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Authors: Krähling János, Istvánfi Gyula, Alföldi György, Krizsán András, Kovács Csaba and Becker Gábor
Open access

Abstract

A simple and sensitive liquid chromatography-mass spectrometric (LC-MS) method has been developed and validated for the simultaneous determination of ezetimibe (EZE), atorvastatin calcium (ATO), and simvastatin (SMV) in combined dosage forms and human plasma. Successful separation of the studied drugs was achieved on a Zorbax Eclipse Plus C18 column (3.0 × 150 mm, 5 µm) using a mobile phase consisting of acetonitrile and 0.1% formic acid in water (65:35, v/v) at a flow rate of 0.5 mL min−1. Total run time was 9.3 min and diclofenac sodium was used as internal standard (IS). Positive selected ion monitoring (SIM) mode was applied where, the monitored ions were those at m/z values of 392.1, 559.3, 296.0, and 441.4 corresponding to EZE, ATO, IS, and SMV, respectively. The method was fully validated according to the ICH guidelines. The intraday and interday precision showed relative SD values not more than 1.77 and 1.99%; respectively. The limits of detection (LOD) were 0.25, 0.25, and 0.75 ng mL−1 while the limits of quantification (LOQ) were 1.25, 0.75, and 2.5 ng mL−1 for EZE, ATO, and SMV, respectively. The developed method was applied on two types of combined tablets concerning drug assay with mean percent recoveries within acceptable range. The method has been extended to the determination of the studied drugs in human plasma where, a solid phase extraction method was optimized for their extraction with percent recovery not less than 97%.

Open access

A Szerző Vámossy Ferenc munkatársaként 2000 óta segítette az Építés – Építészettudomány folyóirat megjelenését. E rövid visszatekintésben a közös munka állomásai, az idősödő professzor módszerei és hatása szerepelnek, hogyan segítette részletes tanácsaival, módszertani javaslataival a fiatalabb szerzőket, hogyan gondoskodott a lap tudományos színvonaláról. A folyóirat érdekében 60 éven át végzett, kimagasló munkáját 2017-ben zárta le egy magyar és angol nyelven megjelent, összefoglaló, visszaemlékező tanulmánnyal.

Open access

A Budapesti Műszaki és Gazdaságtudományi Egyetem Építészettörténeti és Műemléki Tanszékén a műemléki és történeti épületek felmérése évszázados múltra tekint vissza. Az oktatásban is rendkívül fontos szerepet betöltő felmérőtáborok hagyományát oktatóink, dr. Istvánfi Gyula és dr. Kalmár Miklós hosszú évtizedeken keresztül éltették tovább megszerettetve hallgatóikkal – így velünk is – a régi házak, szerkezetek megfigyelését, rajzolását és kutatását. Tanulmányunkban a Tanszék által 2017-ben a Pest megyei Ipolytölgyesen szervezett nyári felmérőtábor emlékét és tanulságait történeti és néprajzi kitekintéssel szeretnénk összefűzni. A tábor során felmért tíz portát főleg építészeti szempontból vizsgáltuk és dokumentáltuk, de ahogyan az minden épület tanulmányozása esetén fennáll, betekintést nyerhettünk a falu mindennapi életébe és értékeibe is.

Open access

Abstract

A sweeping micellar electrokinetic chromatography (sweeping-MEKC) enrichment model was established for the determination of three chlorophenols (CPs) in cosmetics, namely, bithionol, pentachlorophenol (PCP), and 2,4,6-trichlorophenol (2,4,6-TCP). The optimum electrophoretic conditions were 20 mM NaH2PO4-80 mM sodium dodecyl sulfate (SDS) and 30% (v/v) acetonitrile (pH 2.3). The optimum on-line concentration conditions were as follows: sample matrix, 100 mM NaH2PO4; pressure injection at 20.67 kPa (3 psi) for 25 s. The linear range of bithionol, PCP, and 2,4,6-TCP are 0.20–4.00 μg mL−1, 0.10–2.00 μg mL−1, and 0.05–2.00 μg mL−1 respectively, with correlation coefficient (r) over 0.9972. The limits of detection (LOD) based on three times the signal-to-noise ratio (S/N = 3) are in the range of 0.0061–0.024 μg mL−1. Recoveries for the three CPs in powder and lotion samples are between 79.7 and 110.2% with relative standard deviation (RSD) of 1.38–5.54% and 92.2–121.3% with RSD of 0.72–6.09%, respectively. The proposed method can provide reference for the determination of trace CPs in different sample matrix.

Open access

Abstract

This study focused on developing an effective and environmentally friendly method to measure ligustrazine in rat serum by using polymer monolith micro-extraction (PMME) technique. A poly (methacrylic acid-ethylene glycol dimethacrylate) material was used to extract ligustrazine through hydrophobic and ion-exchange interaction. Qualitative and quantitative analysis was performed by a liquid chromatography and tandem mass spectrometry. After optimization of several PMME conditions, the developed method exhibited excellent extraction performance to the ligustrazine. Good linearity was acquired ranging from 10 to 2,000 ng mL−1, and the limit of detection of the proposed method was 0.14 ng mL−1. The recoveries measured by spiking three different concentrations in rat serum ranged from 82.6 to 95.3%, and excellent precision was found with relative standard deviations (RSDs) less than 8.3% for intra-day and 9.7% for inter-day, respectively. At last, the applicability of the method was further confirmed through continuous monitoring of ligustrazine in rat serum after dosing of ligustrazine tablets to rats.

Open access

Abstract

Infections with multi-drug resistant (MDR) bacteria including carbapenem-resistant Klebsiella pneumoniae are emerging worldwide but are difficult to treat with the currently available antibiotic compounds and therefore constitute serious threats to human health. This prompted us to perform a literature survey applying the MEDLINE database and Cochrane Register of Controlled Trials including clinical trials comparing different treatment regimens for infections caused by carbapenem-resistant K. pneumoniae. Our survey revealed that a combined application of antibiotic compounds such as meropenem plus vaborbactam, meropenem plus colistin and carbapenem plus carbapenem, resulted in significantly increased clinical cure and decreased mortality rates as compared to respective control treatment. However, further research on novel antibiotic compounds, but also on antibiotic-independent molecules providing synergistic or at least resistance-modifying properties needs to be undertaken in vitro as well as in large clinical trials to provide future options in the combat of emerging life-threatening infections caused by MDR bacteria.

Open access

Akadémiai Értesítő

A Magyar Tudományos Akadémia Hivatalos Lapja

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