1,720,990 research outputs found
Portable electrochemical sensor for trace analysis of ciprofloxacin in water and pharmaceutical samples
No full textTrace-level monitoring of ciprofloxacin (CPRO) in aquatic environments is essential for managing antibiotic pollution and bacterial resistance. This study presents a cost-effective portable sensor that employs square-wave anodic stripping voltammetry (SWASV) at an unmodified glassy carbon electrode (GCE) operated in acetate buffer. Detailed optimization tests were performed with the aim of finding the best parameters for this purpose. In particular, deposition time and frequency were tested and all the analytical performance were verified. River-water recoveries attained concentrations obtained by HPLC-MS/MS, HPLC-DAD, and UV/Vis methods. On-site measurements agreed with laboratory analyses, validating field applicability. The protocol also quantified a commercial eye-drop formulation demonstrating applicability of system to pharmaceutical excipients. Overall, the SWASV-GCE method provides a robust, low-cost method for rapid in-situ determination of ciprofloxacin in environmental waters and pharmaceutical matrices. Additionally, a green profile evaluation by means of the recent tools was also addressed and discussed
Green extraction, chemical profile and biological activity of waste products from the olive oil industry: From waste to wealth
Full text linkOlive oil is the most used vegetable oil for human consumption and its production represents an important economic sector, especially in Mediterranean countries. Olive trees are grown in more than 40 countries around the world on over 10 million hectares. The milling industry generates large quantities of liquid and solid residues, the disposal of which requires sophisticated and rather expensive procedures, given the polluting characteristics of the processing products. Since a considerable measure of olive-derived biomass is generated each year, it could be used as a potential source of bioactive compounds. This work evaluates the possibility of recovering natural antioxidants from by-products of the olive oil mill, through the optimization of extraction processes with green approaches. In the present work, through HPLC-PDA analysis with a validated method, it was possible to characterize a chemical profile of the extracts obtained through an optimized (DoE) and green approach. The waste products of the olive oil companies represent the samples considered in this work, and are derived from the pomace and the washing water of 2-phases, 2.5-phases, and 3-phase extra virgin olive oil (EVO) production plants. The optimized extraction methodology, starting from the 2.5-phase olive pomace, proved to be satisfactory in terms of efficiency by evaluating the effect of parameters such as extraction time and process temperature. The application of this methodology to other types of pomace and agro-industrial by-products has highlighted excellent results in terms of extraction yield, demonstrating the validity of this procedure as also suitable for other solid residues coming from the olive oil mill. Regarding the treatment in vegetation water, the developed protocol allowed the chromatographic profile of the analytes extracted from this matrix to be evaluated, leading to satisfactory results in terms of quantitative yields. Samples of these extracts are also subjected to biological tests in order to evaluate their antioxidant and enzyme inhibition activities
Evaluation of Antibody–Drug Conjugate Performances Using a Novel HPLC–DAD Method for Tumor-Specific Detection of DM4 and S-Methyl-DM4
No full textNew analytical challenges in characterization of Antibody-Drug Conjugates
Full text linkSince 1913, when Paul Ehrlich introduced the concept of “selective toxicity”, new strategies to obtain quality control, quantification of the drug were mandatory. For this reason, the introduction of antibody drug conjugates (ADC) has shown many critical points, being these systems made of small- and high-molecular weight compounds. Being ADCs a novelty for showing therapeutic action, they were subjected to a grow up in studies. There are in literature several approaches to follow ADCs for in vivo and in vitro studies because type of conjugation, release of the drug, and body-distribution are characteristic for each of them, resulting in many critical steps.
Liquid chromatography (LC) and capillary electrophoresis (CE) are the most common analytical technique used in order to obtain the aim. For the characterization of ADCs, there are several chromatographic techniques. HPLC finds application in both small and large molecules, related to the availability of various modes of separation (reversed-phase, size exclusion, ion exchange, mixed-mode etc.). Capillary electrophoresis (CE) finds its main application in large molecule therapeutics, where its electrophoretic separation mechanism offers a distinct, and often superior, separation of macromolecules compared to classic chromatographic techniques. Several modes of CE, including capillary electrophoresis sodium dodecyl sulphate (CE-SDS), capillary zone electrophoresis (CZE), and capillary isoelectric focusing (CIEF) or imaged capillary isoelectric focusing (iCIEF) are commonly utilized in characterization of the critical quality attributes (CQAs) of monoclonal antibody drugs such as charge variants, size variants, and positional isomers/purity etc.
In this review, analytical methods for physicochemical characterization of ADCs will be reported and analysed in order to highlight as the chromatographic procedures allow obtaining a complete ADCs evaluation and characterization
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Miniaturization in action: High-resolution, low-cost analytical platforms for biomedical and pharmaceutical research
No full textGrowing concerns over environmental pollution have led to increased emphasis on Green Chemistry and, more specifically, Green Analytical Chemistry (GAC). These frameworks advocate for the reduction of hazardous substances, minimization of waste, and consideration of the entire life cycle of analytical procedures—from production to disposal. Within this context, miniaturized analytical techniques have emerged as sustainable and efficient alternatives to conventional methods. Among these, capillary liquid chromatography (cLC), nano-liquid chromatography (nano-LC), and various modes of capillary electrophoresis (CE)—including micellar electrokinetic chromatography (MEKC), capillary isotachophoresis (CITP), capillary zone electrophoresis (CZE), capillary isoelectric focusing (CIEF), and capillary gel electrophoresis (CGE) have gained significant traction. Their advantages in terms of reduced solvent and sample consumption, enhanced resolution, and faster analysis times have made them particularly valuable in pharmaceutical and biomedical applications. One critical application area is the chiral separation of active pharmaceutical ingredients (APIs), which is increasingly vital in biotechnology, chemistry, agriculture, and especially the pharmaceutical industry. Electrokinetic chromatography (EKC) has proven to be an effective and versatile technique for this purpose, offering high resolution, flexibility, speed, and cost-efficiency. The growing availability of novel chiral selectors further enhances its appeal for the separation of enantiomeric drug compounds. This review provides an overview of recent advancements in miniaturized analytical techniques and highlights their applications in the biomedical and pharmaceutical sectors, with a particular focus on chiral separations using EKC
HPLC-DAD validated method for DM4 and its metabolite S-Me-DM4 quantification in biological matrix for clinical and pharmaceutical applications
Full text link: The present study focuses on the development and validation of an HPLC-DAD methodology for the detection of a potent chemotherapeutic agent, Maytansinoid Ravtansine (DM4), and its metabolite, S-methyl-DM4 (S-Me-DM4), in plasma samples. Methodologically, after a simple protein precipitation with acetonitrile and after drying 1 mL of supernatant, the sample (suspended with N,N-Dimethylacetamide, DMA) was directly analyzed by HPLC under isocratic elution using a mobile phase comprising milliQ water and methanol (25:75, v:v), both acidified with 0.1 % v:v formic acid. Employing a flow rate of 1.0 mL/min and a reversed-phase GraceSmart RP18 column thermostated at 40 °C, we achieved complete resolution and separation of DM4 and S-Me-DM4 within 13 min. The optimized injection volume of 20 μL and the wavelength set at 254 nm were utilized for quantitative analyses. Rigorous validation has not only ensured its reliability and reproducibility but has also addressed potential limitations associated with methodological inconsistency. The limit of detection and quantification of the method were 0.025 and 0.06 μg/mL for both the analytes, respectively. The calibration curve showed a good linearity in the range 0.06-20 μg/mL. For both analytes, the intraday precision and trueness were 2.3-8.2 % and -1.1 to 3.1 %, respectively, while the interday values were 0.7-10.1 % and -10.4 to 7.5 %, respectively. The developed methodology enables the concurrent determination and quantification of free DM4 and its metabolite, free S-Me-DM4, making it a valuable tool for assessing the pharmacokinetics and pharmacodynamics of DM4-based therapies. In addition, the procedure was successfully applied to analyse the presence of free DM4 or its metabolite, free S-Me-DM4, in human plasma samples spiked with the 1959-sss/DM4 antibody-drug conjugate (ADC). The utilization of the herein validated methodology allowed to confirm the presence of these analytes, thereby providing insights into their potential release from the ADC structure
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