The Experts below are selected from a list of 27 Experts worldwide ranked by ideXlab platform
György Máté - One of the best experts on this subject based on the ideXlab platform.
-
Densitometric Determination of Some Bioactive Guanidinium Compounds Without Post-Derivatization
JPC – Journal of Planar Chromatography – Modern TLC, 2005Co-Authors: Antal Szabó, Balázs Erdélyi, Janos Salat, György MátéAbstract:In this paper we present thin layer chromatographic methods suitable for determination of bioactive guanidinium compounds, saturated Antibiotics with UV absorbance only in the extremely short wavelength region, below 200 nm. For elimination of disturbing impurities, arising mostly from binding Agents in the precoated silica gel plates, an efficient prewashing method with methanol-formic acid, 50:50 ( v/v ) was used. In this way a smooth and straight baseline was obtained in the region of measurement even if polar mobile phases had been used. Of the compounds investigated, special attention was devoted to primycin, a Macrolide Antibiotic Agent. Owing to the complexity of this Antibiotic good separation has been a real challenge. An efficient separation system, suitable for both the quality control of the end product and for monitoring the efficiency of isolation from the fermentation liquor, has been established. Further compounds containing guanidinium groups, for example streptomycin, dihydrostreptomycin, arginine, and protected arginine have also been investigated. The peaks obtained by direct evaluation were checked by a modified version of the well known Sakaguchi reaction, a selective reaction for the identification of compounds containing guanidinium groups.
-
Densitometric determination of some bioactive guanidinium compounds without post-derivatization
Journal of Planar Chromatography – Modern TLC, 2005Co-Authors: Antal Szabó, Balázs Erdélyi, Janos Salat, György MátéAbstract:In this paper we present thin layer chromatographic methods suitable for determination of bioactive guanidinium compounds, saturated Antibiotics with UV absorbance only in the extremely short wavelength region, below 200 nm. For elimination of disturbing impurities, arising mostly from binding Agents in the precoated silica gel plates, an efficient prewashing method with methanol-formic acid, 50:50 ( v/v ) was used. In this way a smooth and straight baseline was obtained in the region of measurement even if polar mobile phases had been used. Of the compounds investigated, special attention was devoted to primycin, a Macrolide Antibiotic Agent. Owing to the complexity of this Antibiotic good separation has been a real challenge. An efficient separation system, suitable for both the quality control of the end product and for monitoring the efficiency of isolation from the fermentation liquor, has been established. Further compounds containing guanidinium groups, for example streptomycin, dihydrostreptomycin...
Tatsuji Iga - One of the best experts on this subject based on the ideXlab platform.
-
Inhibitory effect of erythromycin on potassium currents in rat ventricular myocytes in comparison with disopyramide.
The Journal of pharmacy and pharmacology, 2003Co-Authors: Erika Hanada, Hisakazu Ohtani, Michiko Hirota, Noriko Uemura, Haruaki Nakaya, Hajime Kotaki, Hitoshi Sato, Yasuhiko Yamada, Tatsuji IgaAbstract:Abstract Disopyramide, a class Ia antiarrhythmic Agent, has been reported to induce torsades de pointes (TdP) associated with excessive QT prolongation in electrocardiogram (ECG), especially when concomitantly administered with erythromycin, a Macrolide Antibiotic Agent. In this study, we have evaluated the effects of erythromycin on action potential duration (APD) and potassium currents in rat ventricular myocytes in comparison with disopyramide. We have evaluated the relationship between in-vitro potassium current inhibition and in-vivo QT prolongation observed in a previous study. Action potentials and membrane potassium currents, including delayed rectifier current (I(K)) and transient outward current (I(to)), were recorded using a whole-cell patch clamp method in enzymatically-dissociated ventricular cells. Erythromycin and disopyramide prolonged APD in a concentration-dependent manner. Disopyramide (10-100 microM) and erythromycin (100 microM) led to increases in the APD at 90% repolarization level. Disopyramide reduced I(K) (IC50 = 37.2 +/- 0.17 microM) and I(to) (IC50 = 20.9 +/- 0.13 microM) while erythromycin reduced I(K) (IC50 = 60.1 +/- 0.29 microM) but not I(to). The observed prolongation of APD might be ascribed to the inhibition of potassium currents. Erythromycin produced the prolongation of APD and the inhibition of potassium currents with a lag time after addition of the drugs, which suggested that erythromycin might not reach potassium channels from outside the ventricular cells. The potency of disopyramide was almost equivalent under in-vitro and in-vivo conditions. However, potency of erythromycin in-vitro was far weaker than that in-vivo reported in a previous study, presumably due to a difference in the uptake of erythromycin into ventricular myocytes between in-vivo and in-vitro conditions. Therefore, when drug-induced risks of QT prolongation are to be evaluated, the difference of potencies between in-vitro and in-vivo should be taken into consideration.
Antal Szabó - One of the best experts on this subject based on the ideXlab platform.
-
Densitometric Determination of Some Bioactive Guanidinium Compounds Without Post-Derivatization
JPC – Journal of Planar Chromatography – Modern TLC, 2005Co-Authors: Antal Szabó, Balázs Erdélyi, Janos Salat, György MátéAbstract:In this paper we present thin layer chromatographic methods suitable for determination of bioactive guanidinium compounds, saturated Antibiotics with UV absorbance only in the extremely short wavelength region, below 200 nm. For elimination of disturbing impurities, arising mostly from binding Agents in the precoated silica gel plates, an efficient prewashing method with methanol-formic acid, 50:50 ( v/v ) was used. In this way a smooth and straight baseline was obtained in the region of measurement even if polar mobile phases had been used. Of the compounds investigated, special attention was devoted to primycin, a Macrolide Antibiotic Agent. Owing to the complexity of this Antibiotic good separation has been a real challenge. An efficient separation system, suitable for both the quality control of the end product and for monitoring the efficiency of isolation from the fermentation liquor, has been established. Further compounds containing guanidinium groups, for example streptomycin, dihydrostreptomycin, arginine, and protected arginine have also been investigated. The peaks obtained by direct evaluation were checked by a modified version of the well known Sakaguchi reaction, a selective reaction for the identification of compounds containing guanidinium groups.
-
Densitometric determination of some bioactive guanidinium compounds without post-derivatization
Journal of Planar Chromatography – Modern TLC, 2005Co-Authors: Antal Szabó, Balázs Erdélyi, Janos Salat, György MátéAbstract:In this paper we present thin layer chromatographic methods suitable for determination of bioactive guanidinium compounds, saturated Antibiotics with UV absorbance only in the extremely short wavelength region, below 200 nm. For elimination of disturbing impurities, arising mostly from binding Agents in the precoated silica gel plates, an efficient prewashing method with methanol-formic acid, 50:50 ( v/v ) was used. In this way a smooth and straight baseline was obtained in the region of measurement even if polar mobile phases had been used. Of the compounds investigated, special attention was devoted to primycin, a Macrolide Antibiotic Agent. Owing to the complexity of this Antibiotic good separation has been a real challenge. An efficient separation system, suitable for both the quality control of the end product and for monitoring the efficiency of isolation from the fermentation liquor, has been established. Further compounds containing guanidinium groups, for example streptomycin, dihydrostreptomycin...
David Zeltser - One of the best experts on this subject based on the ideXlab platform.
-
Roxithromycin-induced torsades de pointes
European journal of internal medicine, 2004Co-Authors: Dan Justo, Tamar Mardi, David ZeltserAbstract:Roxithromycin is an oral Macrolide Antibiotic Agent frequently used in the clinical setting. The risk of pro-arrhythmia during roxithromycin use has always been considered extremely remote. We describe a patient who developed prolongation of the QT interval and torsades de pointes under roxithromycin treatment.
Balázs Erdélyi - One of the best experts on this subject based on the ideXlab platform.
-
Densitometric Determination of Some Bioactive Guanidinium Compounds Without Post-Derivatization
JPC – Journal of Planar Chromatography – Modern TLC, 2005Co-Authors: Antal Szabó, Balázs Erdélyi, Janos Salat, György MátéAbstract:In this paper we present thin layer chromatographic methods suitable for determination of bioactive guanidinium compounds, saturated Antibiotics with UV absorbance only in the extremely short wavelength region, below 200 nm. For elimination of disturbing impurities, arising mostly from binding Agents in the precoated silica gel plates, an efficient prewashing method with methanol-formic acid, 50:50 ( v/v ) was used. In this way a smooth and straight baseline was obtained in the region of measurement even if polar mobile phases had been used. Of the compounds investigated, special attention was devoted to primycin, a Macrolide Antibiotic Agent. Owing to the complexity of this Antibiotic good separation has been a real challenge. An efficient separation system, suitable for both the quality control of the end product and for monitoring the efficiency of isolation from the fermentation liquor, has been established. Further compounds containing guanidinium groups, for example streptomycin, dihydrostreptomycin, arginine, and protected arginine have also been investigated. The peaks obtained by direct evaluation were checked by a modified version of the well known Sakaguchi reaction, a selective reaction for the identification of compounds containing guanidinium groups.
-
Densitometric determination of some bioactive guanidinium compounds without post-derivatization
Journal of Planar Chromatography – Modern TLC, 2005Co-Authors: Antal Szabó, Balázs Erdélyi, Janos Salat, György MátéAbstract:In this paper we present thin layer chromatographic methods suitable for determination of bioactive guanidinium compounds, saturated Antibiotics with UV absorbance only in the extremely short wavelength region, below 200 nm. For elimination of disturbing impurities, arising mostly from binding Agents in the precoated silica gel plates, an efficient prewashing method with methanol-formic acid, 50:50 ( v/v ) was used. In this way a smooth and straight baseline was obtained in the region of measurement even if polar mobile phases had been used. Of the compounds investigated, special attention was devoted to primycin, a Macrolide Antibiotic Agent. Owing to the complexity of this Antibiotic good separation has been a real challenge. An efficient separation system, suitable for both the quality control of the end product and for monitoring the efficiency of isolation from the fermentation liquor, has been established. Further compounds containing guanidinium groups, for example streptomycin, dihydrostreptomycin...
