 µL 10 mM Tris/HCl, pH = 7.4. Studies to obtain reliable analytical information, such as the blank contribution of the sampling step, evaluation of the extraction efficiency of the nasal exudate from the swab, and normalization strategies for data treatment, have been carried out. Results showed that despite the limited number of investigated samples, fractionation studies as well as the concentrations of ferritin and ferroportin obtained with ELISA kits showed a differential behavior between the different cohorts.

К вопросу оценки качества сырья из каспийской атерины (Atherina boyeri caspia (Risso, 1810))

The purpose of this work was to establish the informative value of methods of structural analysis of biological fluids in determining the prospects of using atherina (Atherina boyeri caspia (Risso, 1810)) as a source of dietary protein in aquaculture. For the first time, solid-phase structures of atherina muscle homogenates were studied. It is known that the solid phase of biological fluids formed under conditions of wedge-shaped dehydration is a visualization of biochemical processes occurring in an organism or organ. The study of the morphological picture of a dried drop (facies) makes it possible to establish associative links between the features of the structuring of the studied liquid and its composition, as well as to determine the nature of the impact of environmental factors on a living system. The results of the study made it possible to establish the main type of homogenate facies and its morphological parameters, which indicate the consistency of biochemical processes and the presence of high-grade protein in the muscle tissue of the Caspian atherina, caught both in the spring and autumn seasons. The size and weight parameters of fish, the content of water-soluble protein in muscle tissue are characterized. For the first time, a comparative analysis of the level of water-soluble protein and solid-phase structures of muscle homogenates of Caspian atherina caught in different seasons in the coastal waters of Dagestan was carried out. Atherina is a food component for many fish living in the Caspian Sea. It was determined that in October, the content of muscle water-soluble protein in atherina tended to increase relative to March. During the feeding period, the accumulated part of the protein components turns into lipid components, which accumulate intensively, therefore, there are no significant seasonal differences in the content of water-soluble protein. It has been established that the biochemical processes occurring in muscle tissues are reflected in the solid-phase structures of biological fluids formed under conditions of wedge-shaped dehydration. The obtained results of the trend towards an increase in water-soluble muscle proteins in the body and an increase in the population in recent years indicate the importance of the use of Caspian atherina in the quality of live feed at fish farms.

Extralong hot-spots sensor for SERS sensitive detection of phthalate plasticizers in biological tear and serum fluids.

Phthalate plasticizers (PAEs) illegally used in food pose a great threat to human health. A new and efficient sensing platform for the sensitive detection of the PAE residues in biological fluids needs to be designed and developed. Here, we report a simple and reliable surface-enhanced Raman spectroscopy (SERS) active platform with extralong hot spots of Au nanobipyramids@Ag nanorods (Au NBPs@Ag NRs) for the rapid and sensitive detection of PAEs in biological fluids. To achieve high activity, Au NBPs@Ag NRs with different shell lengths were fabricated by controlling the synthesis conditions, and the corresponding SERS properties were investigated by using crystal violet (CryV) and butyl benzyl phthalate (BBP). The experimental results showed that a longer shell length correlated to greater Raman activity, which was confirmed by finite-difference time-domain (FDTD) electromagnetic simulation. More importantly, the extralong hot spots of the Au NBPs@Ag NR SERS-active substrate showed excellent homogeneity and reproducibility for the CryV probe molecules (6.21%), and the detection limit was 10-9M for both BBP and diethylhexyl phthalate (DEHP). Furthermore, through the standard addition method, an extralong hot spots SERS substrate could achieve highly sensitive detection of BBP and DEHP in serum and tears fluids, and the detection limit was as low as 3.52 10-8M and 2.82 10-8M. Therefore, the Au NBPs@Ag NR substrate with an extraordinarily long surface is efficient and versatile, and can potentially be used for high-efficiency sensing analysis in complex biological fluids.

Phytosterols in human serum as measured using a liquid chromatography tandem mass spectrometry

Phytosterols are lipophilic compounds found in plants with structural similarity to mammalian cholesterol. They cannot be endogenously produced by mammals and therefore always originate from diet. There has been increased interest in dietary phytosterols over the last few decades due to their association with a variety of beneficial health effects including low-density lipoprotein cholesterol lowering, anti-inflammatory and anti-cancerous effects. They are proposed as potential moderators for diseases associated with the central nervous system where cholesterol homeostasis is found to be imperative (multiple sclerosis, dementia, etc.) due to their ability to reach the brain. Here we utilised an enzyme-assisted derivatisation for sterol analysis (EADSA) in combination with a liquid chromatography tandem mass spectrometry (LC-MSn) to characterise phytosterol content in human serum. As little as 100 fg of plant sterol was injected on a reversed phase LC column. The method allows semi-quantitative measurements of phytosterols and their derivatives simultaneously with measurement of cholesterol metabolites. The identification of phytosterols in human serum was based on comparison of their LC retention times and MS2, MS3 spectra with a library of authentic standards. Free campesterol serum concentration was in the range from 0.30-4.10 µg/mL, β-sitosterol 0.16-3.37 µg/mL and fucosterol was at lowest concentration range from 0.05-0.38 µg/mL in ten individuals. This analytical methodology could be applied to the analysis of other biological fluids and tissues.

Development of D-π-A organic dyes for discriminating HSA from BSA and study on dye-HSA interaction

HSA (human serum albumin), a most abundant protein in blood serum, plays a key role in maintaining human health. Abnormal HSA level is correlated with many diseases, and thus has been used as an essential biomarker for therapeutic monitoring and biomedical diagnosis. Development of small-molecule fluorescent probes allowing the selective and sensitive recognition of HSA in in vitro and in vivo is of fundamental importance in basic biological research as well as medical diagnosis. Herein, we reported a series of new synthesized fluorescent dyes containing D-π-A constitution, which exhibited different optical properties in solution and solid state. Among them, dye M−H−SO3 with a hydrophilic sulfonate group at electron-acceptor part displayed selectivity for discrimination of HSA from BSA and other enzymes. Upon binding of dye M−H−SO3 with HSA, a significant fluorescence enhancement with a turn-on ratio about 96-fold was triggered. The detection limit was estimated to be ∼ 40 nM. Studies on the interaction mechanism revealed that dye M−H−SO3 could bind to site III of HSA with a 1:1 binding stoichiometry. Furthermore, dye M−H−SO3 has been applied to determine HSA in real urine samples with good recoveries, which provided a useful method for HSA analysis in biological fluids.

Characterization of the plasma proteome from healthy adult dogs.

Bloodwork is a widely used diagnostic tool in veterinary medicine, as diagnosis and therapeutic interventions often rely on blood biomarkers. However, biomarkers available in veterinary medicine often lack sensitivity or specificity. Mass spectrometry-based proteomics technology has been extensively used in the analysis of biological fluids. It offers excellent potential for a more comprehensive characterization of the plasma proteome in veterinary medicine. In this study, we aimed to identify and quantify plasma proteins in a cohort of healthy dogs and compare two techniques for depleting high-abundance plasma proteins to enable the detection of lower-abundance proteins via label-free quantification liquid chromatography-mass spectrometry. We utilized surplus lithium-heparin plasma from 30 healthy dogs, subdivided into five groups of pooled plasma from 6 randomly selected individuals each. Firstly, we used a commercial kit to deplete high-abundance plasma proteins. Secondly, we employed an in-house method to remove albumin using Blue-Sepharose. Among all the samples, some of the most abundant proteins identified were apolipoprotein A and B, albumin, alpha-2-macroglobulin, fibrinogen beta chain, fibronectin, complement C3, serotransferrin, and coagulation factor V. However, neither of the depletion techniques achieved significant depletion of highly abundant proteins. Despite this limitation, we could detect and quantify many clinically relevant proteins. Determining the healthy canine proteome is a crucial first step in establishing a reference proteome for canine plasma. After enrichment, this reference proteome can later be utilized to identify protein markers associated with different diseases, thereby contributing to the diagnosis and prognosis of various pathologies.

Nickel oxide electroplating and electrode surface modification for electrochemical detection of glutamate

The electrochemical behavior and catalytic properties of nickel oxide (NiOx) are enhanced through cathodic electroplating and subsequent electrochemical activation in an alkaline aqueous electrolyte. The electrochemical detection of ʟ-glutamate becomes feasible by introducing an amine group through immobilizing APTES ((3-aminopropyl)triethoxysilane) on the NiOx surface, resulting in a positive charge. The synergistic effect of electrochemically activated electroplated NiOx and the APTES-modified surface facilitates the effective electrochemical detection of trace ʟ-glutamate. The APTES-activated NiOx electrode exhibits a linear detection range of 0.2 nM to 2 mM for glutamate. This relatively wide concentration range is promising for the analysis of human biological fluids.

Quantification of Plasma Dopamine in Depressed Patients Using Silver-Enriched Silicon Nanowires as SERS-Active Substrates.

A decrease in the levels of dopamine (DA)─a key catecholamine biomarker for major depressive disorder─highlights the need for quantitative analysis of biological fluids to aid in the early diagnosis of diverse neuropsychiatric disorders. This study developed silicon nanowires enriched with silver nanoparticles to serve as a surface-enhanced Raman scattering (SERS) substrate to enable precise and sensitive quantification of blood plasma DA levels in humans. The silver-enriched silicon nanowires (SiNWs@Ag) yielded flower-like assemblies with densely populated SERS "hot spots," allowing sensitive DA detection. By correlating DA concentration with Raman intensity at 1156 cm-1, the plasma DA levels in treatment-naïve patients with major depression (n = 18) were 2 orders of magnitude lower than those in healthy controls (n = 18) (6.56 × 10-10 M vs 1.43 × 10-8 M). The plasma DA concentrations differed significantly between the two groups (two-tailed p = 5.77×10-7), highlighting a distinct demarcation between depression patients and healthy controls. Furthermore, the SiNWs@Ag substrate effectively differentiated between DA and norepinephrine (NE) in mixtures at nanomolar levels, demonstrating its selective detection capability. This study represents the first report on the quantitative detection of DA levels in human blood samples from individuals with major depression using an SERS technique, emphasizing its potential clinical utility in the evaluation and diagnosis of neuropsychiatric disorders.

Cancer screening through surface-enhanced Raman spectroscopy fingerprinting analysis of urinary metabolites using surface-carbonized silver nanowires on a filter membrane

BackgroundLabel-free surface-enhanced Raman spectroscopy (SERS)-based metabolic profiling has great potential for early cancer diagnosis, but further advancements in analytical methods and clinical evidence studies are required for clinical applications. To improve the cancer diagnostic accuracy of label-free SERS spectral analysis of complex biological fluids, it is necessary to obtain specifically enhanced SERS signals of cancer-related metabolites present at low concentrations. ResultsThis study presents a novel 3D SERS sensor, comprising a surface-carbonized silver nanowire (AgNW)-stacked filter membrane, alongside an optimized urine/methanol/chloroform extraction technique, which specifically changes the molecular adsorption and orientation of aromatic metabolites onto SERS substrates. By analyzing the pretreated urine samples on the surface-carbonized AgNW 3D SERS sensor, distinct and highly enhanced SERS peaks derived from semi-polar aromatic metabolites were observed for pancreatic cancer and prostate cancer samples compared with normal controls. Urine metabolite analysis using SERS fingerprinting successfully differentiated pancreatic cancer and prostate cancer groups from normal control group: normal control (n = 56), pancreatic cancer (n = 40), and prostate cancer (n = 39). Significance and noveltyWe confirmed the clinical feasibility of performing fingerprint analysis of urinary metabolites based on the surface-carbonized AgNW 3D SERS sensor and methanol/chloroform extraction for noninvasive cancer screening. This technology holds potential for large-scale screening owing to its high accuracy, and cost effective, simple and rapid detection method.

Synthesis of 15N-Pyridines and Higher Mass Isotopologs via Zincke Imine Intermediates.

Methods to incorporate stable radioisotopes are integral to pharmaceutical and agrochemical development. However, despite the prevalence of pyridines in candidate compounds, methods to incorporate 15N atoms within their structures are limited. Here, we present a general approach to pyridine 15N-labeling that proceeds via ring-opening to NTf-Zincke imines and then ring-closure with commercially available 15NH4Cl salts. This process functions on a range of substituted pyridines, from simple building block-type compounds to late-stage labeling of complex pharmaceuticals, and 15N-incorporation is >95% in most cases. The reactivity of the Zincke imine intermediates also enables deuteration of the pyridine C3- and C5-positions, resulting in higher mass isotopologs required for LCMS analysis of biological fluids during drug development.

Формирование текстурных признаков хронического воспаления околоносовых пазух (экспериментальное исследование)

Relevance. Morphological examination of the solid phase of biological fluids for the purpose of diagnosing a pathological process is currently quite widely used in various fields of medicine. The current stage of development of the morphological study of human biological fluids is the use of new technology for computer statistical analysis of biological fluids at the stage of solid sediment. The technology is based on identifying structural markers of a pathological process in images of the solid phase of biological fluids. In previous studies based on the Mathematica 13 program (Wolfram Research), we discovered markers of disturbances in the structure of the solid phase of nasal secretions in chronic rhinosinusitis. A system of computer algorithms was created that revealed the main textural features of these structural markers in the pathology under study (entropy, fractal dimension, degree of homogeneity). In a previous study, we presented the statistical processing based on the use of a system of computer algorithms served as the basis for automated analysis of the solid phase of biological fluids for diagnosing the pathological process. However, to date, the process of formation of structures characteristic of normal and pathological conditions during dehydration of biological fluid has not been sufficiently studied. In this regard, conducting an experimental study of the process of formation of textural signs of chronic rhinosinusitis for the scientific substantiation of their diagnostic use in practical otorhinolaryngology is currently of undoubted relevance. Objective. To assess the dynamics of the formation of textural signs of chronic rhinosinusitis during dehydration of nasal secretions. Materials and methods. An experimental study was conducted on the dynamics of the formation of textural signs of chronic rhinosinusitis in the process of dehydration of the secretion of the nasal mucosa in 60 patients with this disease through a comparative morphological assessment of raster images of textures. Experimental, biophysical, statistical methods, conversion of liquids into the solid phase (wedge-shaped dehydration), video microscopy, and computer mathematical analysis of images were used. Results. The experimental studies made it possible to quantify the dynamics of the formation of textural features of the inflammatory process in the paranasal sinuses (entropy, fractal dimension, degree of homogeneity) during the systemic self-organization of nasal secretions using the wedge-shaped dehydration method in patients with chronic rhinosinusitis. Conclusion. The presented data indicate that the textural features obtained during statistical processing (entropy, fractal dimension, degree of homogeneity) represent objective characteristics of structural markers of the solid phase formed during dehydration of nasal secretions in chronic rhinosinusitis, which justifies the use of statistical analysis of textures of the solid phase of biological fluids in automated mode for diagnosing chronic rhinosinusitis in clinical otorhinolaryngological practice.

A greener RP-HPTLC-densitometry method for the quantification of apremilast in nanoformulations and commercial tablets: Greenness assessment by analytical eco-scale, ChlorTox, and AGREE methods

The greener “high-performance thin-layer chromatography (HPTLC)” methods for apremilast (APM) analysis in pharmaceutical products and biological fluids are not currently available in the literature. Accordingly, this study involves the development and validation of a rapid, simple, economical, and greener reversed-phase HPTLC methodology for the estimation of APM in prepared nanoparticles (NPs), nanoemulsion, and marketed tablets. The estimation of APM was conducted using “RP-18 silica gel 60 F254S HPTLC plates” as the stationary phase. The combination of ethanol/water (65:35, v/v) was used as the greener mobile phase for APM analysis. The greenness of the method was predicted using three different approaches, namely Analytical Eco-Score (AES), ChlorTox, and the Analytical GREENness (AGREE) approaches. The λmax = 238 nm was used for the APM detection. By contrasting its single band at Rf = 0.61 ± 0.01 with those of pure APM, the HPTLC peaks for APM in an prepared NP formulation, nanoemulsion, and marketed tablets were identified. In the concentration range of 100–700 ng/band, the proposed analytical methodology was linear. The values of AES, ChlorTox, and AGREE were determined to be 93, 0.66 g, and 0.89, respectively, demonstrated an outstanding greener profile for the existing method. The amount of APM in the tablet, NP formulation, and nanoemulsion was found to be 98.40, 101.60, and 99.37 %, respectively. According to the findings of validation tests and pharmaceutical analysis, the suggested analytical technique could be successfully applied for the routine examination of APM in marketed tablets and laboratory generated nanoformulations.

VALIDATION OF HEADSPACE SOLID-PHASE MICROEXTRACTION WITH GAS CHROMATOGRAPHY-FLAME IONISATION DETECTOR METHOD FOR ALCOHOL ANALYSIS ON GASTRIC FLUID

Identifying the concentration of alcohol compounds in postmortem analysis of biological fluids can help the investigation, just as postmortem analysis of gastric juices can reveal the concentrations of alcohol consumed. However, an efficient and effective combination of extraction and measurement methods is required when looking at complex postmortem samples. Therefore, a headspace-solid phase microextraction (HS-SPME) method was developed using gas chromatography with a flame ionization detector (GC-FID) to identify postmortem alcohol concentrations. This present study optimizes and validates an effective and efficient method for postmortem alcohol extraction and quantification in gastric fluid. The optimal conditions for HS-SPME extraction using 65μm Polydimethy lsiloxane Divinyl benzene (PDMS/DVB) fiber for analyte isolation were 15 minutes. at 60°C and an exposure time of 1 minute. The validation investigation shows that the suggested approach satisfies the criteria for linearity, precision, accuracy, LOD, and LOQ for postmortem measurement of alcohol in gastric fluid.

Strategies in sample preparation for proteome analysis of biological fluids from water buffaloes

Livestock species such as water buffalo have some unique characteristics like high fat percentage in milk and plasma, poor sample generation, peculiar behaviour, etc. making it difficult for proteomic analysis of such samples. Additionally, there is a limited database in terms of identified proteins, characterised antibodies and functional attributes of known molecules specific to buffalo. The body fluids like blood, milk, urine and foetal fluids offer a great opportunity in understanding physio-pathological processes and thus aid in developing reliable diagnostics. Standardised sample preparation protocols are key to advancement of proteomics science. Optimising sample preparation for 2-DE proteomics in buffalo serum, milk, and foetal fluids is crucial. Commercially available kits or laboratory methods for clean-up, enrichment, and condition optimising can be applied for getting optimum results. The 2-D clean up strategy is an important step in sample preparation procedures to get rid of inferring substances which hamper IEF. The sample preparation of the buffalo biological fluids (serum, foetal fluids, maternal uterine flushing and milk samples) reported in the present study shall provide valuable information for further research.

ICP-MS and fluorescence dual-mode detection of ZIKV-RNA based on quantum dot labeling with hybridization chain reaction

The detection of Zika virus (ZIKV) is of great significance to human life and health. Herein, we presented an ICP-MS and fluorescent dual-mode sensor for quantitative analysis of Zika virus RNA fragments (ZIKV-RNA), which employed quantum dots (QDs) as signal tags and combined with hybridization chain reaction (HCR). The dual-mode sensor realized cross-checking of the analysis results and improved the assay accuracy. Firstly, the single-stranded DNA (ssDNA) was anchored on the surface of magnetic beads (MBs). Afterward, HCR was conducted with probe DNA-CdSe quantum dots conjugates (pDNA-QDs) and link DNA (lDNA), producing the MBs-ssDNA-[pDNA-QDs-lDNA]n conjugates. In the presence of target ZIKV-RNA, a strand displacement reaction occurred, leading to the dissociation of the [pDNA-QDs-lDNA]n labels from the conjugates into the solution. Finally, the signal intensity was detected using ICP-MS and fluorescence analysis, with achieved limits of detection of 131 pM and 152 pM, respectively. The inter-assay RSD values of fluorescence and ICP-MS were 3.94 % and 4.26 % at 10 nM level, respectively, showing that the method had good precision. This method showed high selectivity and was applied to the analysis of biological fluids. There was no significant difference between the results of ICP-MS modes and fluorescence mode. This method offers a new strategy for sensitivity analysis of ZIKV-RNA and exhibits promise in clinical applications for diagnosis.

Interpretation of results of automated analysis of pleural effusion (clinical cases)

Automated analysis of effusion fluids, providing a large amount of objective information about a biological sample, has significantly expanded the diagnostic capabilities of the cytological service. At the same time, there are currently no unified algorithms for interpreting the obtained data. The aim of the work was to develop, based on the results of automated analysis of pleural fluids, alternative predictions of the genesis of the effusion (benign / malignant). The study was carried out on the basis of the Clinical Regional Hospital No. 2 in Krasnodar (Russia). The results of automated analysis of biological fluids obtained using the Sysmex XN analyzer were compared with the data of cytological, laboratory and instrumental studies. The article presents some of our own developments that can serve as indicative criteria for interpreting the results of automated analysis of biological fluids. It has been established that in terms of differential diagnosis of the genesis of effusion, the indicators of total cytosis (TC-BF) and the absolute content of highly fluorescent mononuclear cells (HF-BF#) are the most informative. Accounting for clinical data, results of laboratory and instrumental studies increases the informative value of automated analysis of biological fluids.

Alterations in glutamate, arginine, and energy metabolism characterize cerebrospinal fluid and plasma metabolome of persons with HIV-associated dementia.

HIV-associated dementia (HAD) is the most severe clinical expression of HIV-mediated neuropathology, and the processes underlying its development remain poorly understood. We aimed to exploit high-dimensional metabolic profiling to gain insights into the pathological mechanisms associated to HAD. In this cross-sectional study, we utilized metabolomics to profile matched cerebrospinal fluid (CSF) and plasma samples of HAD individuals ( n = 20) compared with neurologically asymptomatic people with HIV (ASYM, n = 20) and healthy controls (NEG, n = 20). Identification of plasma and CSF metabolites was performed by liquid-chromatography or gas-chromatography following a validated experimental pipeline. The resulting metabolic profiles were analyzed by machine-learning algorithms, and altered pathways were identified by comparison with KEGG pathway database. In CSF, HAD patients displayed an imbalance in glutamine/glutamate ratio, decreased levels of isocitrate and arginine, and increased oxidative stress when compared with ASYM or NEG. These changes were confirmed in matched plasma samples, which in addition revealed an accumulation of eicosanoids and unsaturated fatty acids in HAD individuals. Pathway analysis in both biological fluids suggested that alterations in several metabolic processes, including protein biosynthesis, glutamate and arginine metabolism, and energy metabolism, in association to a perturbed eicosanoid metabolism in plasma, may represent the metabolic signature associated to HAD. These findings show that HAD may be associated with metabolic modifications in CSF and plasma. These preliminary data may be useful to identify novel metabolic biomarkers and therapeutic targets in HIV-associated neurological impairment.

A green sustainable ultrasensitive micelle-sensitized spectrofluorimetric approach for the estimation of tafamidis in different matrices at picogram levels

Tafamidis is a novel drug approved by the European Medicines Agency to treat certain forms of transthyretin amyloidosis. The current study introduces a new ultrasensitive validated spectrofluorimetric approach for tafamidis analysis in bulk, capsules, and biological fluids. The present study is considered the first spectrofluorimetry-based approach for tafamidis estimation. The proposed eco-friendly spectrofluorimetric method depended on the measurement of the enhanced native fluorescence of tafamidis exhibited at 310/370 nm without any derivatization reaction. It was found that about two-fold enhancement in the tafamidis fluorescence could be accomplished by the addition of Brij-35. Different experimental parameters affecting the fluorescence of tafamidis were examined to reach the optimal conditions and highest sensitivity. One milliliter of each of 0.02 M Britton-Robinson buffer at pH 2 and Brij-35 was added to give the maximum fluorescence intensity. The drug was successively assayed in the concentration range of (0.1–10.0 ng/mL) with a detection limit of 0.0107 ng/mL and a quantitation limit of 0.0324 ng/mL. Owing to the superior sensitivity and selectivity, the developed method was effectively applied to the quantitation of tafamidis in its capsules and spiked human plasma samples with high % recoveries and low % relative standard deviation values. The validation parameters were assessed by following the International Council for Harmonization (ICH) guidelines. Additionally, the eco-friendly property of the designed approach was considered, and the greenness was evaluated using the Green Analytical Procedure Index (GAPI) and Analytical GREENNESS metric approach (AGREE).

Spectroscopic and Chromatographic Estimation of Some Sartans and their Combinations with Thiazide Diuretics: A Review

Abstract: Sartans are often used as antihypertensives. They are also available in combination with thiazide diuretics for the management of hypertension. Analytical method development is a crucial part of successful drug development and characterization. Bioanalytical studies are of paramount importance while establishing pharmacokinetic and toxicokinetic data while forced degradation studies are important to elucidate degradation pathways and to establish stability of the drugs. : Different methods have been developed for the analysis of sartans and their combination with thiazide diuretics. We thought it imperative to summarize them so the data could be useful for analysis of newer sartans. The review describes various methods for analysis of some frequently employed sartans as well as the latest sartans and their combination with thiazide diuretics. The article also focuses on their analysis of biological fluids. Forced degradation studies have also been covered in the article. : Article is divided into three sections. First section covers introduction, second section focuses on different methods developed, including bioanalytical methods, while third section presents forced degradation studies carried out on the drugs. Important parameters of the analytical methods developed have been summarized in tabular form.

Voltammetric analysis of biological fluids: quantification of species in urine accounting for non-linear concentration effects

Voltammetric sensing of analytes in biological fluids is frequently accompanied by non-linear effects due to the analyte/matrix interactions. A theoretical approach is developed to describe such effects when standard addition methods are applied. Several asymptotic models are described considering equilibrium-like and kinetic-like interaction models and possible co-diffusion effects. Experimental data for non-linear features which appear in voltammetric sensing of serotonin and noradrenalin in urine are in satisfactory agreement with theoretical predictions.