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EN
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%.
EN
A novel, simple, robust, and rapid reversed-phased high-performance liquid chromatographic method has been developed for the separation and quantitative determination of the related substances of ezetimibe and simvastatin in combined dosage forms. Successful separation of the drug from the process-related impurities and degradation products formed under stress conditions was achieved on Inertsil ODS-3V (150 × 4.6 mm, 5.0 μm) column. The gradient liquid chromatography (LC) method employs solution A and solution B as mobile phase. The solution A contains 0.1% orthophosphoric acid solution in water, and solution B contains 0.1% orthophosphoric acid solution in acetonitrile. Flow rate was monitored at 2.0 mL/min, and the ultraviolet (UV) detection, at 238 nm. In forced degradation studies, the effect of acid, base, oxidation, UV light, and temperature was investigated, showing that good resolution between the peaks corresponds to process-related impurities and degradation products from both analyte. The performance of the method was validated according to the present International Conference on Harmonization (ICH) guidelines for specificity, limit of detection, limit of quantification, linearity, accuracy, precision, ruggedness, and robustness. To the best of our knowledge, a rapid LC method, which separates all the impurities of ezetimibe and simvastatin in combined dosage forms, disclosed in this investigation was not published elsewhere.
PL
Zbadany został wpływ simwastatyny na degradację terpolimerów LL-laktydu, glikolidu i węglanu trimetylenu z pamięcią kształtu. Badano mechanizm degradacji in vitro, w izotonicznym roztworze chlorku sodu buforowanym fosforanami (PBS), matryc polimerowych wykonanych z dwóch materiałów z różną zawartością leku i bez simwastatyny. Polimery charakteryzowano przy użyciu: różnicowej kalorymetrii skaningowej (DSC) (właściwości termiczne), chromatografii żelowej (GPC) (masy cząsteczkowe) i spektroskopii magnetycznego rezonansu jądrowego (NMR) (skład i mikrostruktura). Profil uwalniania leku oceniano metodą spektroskopii UV-Vis. Oceniono przydatność badanych materiałów do zastosowania w produkcji biozgodnych polimerowych resorbowalnych chirurgicznych systemów z pamięcią kształtu z własnością kontrolowanego uwalniania leku. Nie odnotowano istotnego wpływu 1% zawartości leku na przebieg degradacji.
EN
The influence of simvastatin on degradation of terpolymers synthesized from L-lactide, glycolide, and trimethylene carbonate has been analyzed. The in vitro degradation of the matrices, obtained from two terpolymers with various chain structure and amount of simvastatin, was carried out in phosphate buffered solution. The terpolymers were characterized by using differential scanning calorimetry (DSC) (thermal properties), gel permeation chromatography GPC (molecular weights) and nuclear magnetic resonance (NMR) (composition and microstructure). Release profile of simvastatin was analyzed by means of UV-Vis spectroscopy. It was determined that the tested materials are useful for development of biocompatible resorbable surgical systems with the shape memory effect and controlled drug-release capability. There was no significant difference in the degradation process between the matrices without drug and with 1% of simvastatin.
EN
This paper reports development and validation of a new microemulsion liquid chromatographic (MELC) method for rapid screening of simvastatin and simvastatin acid in human plasma. Plasma samples were injected directly into the HPLC system after appropriate sample dilution with mobile phase. Separations were performed on a 4.6 mm × 150 mm, 5-µm particle, C 18 column, with UV detection at 238 nm. The mobile phase was 0.5% ( w/u ) diisopropyl ether, 1.0% ( w/u ) sodium dodecylsulphate (SDS), 4.0% ( w/v ) n -butanol, and 94.5% ( w/w ) aqueous 25 mM disodium hydrogen phosphate, pH 7.0, at a flow rate of 1 mL min -1 . The method was evaluated according to criteria stated in FDA bioanalytical method validation guidance. The unique approach applied in this paper enables direct analysis of simvastatin and simvastatin acid, so the method can be used to obtain reliable results in a rapid and simple way.
EN
Densitometric and videodensitometric methods for determination of lovastatin and simva-statin in commercially available pharmaceutical have been described. Analysis was performed using HPTLC Si F254 plates and hexane-methylethylketone (55:45 v/v) mobile phase. Densitometric detection was performed at 230 nm, and videoscanning at 254 nm. Calibration plots were constructed in the range 4-16 &mi; g per spot for both drugs. Calibration data were subjected to statistical analysis using AIC criterion. Quadratic regression was finally chosen. Active substances were extracted from tablets with methanol. Densitometric method was much more precise than videodensitometric one. However, no significant differences in the accuracy between both procedures were observed. The proposed methods can be used in routine drug analysis due to their precision, accuracy, and relatively low consumption of materials and reagents.
PL
W pracy opisano densytometryczną i wideodcnsylometryczną metodę oznaczania lowasta-tyny i simwastatyny w dostępnych na rynku polskim preparatach farmaceutycznych. Analizę przeprowadzono na płytkach HPTLC pokrytych żelem krzemionkowym z użyciem fazy ruchomej o składzie heksan-metyletylketon (55:45 v/v). Detekcję densytometryczną przeprowadzono przy długości fali 230 nm, a wideoskanowanie przy 254 nm. Krzywe kalibracyjne skonstruowano w zakresie stężeń 4-16 &mi; g na plamkę. Dane kalibracyjne zostały poddane analizie statystycznej i na podstawie kryterium AIC wybrano regresję kwadratową. Ekstrakcję z tabletek przeprowadzono metanolem. Pomiędzy obiema metodami nie stwierdzono różnic w dokładności, natomiast densy tometria odznaczała się wyraźnie lepszą precyzją. Proponowana metoda jest dokładna i precyzyjna, może być użyta w rutynowej analizie produktów leczniczych.
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