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Prague, Czech Republic

Proksa B.,Zentiva
Chemical Papers | Year: 2010

This manuscript presents an overview of the research performed on Talaromyces flavus, a microorganism remarkable for its secondary metabolites with unique biological activities, enzymes applicable in the synthesis of saccharides, preparation of chiral building blocks or biotransformations, and for its application in pest biocontrol. © 2010 Institute of Chemistry, Slovak Academy of Sciences. Source

Bosutinib is a selective kinase inhibitor introduced in 2012 by Pfizer Co. for treatment of chronic myeloid leukemia. Bosutinib is widely used in medicine and basic research. Some information indicated that researchers purchasing Bosutinib from a wide range of sources may have unwittingly been using an isomer of Bosutinib instead of Bosutinib itself. The aim of the review is to describe this serious case of marketing as well as to outline possible reasons and consequences of this case. Source

Simek M.,Ustav chemie pevnych latek | Grunwaldova V.,Zentiva | Kratochvil B.,Ustav chemie pevnych latek
Chemicke Listy | Year: 2014

The particle size and shape of raw materials influence the manufacture and behavior of solid dosage forms. The most widely used methods of particle size measurement are laser diffraction and image analysis. These methods are based on different principles and measurement ranges. Only the results obtained by the same method under the same conditions can be compared. Laser diffraction is significantly faster if a validated method is known. The method is defined for every raw material to guarantee reproducibility of measurement. Image analysis is inexpensive and does not require the validated method. Shape information is easily provided by image analysis. Laser diffraction is a suitable method for routine quality control. Image analysis is an optimal technique for development of pharmaceuticals. Source

Lehnert P.,Palacky University | Pribylka A.,Palacky University | Maier V.,Palacky University | Znaleziona J.,Palacky University | And 2 more authors.
Journal of Separation Science | Year: 2013

The methods for separation of R,S-tolterodine and R,S-methoxytolterodine enantiomers using sulfated α-, β-CD and phosphated-γ-CD by CE in acidic BGE based on Tris/phosphate pH 2.5 buffer were developed. Sulfated α- and β-CD allow anodic detection while phosphated-γ-CD allows only cathodic detection of the separated enantiomers. The influence of chiral selector (CS)'s concentration as well as the influence of composition and concentration of BGE on resolutions were studied. Reversal migration order of tolterodine and methoxytolterodine enantiomers was observed, when sulfated-α- and sulfated-β-CD were used. The developed methods with all three studied CSs, were validated and compared. All proposed methods enable determination of 0.2% of S-tolterodine as an optical impurity in pills, however the method with phosphated-γ-CD provided lower detection limit, better repeatability of peak areas and migration times, and also lower consumption of CS. Developed method employing phosphated-γ-CD that was applied for the determination of optical purity of R-tolterodine in commercial pills. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Source

Dousa M.,Zentiva | Srbek J.,Zentiva | Stransky Z.,Palacky University | Gibala P.,Zentiva | Novakova L.,Charles University
Journal of Separation Science | Year: 2014

The retention behavior of several series of free α- and ω-amino acids and positional isomers of amino pentanoic acid in the hydrophilic interaction chromatography mode (HILIC) was studied. The study was carried out on three stationary phases followed by post-column derivatization with fluorescence detection in order to describe the retention mechanism of the tested amino acids. The effect of chromatographic conditions including acetonitrile content in the mobile phase, mobile phase pH (ranging from 3.5 to 6.5) and concentration of buffer in the mobile phase was investigated. The effect of the number of carbon atoms (nC) in aliphatic chains of the individual homologue of α- and ω-amino acids and the logarithm of the partition coefficient (logD) on retention was also a part of the presented study. A good correlation (r > 0.98) between the logk and logD values of amino acids or nC, respectively, was observed. The described linear relationships were subsequently applied to predict the retention behavior of individual members of the homologous series of amino acids and to optimize the mobile phase composition in HILIC. The obtained results confirmed that the retention mechanism of α-amino acids, ω-amino acids and positional isomers of amino acids was based on the logD values and the number of carbon atoms in the aliphatic chains of amino acids. The elution order of ω-amino acids and positional isomers of amino pentanoic acid was strongly dependent on the mobile phase pH in the investigated range whereas the retention factors of all α-amino acids remained essentially unchanged on all tested stationary phases. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Source

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