114 research outputs found
Treatment of early hepatic artery complications after adult liver transplantation: a single center experience
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Downstaging of hepatocellular carcinoma with radiofrequency ablation on the Hungarian liver transplantation waiting list: Early results and learned lessons
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Novel spectrophotometric method for determination of cinacalcet hydrochloride in its tablets via derivatization with 1,2-naphthoquinone-4-sulphonate
This study represents the first report on the development of a novel spectrophotometric method for determination of cinacalcet hydrochloride (CIN) in its tablet dosage forms. Studies were carried out to investigate the reaction between CIN and 1,2-naphthoquinone-4-sulphonate (NQS) reagent. In alkaline medium (pH 8.5), an orange red-colored product exhibiting maximum absorption peak (λmax) at 490 nm was produced. The stoichiometry and kinetic of the reaction were investigated and the reaction mechanism was postulated. This color-developing reaction was employed in the development of a simple and rapid visible-spectrophotometric method for determination of CIN in its tablets. Under the optimized reaction conditions, Beer's law correlating the absorbance with CIN concentration was obeyed in the range of 3 - 100 ÎŒg/ml with good correlation coefficient (0.9993). The molar absorptivity (Δ) was 4.2 Ă 105 l/mol/cm. The limits of detection and quantification were 1.9 and 5.7 ÎŒg/ml, respectively. The precision of the method was satisfactory; the values of relative standard deviations (RSD) did not exceed 2%. No interference was observed from the excipients that are present in the tablets. The proposed method was applied successfully for the determination of CIN in its pharmaceutical tablets with good accuracy and precisions; the label claim percentage was 100.80 - 102.23 ± 1.27 - 1.62%. The results were compared favorably with those of a reference pre-validated method. The method is practical and valuable in terms of its routine application in quality control laboratories
Spectrophotometric and HPLC determination of deflazacort in pharmaceutical dosage forms
Novi analitiÄki pristup sa smanjenom potroĆĄnjom organskih otapala u spektrofotometrijskoj analizi temeljenoj na prijenosu naboja: Primjena u analizi nekih antihipertenziva
The present study describes the development of a novel analytical approach that can reduce by 50-fold the consumption of organic solvents in the charge transfer (CT)-based spectrophotometric analysis. The proposed approach employed 96-microwell assay plates for carrying out the reaction. The CT reaction between the electron-donating analyte and electron-accepting reagent was performed in microwells (200-”L of organic solvent) and the color signals were measured with a microwell-plate reader. Optimum conditions for the proposed approach were established for two antihypertensive drugs, namely ramipril (RML) and lisinopril (LSL) as model compounds for the electron-donating analytes, and 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) as a -electron acceptor. Under the optimum conditions, Beerâs law was obeyed in the concentration range of 6â100 and 6â60 g mL1 for RML and LSL, respectively. The limits of detection were 0.97 and 1.10 g mL1 for RML and LSL, respectively. The precision of the methods was satisfactory; the values of relative standard deviations did not exceed 1.1 %. The proposed approach was successfully applied to the analysis of pharmaceutical dosage forms with good accuracy and precision. The results were comparable with those of the reported methods. The approach described herein is of great practical value in pharmaceutical analysis because it reduces the exposure of analysts to the toxic effects of organic solvents, lowers the analysis cost by 50-fold, and it has a high throughput property. Although the approach was validated for RML and LSL, the same methodology could be used for any electron-donating analyte for which a CT-reaction can be performed.U radu je opisan razvoj novog analitiÄkog pristupa koji 50 puta smanjuje potroĆĄnju organskih otapala u spektrofotometrijskoj analizi na bazi prijenosa naboja (CT). PredloĆŸena metoda koristi ploÄe s 96 jaĆŸica za izvoÄenje analize. CT reakcije izmeÄu elektron-donora i elektron-akceptora izvodi se u jaĆŸicama s 200-”L organskog otapala. Promjene boje mjere se pomoÄu posebnog mikroÄitaÄa za ploÄe s jaĆŸicama. OdreÄeni su optimalni uvjeti za dva antihipertenzivna lijeka, ramipril (RML) i lizinopril (LSL) koji su upotrebljeni kao modelni spojevi za elektron-donorske analite, i 2,3-diklor-5,6-dicijano-1,4-benzokinon (DDQ) kao -elektronski akceptor. U optimalnim uvjetima Beerov zakon je vrijedio u koncentracijskom podruÄju 6â100 i 6â60 g mL1 za RML, odnosno LSL. Granice detekcije bile su 0,97 i 1,1 g mL1 za RML, odnosno LSL. Preciznost metode bila je zadovoljavajuÄa, a relativna standardna devijacija bila je manja od 1,1 %. PredloĆŸena metoda uspjeĆĄno je primijenjena za analizu doziranih farmaceutskih pripravaka koji sadrĆŸe ispitivane lijekove, uz dobru toÄnost i preciznost. Rezultati predloĆŸene metode usporedivi su s rezultatima poznatih metoda. Postupak opisan u ovom radu vrlo je praktiÄan: analitiÄari su manje izloĆŸeni toksiÄnim uÄincima organskih otapala, troĆĄkovi analize smanjeni su 50 puta, a takoÄer ju odlikuje visoka propusnost. Iako je postupak validiran za RML i LSL, ista metoda moĆŸe se upotrijebiti za elektron-donirajuÄi analit koji ulazi u CT reakciju
Integrated calcareous nannofossil and ammonite data from the upper Barremianâlower Albian of the northeastern Transdanubian Range (central Hungary): Stratigraphical implications and consequences for dating tectonic events
Late Triassic platform, slope and basin deposits in the Pilis Mountains, Transdanubian Range, Hungary
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