Autor: Krzek, Jan - Prolib Integro

Skocz do pozycji: 1.

Tytuł:: TLC determination of meloxicam in tablets and after acidic and alkaline hydrolysis
Autorzy:: Krzek, Jan
Starek, Małgorzata
Opis:: A simple and rapid method for separation and determination of meloxicam and its degradation products by thin-layer chromatography with densitometric detection in pharmaceutical preparations was described. The method employed TLC F254 plates as the stationary phase. The solvent system consisted of ethyl acetate : toluene : butylamine (2:2:1, v/v/v). Densitometric analysis was carried out in absorbance mode at wavelength of 297 nm. The method was validated for linearity, precision and accuracy. The limits of detection and determination were 0.96 μg per spot and 2.90 μg per spot, respectively. The drug was degraded in acidic and basic environment, at different temperatures. The degradation products were well resolved from the active substance. The HPLC-MS/MS method for the identification of degradation products of meloxicam (i.e. 5 methylthiazol- 2-ylamine and 5-(dioxide-l6-sulfanylidene)-6-methylidenecyclohexa-1,3-diene) was investigated. Because the presented method allows the efficient separation of the drug from some of its degradation products, so it can be used as a stability-indicating analysis.
Dostawca treści:: Repozytorium Uniwersytetu Jagiellońskiego

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Skocz do pozycji: 2.

Tytuł:: Densitometric determination of impurities in pharmaceuticals : part VI : determination of 4,4-bis [4-(p-chloropenyl)-4-hydro- xypiperidino] butyrophenone in haloperidol
Autorzy:: Krzek, Jan
Maślanka, Anna
Dostawca treści:: Repozytorium Uniwersytetu Jagiellońskiego

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Skocz do pozycji: 3.

Tytuł:: Spectrophotometric determination of bacitracin in bulk drug as dabsyl derivative in a range of visible light
Autorzy:: Krzek, Jan
Piotrowska, Joanna
Opis:: A fast spectrophotometric method has been developed for bacitracin identification and determination after condensation reaction with dabsyl chloride. In addition, determination of dye stability of sulfonamide derivative and identification of the molar ratio of reagents was done at various time-points. The developed method has a good linearity with very broad spectrum, correlation coefficient of r = 0.9972, good precision (RSD = 1.54 ± 0.11%), and recovery at three different levels of concentration was found between 98.33% and 103.47%. Usefulness of the method was demonstrated by positive results obtained during determination of bacitracin concentration in bulk drug.
Dostawca treści:: Repozytorium Uniwersytetu Jagiellońskiego

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Skocz do pozycji: 4.

Tytuł:: Quantification of isoxicam in the presence of related compounds by TLC-densitometry
Autorzy:: Krzek, Jan
Starek, Małgorzata
Dostawca treści:: Repozytorium Uniwersytetu Jagiellońskiego

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Skocz do pozycji: 5.

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Skocz do pozycji: 6.

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Skocz do pozycji: 7.

Tytuł:: Determination of Se(IV), Cd(II) and Pb(II) ions in homeopathic drugs by inversion voltammetry method
Autorzy:: Krzek, Jan
Kierszniewska, Anna
Opis:: The conditions for identification and quantification of Se(IV), Cd(II) and Pb(II) ions in homeopathic drugs by inversion voltammetry method with the use of EAGRAPH software were established. The studies proved that the method was of high sensitivity in established conditions. The detection limits were 0.66 μg/mL, 0.08 μg/mL and 0.12 μg/mL for Se(IV), Pb(II) and Cd(II) ions, respectively. This method was characterized by repeatability of measurements, a wide range of linearity and satisfactory percent recovery.
Dostawca treści:: Repozytorium Uniwersytetu Jagiellońskiego

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Skocz do pozycji: 8.

Tytuł:: Determination of azole antifungal medicines using zero-order and derivative UV spectrophotometry
Autorzy:: Ekiert, Radosław
Krzek, Jan
Opis:: This paper presents a new methodology of quantitative determination of seven azole antifungal medicines widely used in therapy. Analyses were performed directly by using zero-order (fluconazole), first derivative (bifonazole, clotrimazole, econazole, itraconazole, miconazole) and second derivative (ketoconazole) UV spectrophotometry. Validation of all methods confirms their proper precision (%RSD = 0.47 - 2.86), recovery (98.7 - 101.4) and linearity (r coefficient over 0,999) in concentrations under investigation. The parameters received enable the developed procedure to be used in quantitative and as auxiliary in qualitative pharmaceutical analysis.
Dostawca treści:: Repozytorium Uniwersytetu Jagiellońskiego

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Skocz do pozycji: 9.

Tytuł:: Photostability of triazole antifungal drugs in the solid state
Autorzy:: Ekiert, Radosław
Krzek, Jan
Opis:: The publication is devoted to photostability assessment of four triazole antifungal drugs: fluconazole, itraconazole, posaconazole and voriconazole. The compounds were exposed in the solid state using the whole spectrum of UV-Vis radiation. The analyses were performed using high performance thin layer chromatography (HPTLC) technique with densitometric detection. The results indicates considerable degradation of structurally similar itraconazole and posaconazole which could be clinically significant. After 72 hours of itraconazole irradiation there remain less than 25%, and 60% in case of posaconazole. To a lesser extent photodegradation concern two other compounds with a separate chemical structure: fluconazole and voriconazole. After 72 hours of irradiation there left 75% and 82% of these substances, respectively. The strict dependence between compound photostability and its chemical structure was observed.
Dostawca treści:: Repozytorium Uniwersytetu Jagiellońskiego

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Skocz do pozycji: 10.

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