Simultaneous determination of amoxicillin and clavulanic acid in pharmaceutical preparations by capillary zone electrophoresis

O ácido clavulânico acentua o espectro antibacteriano de amoxicilina, tornando a maioria dos isolados produtores de β-lactamase sensíveis ao fármaco. Desenvolveu-se um método rápido, simples e eficiente de electroforese capilar (EC) para a determinação simultânea de amoxicilina e de ácido clavulânico a partir de misturas complexas. Usando tetraborato de sódio 25 mM como electrólito em pH de 9,30, voltagem aplicada de + 25 kV, em sistema a 25 ° C e determinação por UV a 230 nm, a foi bem-sucedida a separação simultânea de amoxicilina e ácido clavulânico em, aproximadamente, 2 minutos. O desempenho analítico do método foi avaliado em termos de reprodutibilidade, precisão, exatidão e linearidade. O método analítico otimizado foi aplicado para a determinação dos dois analitos em associação, a partir de preparações farmacêuticas comerciais. Este método de EC é rápido, barato, eficiente e ecologicamente correto, quando comparado aos métodos de cromatografia líquida de alta eficiência mais frequentemente descritos na literatura.Clavulanic acid enhances the antibacterial spectrum of amoxicillin by rendering most β-lactamase producing isolates susceptible to the drug. A fast, simple and efficient capillary electrophoresis method was developed for the simultaneous determination of amoxicillin and clavulanic acid from complex mixtures. Using a 25 mM sodium tetraborate as background electrolyte at a pH of 9.30, + 25 kV applied voltage, 25 °C system temperature, UV determination at 230 nm; we succeeded in simultaneous separation of amoxicillin and clavulanic acid in approximately 2 minutes. The analytical performance of the method was evaluated in terms of reproducibility, precision, accuracy, and linearity. The optimized analytical method was applied for the determination of the two analytes from combined commercial pharmaceutical preparations. This CE method is fast, inexpensive, efficient, and environmentally friendly when compared with the more frequently used high performance liquid chromatography methods described in the literature

CHIRAL SEPARATION OF CETIRIZINE ENANTIOMERS BY CYCLODEXTRIN MEDIATED CAPILLARY ELECTROPHORESIS

Chiral separation cetirizine, a second generation H1 antagonist was studied by cyclodextrine (CD) mediated capillary electrophoresis. The influence on the separation of several parameters including pH and concentration of the background electrolyte (BGE), CD type and concentration, applied voltage and temperature were studied and the electrophoretic and analytic parameters were optimized. The best conditions for the chiral separation were obtained using 25mM disodium hydrogeno-phosphate – 25mM sodium didydrogeno-phosphate (1:1) as BGE, 5mM sulfobuthyl ether- β-CD as chiral selector, a voltage of + 20kV, temperature of 20°C, injection pressure/time of 50mbar/ 1sec, UV detection at 230nm. The analytical performance of the method was evaluated. The proposed method was successfully applied to the enantioselective assay of cetirizine in pharmaceutical formula-tions. CE proved to be a rapid, specific, reliable and cost-effective method for the chiral separation of cetirizine enantiomers and can be useful for laboratories performing routine analysis.

Development of a generic method for the determination of protonpump inhibitors by capillary zoneelectrophoresis

A generic capillary zone electrophoresis method was developed for the analysis of four proton pump inhibitors: omeprazole, pantoprazole, lansoprazole and rabeprazole. During preliminary analysis screening of phosphate buffers at different pH levels was performed, in order to determine the optimum pH domain suitable for the simultaneous determination of all studied compounds. A face centered central composite design was employed for the optimization of separation conditions. The effect of buffer concentration, pH and applied voltage was studied; resolution between peaks and migration time of the last compound were considered as responses. Other factors as system temperature, injection parameters, capillary length, were held constant during the optimization process. The optimized conditions consisted of 40mM phosphate background electrolyte at pH 5.0, +25 kV applied voltage and 20 °C temperature. The migration order of the analytes was as follows: rabeprazole, omeprazole, lansoprazole and pantoprazole. Full resolution of all analytes was achieved within 9 minutes. The method was validated and proved to be suitable in terms of repeatability, sensitivity, linearity, accuracy and robustness. Determinations from commercially available pharmaceutical formulation were performed for omeprazole; good reproducibility and recovery were obtained

TAXONOMICAL AND CHOROLOGICAL NOTES 1 (1–19)

Th e fi rst part of the newly launched series includes miscellaneous new records from fungi to vascular plants. New chorological records of 14 fungi taxa are provided here: two new (Hypoxylon ticinense and Amylostereum laevigatum) and one confi rmed (Sarcodontia crocea) for Hungary; one new for Kiskunság and Bükk Mts (Pholiota squarrosoides); fi ve new for Vértes Mts (Arrhenia rickenii, Dentipellis fr agilis, Entoloma zuccherellii var. pluteisimilis, Gomphidius roseus, Leucoagari cus ionidicolor) and partly Central Hungary; four new for Sopron Mts (Agaricus bohusii, Amanita vittadinii, Hericium erinaceus and Leccinum variicolor); and two new for Neusiedl Hills (Gomphidius roseus and Polyporus umbellatus). Records of one moss (Anacamptodon splachnoides) new for Cserhát and Cserehát Mts are provided here. New chorological records of two vascular plants are provided: one taxon (Crataegus rosaeformis subsp. curvisepala) new for Hernád Valley and NE Hungary; one (Epipactis leptochila subsp. neglecta) new for the Börzsöny Mts. Two new combinations in genus Chamaecytisus are proposed here (Chamaecytisus supinus subsp. aggregatus and subsp. pannonicus). The present paper includes also the revision of the occurrence of Calamag rostis villosa in Hungary and concludes that it has been extinct in the country

Simple and choice reaction times are prolonged following extracorporeal circulation : a potential method for the assessment of acute neurocognitive deficit

Cognitive deficit related to open heart surgery came into the focus of interest according to professional and social expectations. The negative effects on quality of life and the large number of involved patients emphasize its investigation. The bed-side measurement of simple and choice reaction time (sRT and cRT) has the objectivity of cortical evoked potential analysis; however there is no need for EEG instrumentation and laboratory. This is a functional assessment similarly to neuropsychological tests, but requires significantly shorter time, and is less demanding for the patient. We found a statistically significant positive correlation of sRT and cRT elongation and perfusion time. At the same time there were no statistically significant changes of mean sRT and cRT values before (sRT: 208±54 s, cRT: 369±59 s) and after (sRT: 229±67 s, cRT: 392±105 s) the surgery probably due to the inhomogeneous patient population. The weak correlation (coefficients: 0.1418-0.8484) for sRT and cRT changes as a function of perfusion time confirm the presence of other factors of postoperative brain damage. The investigated bed-side test is clinically feasible, simple and can be completed within 30 minutes. Further studies are encouraged to compare above method to other tests in a larger, stratified cardiac surgery populatio

Assembly of Schizosaccharomyces cryophilus chromosomes and their comparative genomic analyses revealed principles of genome evolution of the haploid fission yeasts

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Chiral separation of lansoprazole and rabeprazole by capillary electrophoresis using dual cyclodextrin systems

Novel capillary electrophoresis methods using CDs as chiral selectors were developed andvalidated for the chiral separation of lansoprazole and rabeprazole, two proton pump in-hibitors. Fourteen different neutral and anionic CDs were screened at pH 4 and 7 in thepreliminary analysis. Sulfobutyl-ether-␤-CD with a degree of substitution of 6.5 and 10 atneutral pH proved to be the most suitable chiral selector for both compounds. Various dualCD systems were also compared, and the possible mechanisms of enantiomer separationwere investigated. A dual selector system containing sulfobutyl-ether-␤-CD degree of sub-stitution 6.5 and native ␥ -CD proved to be the most adequate system for the separations.Method optimization was carried out using an experimental design approach, performingan initial fractional factorial screening design, followed by a central composite design toestablish the optimal analytical conditions. The optimized methods (25 m M phosphatebuffer, pH 7, 10 mM sulfobutyl-ether-␤-CD/20 mM ␥ -CD, +20 kV voltage; 17°C tempera-ture; 50 mbar/3 s injection, detection at 210 nm for lansoprazole; 25 mM phosphate buffer,pH 7, 15 mM sulfobutyl-ether-␤-CD/30 mM ␥ -CD, +20 kV voltage; 18°C temperature;50 mbar/3 s injection, detection at 210 nm for rabeprazole) provided baseline separationfor lansoprazole (Rs= 2.91) and rabeprazole (Rs= 2.53) enantiomers with favorable migra-tion order (in both cases the S-enantiomers migrates first). The optimized methods werevalidated according to current guidelines and proved to be reliable, linear, precise, andaccurate for the determination of 0.15% distomer as chiral impurity in dexlansoprazoleand dexrabeprazole samples

Az iszkémiás és posztiszkémiás vaszkuláris és kardiorespiratorikus károsodások tanulmányozása = Investigation of apparent injury in the vascular and cardiorespiratory system due to ischemia and reperfusion

((1) A szívhipertrófiát irányító GATA-4 transzkripciós faktort a mitogén-aktiválta protein kinázok (p38, ERK) aktiválják mechanikai feszítés során. (2) Kamrai falfeszülés az endogén endothelin-1 és az angiotenzin II révén váltja ki a BNP expressziójának fokozódását. (3) Az endogén ouabain-szerű anyag szerepet játszik az ANP bal kamrai génexpressziójának szabályozásában. (4) A nukleáris faktor-kappaB transzkripciós faktor gátlása kivédi a bal kamrai remodellinget annak előrehaladott fázisában. (5) A szívizom-kontraktilitás szabályozásában döntő szerepet játszanak a mitogén aktiválta protein kinázok. (6) Viabilitás, coronária occlusios idő okozta bal kamra funkció változás vizsgálata MRI-vel. Az occlusios idő 45 és 90 perc között változtatvan proporcionálisan rontotta a bal kamra funkciót, mely mögött okként az arányos infarctus méret áll. (7) Humán mitrokondriumok nem termelnek relevans mennyiségű nitrogén oxidot iszkémiás szívbetegekben. (8) A flavonoid szupplementáció előnyös hatású krónikus obstruktív tüdőbetegségben. (9) Invazív módon validáltuk az artériás stifness meghatározására szolgáló non-invazív Arteriográf készüléket. (10) Jellemeztük a szérum asszimmetrikus dimetil-arginin változását katéteres revascularizatios eljáráson átesett betegeknél. (11) A poli-ADP-ribóz polimeráz enzim gátlása javítja a bal kamrai funkciót akut és krónikus experimentális szívelégtelenségben. (12) A szívritmus variabilitás vizsgálatára hatékony elemző rendszert fejlesztettünk ki. | (1) Our results suggest that the prohypertrophic transcription factor GATA-4 is activated by mitogen-activated protein kinases (p38, ERK) in response to mechanical stretch. (2) Stretch-induced activation of B-type natriuretic peptid gene expression is regulated by endogenous endothelin-1 and angiotensin II. (3) Adrenal-derived endogenous ouabain-like compound is involved in the activation of atrial natriuretic peptide in the left ventricle. (4) Inhibition of nuclear factor kappa-B attenuates severe left ventricular remodeling. (5) Mitogen-activated protein kinases play pivotal role in the regulation of myocardial contractility. (6) MRI study of LV function: dependence on coronary occlusion time and viability. Occlusion time between 45 and 60 minutes induced larger infarct and consequent heart failure proportionally. (7) Human heart mitochondria do not produce physiologically relevant quantities of nitric oxide. (8) Dietary flavonoids are beneficial in chronic obstructive pulmonary disease. (9) A new, oscillometric, portable device for measuring augmentation index and aortic pulse wave velocity (Areteriograph) has been validated invasively. (10) The response of asymetric dimethylarginine levels to stent placement has been characterized in patients with coronary heart disease. (11) Inhibition of poly(ADP-ribose) polymerase improves cardiac function in acute and chronic heart failure. (12) A data analysis system has been developed for analysis of heart rate variability

Determination of Chiral Impurity of Naproxen in Different Pharmaceutical Formulations Using Polysaccharide-Based Stationary Phases in Reversed-Phased Mode

A novel, validated, reversed-phase (RP), chiral high performance liquid chromatography (HPLC) method was developed for the enantiopurity control analysis of naproxen, a frequently used non-steroidal anti-inflammatory agent using polysaccharide-type chiral stationary phase (CSP). In the screening phase of method development, seven columns were tested in polar organic (PO) mode using mobile phases consisting of 0.1% acetic acid in methanol, ethanol, 2-propanol, and acetonitrile. Enantiorecognition was observed only in five cases. The best enantioseparation was observed on a Lux Amylose-1 column with 0.1% (v/v) acetic acid in ethanol with a resolution (Rs) of 1.24. The enantiomer elution order was unfavorable, as the distomer eluted after the eutomer. When the ethanolic mobile phase was supplemented with water, enantiomer elution order reversal was observed, indicating a difference in the enantiorecognition mechanism upon switching from PO to RP mode. Furthermore, by changing ethanol to methanol, not only lower backpressure, but also higher resolution was obtained. Subsequent method optimization was performed using a face-centered central composite design (FCCD) to achieve higher chiral resolution in a shorter analysis time. Optimized parameters offering baseline separation were as follows: Lux Amylose-1 stationary phase, thermostated at 40 °C, and a mobile phase consisting of methanol:water:acetic acid 85:15:0.1 (v/v/v), delivered with 0.65 mL/min flow rate. Using these optimized parameters, a Rs = 3.21 ± 0.03 was achieved within seven minutes. The optimized method was validated according to the ICH guidelines and successfully applied for the analysis of different pharmaceutical preparations, such as film-coated tablets and gel, as well as fixed-dose combination tablets, containing both naproxen and esomeprazole