ABSTRACT A new levofloxacin derivative using silver triflate with antibacterial activity was synthesized and characterized. The new compound has been physicochemically characterized through elemental analysis, spectroscopic and thermal methods. All correlated experimental data suggested that the levofloxacin triflate was obtained. The antibacterial activity of the new compound was tested against six Gram-positive and Gram-negative bacteria. In vitro, the new compound had similar activity to levofloxacin against Staphylococcus aureus, Escherichia coli and Klebsiella pneumoniae and very closed to the minimum inhibitory concentration values of levofloxacin against Staphylococcus aureus MRSA, Enterococcus faecalis, and Pseudomonas aeruginosa.

The present work describes the development of a capillary electrophoresis (CE) method for the chiral discrimination of amlodipine (AML) enantiomers using cyclodextrine (CD) derivatives as chiral selectors. A large number of native and derivatized, neutral and ionized CD derivatives were screened to find the optimal chiral selector; and carboximethyl-β-CD (CM-β-CD) was selected for the enantiomeric discrimination. A factorial analysis study was performed by orthogonal experimental design in which several factors were varied at the same time to optimize the separation method. The optimized method (25 mM phosphate buffer, pH = 9.0, 15 mM CM-β-CD, 15 ºC, + 25 kV, 30 mbar/1 second, detection wavelength 230 nm) was successfully applied for the baseline separation of AML enantiomers within 5 minutes. Successful validation and application of the proposed CE method suggest its routine use in enantioselective control of AML in pharmaceutical preparations.

ABSTRACT Enantioseparation of nine extensively used chiral pharmaceutical substances from different pharmacological classes and with different structural characteristics has been investigated by capillary zone electrophoresis using Captisol® (sulfobuthylether-β-cyclodextrin sodium salt) as chiral selector. The influence on the chiral separation of several parameters including pH and concentration of the background electrolyte, chiral selector concentration, applied voltage, system temperature and injection parameters were studied and optimized in order to obtain increased chiral resolution and shorten analysis time. The results were compared with those obtained with native and derivatized neutral cyclodextrins (β-cyclodextrin and hydroxypropryl-β-cyclodextrin). All model molecules were resolved using Captisol® as chiral additive and optimized electrophoretic conditions, proving the efficiency of this anionic derivative of β- cyclodextrin as chiral selector in capillary electrophoresis.

Differences between the pharmaceutical activity among the enantiomers of sotalol are well known, as R-sotalol and S-sotalol have similar antiarrythmic activities but only the R-enantiomer exhibits β-blocking activity. In this study capillary zone electrophoresis was used for the enantiomeric separation of sotalol using different native and derivatized; neutral and charged; cyclodextrines as chiral selectors. The effects of pH value and composition of the background electrolyte, capillary temperature, running voltage and injection parameters have been investigated. The results showed that only the randomly methylated β-cyclodextrine gave a baseline enantiomeric separation under the optimized conditions; chiral interactions being observed also for hydroxypropyl-β-CD and sulfobutyl ether-β-CD. The analytical parameters of the optimized method were verified and the migration order of the two enantiomers was established.

Este trabalho descreve o desenvolvimento de um método simples de eletroforese capilar (EC) para determinação simultânea dos três derivados mais frequentemente usados da fluoroquinolona: ciprofloxacina, norfloxacina e ofloxacina. Devido às características estruturais e físico-químicas muito semelhantes, ciprofloxacina e norfloxacina não podem ser separadas pelo método clássico de eletroforese capilar de zona (CZE). Suas separações podem ser resolvidas usando cromatografia eletrocinética micelar (MEKC), adicionando um surfactante aniônico à solução-tampão. A eficiência da separação pode ser intensificada através da otimização de parâmetros analíticos. Um método rápido e confiável foi desenvolvido, e os melhores resultados foram obtidos usando uma solução-tampão contendo tetraborato de sódio 25 mmol L-1, dodecilsulfato de sódio 100 mmol L-1 e metanol 5% como modificador orgânico.

This work describes the development of a simple capillary electrophoresis (CE) method for simultaneous determination of the three most frequently used fluoroquinolone derivatives: ciprofloxacin, norfloxacin and ofloxacin. Due to very similar structural and physicochemical characteristics, ciprofloxacin and norfloxacin cannot be separated by the classic method of capillary zone electrophoresis (CZE). Their separations can be solved using micellar electrokinetic chromatography (MEKC), by adding an anionic surfactant to the buffer solution. The efficiency of the separation can be enhanced through the optimization of analytical parameters. A fast reliable method was developed, and the best results were obtained using a buffer solution containing 25 mmol L-1 sodium tetraborate, 100 mmol L-1 sodium dodecyl sulphate and 5% methanol as organic modifier.