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Quantitative analysis of mixed lipid nanostructures in rat skin by HPLC-MS

Abstract Liquid chromatography-mass spectrometry (LC-MS) is a very sensitive technique for determining small concentrations of drugs in fixed dose combinations or even those deposited in skin layers. Therefore, an LC-MS method was applied for determining the drugs under investigation, namely, clioquinol (CLIO), tolnaftate (TOL), and betamethasone (BETA) in Quadriderm® cream and mixed lipid nanostructures (MLNs) prepared in laboratory in the presence of potential interferents, and was applied as a dermato-kinetic study in rat’s skin. The separation was achieved within 4.5 min by using C18 column as a stationary phase and the mobile phase used were 20% phase A composed of 0.1% formic acid (v/v) and 80% phase B composed of 0.1% formic acid in acetonitrile (v/v), coupled with triple quadrupole mass spectrometer. MLNs were prepared and characterized to be compared with the conventional commercially available Quadriderm® cream. The proposed method was accurate and precise with a linearity range of 0.2–20.0 µg·mL−1 for BETA, and 0.5–400.0 µg·mL−1 for CLIO and TOL and a better bioavailability of the new formulation was obtained ensuring the capability of the nanoparticles to accumulate the drugs within the skin layers. In conclusion, the LC-MS method was accurate and precise for the determination of the three drugs under investigation in cream dosage form and skin tissues.

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Sustainable HPLC technique for measurement of antidiabetic drugs: Appraisal of green and white metrics, content uniformity, and <i>in vitro</i> dissolution

Abstract Green chemistry and white chemistry are two approaches to chemistry that prioritize sustainability and environmental protection. The pursuit of green chemistry is to develop chemical processes and products that decrease or stop the use and generation of dangerous materials. In contrast, white chemistry focuses on developing energy-efficient, sustainable chemical processes that produce minimal waste. Our study evaluated the environmental friendliness of the suggested approach, using eight greenness appraisal techniques, including analytical eco-scale, analytical method volume intensity, HPLC-environmental assessment tool, analytical method greenness score, analytical greenness, analytical greenness metric for sample preparation, green analytical procedure index, and complexgreen analytical procedure index, in addition to the unique metric blue applicability grade index of white chemistry. We have developed and validated a highly effective and reliable method for concurrently analyzing designated pharmaceutical medications characterized in metformin (MET) and empagliflozin (EMP) formulations, including their degraded products. This method is cost-effective, specific, and environmentally friendly, utilizing reversed-phase high-performance liquid chromatography with an XBridge BEH C8 column (150 mm × 4.6 mm, 5 μm) at a flow rate of 1.0 mL·min−1, an injection volume of 5.0 μL, a column oven temperature of 50°C, a wavelength of 224 nm, and a mobile phase comprised of phosphate buffer adjusted at pH 6.8 and acetonitrile in gradient mode. In the HPLC method, linearity has been achieved over the concentration range of 10–106 and 30–1,050 µg·mL−1 for EMP and MET, respectively, with correlation coefficients more than 0.999 and good recoveries within 98–102%. An assessment of the content uniformity of finished products confirmed that they met the declaration’s acceptance standards (85–115%). A comparative study has been successfully conducted on generic and reference products, demonstrating their similarity. The suggested approach was validated by adhering to international council for harmonisation criteria.

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A novel Six Sigma approach and eco-friendly RP-HPLC technique for determination of pimavanserin and its degraded products: Application of Box–Behnken design

Abstract A green analytical chemistry study attempts to generate environmentally friendly alternatives to dangerous compounds while reducing waste output. The study thoroughly analyzed eight green tools to determine their greenness. Given its importance in treating hallucinations and delusions produced by Parkinson’s disease psychosis, it is critical to have a reliable and precise method for identifying pimavanserin (PVS) in both pure form and pharmaceutical formulations. The current study used a straightforward approach to forced degradation experiments to establish a novel reversed-phase high-performance liquid chromatography method for evaluating stability. The method was executed on the Agilent Zorbax Eclipse Plus C18 column (100 × 4.6 mm, 3.5 μm particle size) with ultraviolet detection at 226 nm. The Box–Behnken design is the ultimate solution for identifying optimal chromatographic conditions in a timely and efficient manner, with minimal trials required. The study investigated the impact of three factors: acetonitrile ratio, column oven temperature, and flow rate on various responses, namely, retention time, tailing factor, and theoretical plates. Desirability and overlay plots were utilized to forecast the best mobile phase containing a buffer solution: acetonitrile: tetrahydrofuran in a ratio of (65: 20: 15, v/v/v), which proved highly effective in the experiments. Linearity was conducted for PVS in the 3–50 µg·mL−1 range with an R 2 coefficient of determination of 0.9997. PVS had detection and quantification limits of 1.1 and 3.5 µg·mL−1, respectively, indicating a highly significant correlation between the variables studied. PVS’s recovery percentage was determined to be 101.30%. We also used the Six Sigma lean technique to ensure precision and productivity. PVS was tested for acid, base, oxidative hydrolysis, photodegradation, and heat, as per International Council for Harmonisation guidelines. The highest degradation was obtained from oxidative hydrolysis and thermal degradation.

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Recent advance in electrochemical immunosensors for lung cancer biomarkers sensing

Abstract Lung cancer has a high mortality rate largely due to late-stage diagnosis. Detecting protein and genetic biomarkers through electrochemical immunosensors enables non-invasive early diagnosis. This review discusses recent advances in electrochemical immunosensors for detecting clinically relevant lung cancer biomarkers. The use of nanomaterials like graphene, carbon nanotubes, metal nanoparticles, and conducting polymers in sensor fabrication improves electron transfer kinetics, enhances signal transduction, and allows higher antibody loading. Smart surface immobilization strategies optimize antibody orientation and binding capacity. Amplification approaches utilizing nanomaterials, enzymes, polymers, dendrimers, and DNA nanostructures are applied to enhance output signal per binding event. Various electroanalytical techniques including amperometry, potentiometry, impedance spectroscopy, and voltammetry are employed for quantitative monitoring. Recent immunosensors showcase low detection limits and wide linear ranges for measurement of major biomarkers like carcinoembryonic antigen, neuron specific enolase, and cytokeratin fragment 21-1. Emerging biomarkers such as microRNAs and circulating tumor cells have also been targeted. However, reproducibility, selectivity, multiplexing, and integration with point-of-care platforms need improvement for widespread clinical translation. Overall, electrochemical immunosensors hold immense potential for sensitive, affordable lung cancer diagnosis if ongoing efforts can address current limitations.

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Greenness of dispersive microextraction using molecularly imprinted polymers

Abstract Molecularly imprinted polymers (MIPs) as materials with determined levels of selectivity and specificity for designated analytes have recently gained much attention in various application fields. However, with the growing adoption of green analytical chemistry (GAC) principles, it is essential to investigate the greenness of MIP synthesis and its subsequent application in sample preparation, as well as to evaluate the “green” nature of the developed analytical methodologies, such as dispersive solid-phase microextraction (DSPME). Accordingly, the main objective of this research was to evaluate the greenness of MIP-based glycidyl methacrylate synthesis and MIP use as a DSPME sorbent prior to high-performance liquid chromatography with mass spectrometry (HPLC-MS). The green perspective of MIP-DSPME prior to HPLC-MS was investigated using various analytical metric tools such as the Analytical Eco-Scale, the Green Analytical Procedure Index, and Analytical GREEnness (AGREE). Since these analytical tools are not fully implementable for the assessment of the greenness of the MIP synthesis, some alternative approaches were used to optimize the synthesis parameters to make the MIP DSPME sorbent as close as possible to the GAC principles. The calculated AGREE score (0.62) and 91 points in the Analytical Eco-Scale for the proposed DSPME technique using MIP indicated a high level of greenness.

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Synthesis of a benzothiazole-based structure as a selective colorimetric-fluorogenic cyanate chemosensor

Abstract In this study, a new heterocyclic compound incorporating a benzothiazole moiety was specifically designed for the detection of cyanate anions, employing a hydrogen bonding mechanism. Through strategic integration of triazine and phenylenediamine cyclic groups into the compound’s structure, intramolecular hydrogen bonding interactions between the donor and acceptor sites were enhanced, leading to exceptional sensitivity towards cyanate anions. Utilizing the amino-type excited-state intramolecular proton transfer phenomenon, this new compound exhibited dual signals and achieved a significant Stokes’ shift via proton transfer, coupled with aggregation-induced emission properties. This unique combination resulted in visible color changes and an impressive fluorescence response, offering a promising solution for the sensitive detection of cyanate ions in critical environmental matrices. Cyanate detection at low concentrations by this as-synthesized compound (L1), accompanied by a distinct color change and a gradual fluorescence increase upon incremental cyanate addition demonstrated L1’s selectivity, as confirmed in the presence of various competing anions F−, Cl−, Br−, I−, ClO 3 − {\text{ClO}}_{3}^{-} , ClO 4 − {\text{ClO}}_{4}^{-} , NO 3 − {\text{NO}}_{3}^{-} , BrO 3 − {\text{BrO}}_{3}^{-} , CN− and CNO−. Spectrofluorometric investigations demonstrated that L1 shows significant potential as a selective cyanate anion detection candidate.

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