National Repository of Grey Literature 109 records found  beginprevious32 - 41nextend  jump to record: Search took 0.00 seconds. 
Utilization of statistical approach in development of HPLC methods
Vymyslický, Filip ; Křížek, Tomáš (advisor) ; Kozlík, Petr (referee)
The aim of this diploma thesis was to develop a systematic procedure for the development of HPLC methods using the design of experiments. The system was developed based on the development of three HPLC methods for the determination of the purity of active substances using the design of experiments approach. The HPLC method for determining the purity of esomeprazole was selected to develop the systematic process for the development of HPLC methods by statistical approach. Experimental space was explored to find more suitable separation conditions. The second method used to develop the systematic procedure was the method for determining the purity of bisoprolol. This method was converted to a column of smaller size and the composition of the aqueous part of mobile phase was modified compared with the original pharmacopoeial method. Experimental space was explored to find more suitable separation conditions using the design of experiments. Last the method for determining the purity of risperidone was chosen. The composition of the aqueous part of mobile phase was changed in contrast to the original pharmacopoeial method. Experimental space was explored to find more suitable separation conditions using the design of experiments. For all studied HPLC methods, the values of the monitored chromatographic...
Analysis of active pharmaceutical ingredient vemurafenib by LC
Filounová, Barbora ; Kozlík, Petr (advisor) ; Křížek, Tomáš (referee)
The aim of this work was to develop and optimize liquid chromatography method with spectrophotometric detection applicable to assay and purity of vemurafenib in solid dosage form and perform its stability study. The optimized separation conditions consisted of Poroshell HPH-C18 (3 × 100 mm, 2.7 μm) column tempered at 30 žC, mobile phase composed of 10 mM ammonium phosphate, pH 3,0/acetonitrile. Flow rate was set at 0.6 mL/min and gradient elution was performed. Detection wavelength was 250 nm. The calibration curve of vemurafenib was constructed in the concentration range 0.4 - 1.2 mg/mL. Limit of detection was 5.0 µg/mL and limit of quantitation was 16.5 µg/mL. Stability and stress tests of vemurafenib were performed under several conditions: Heat (80 žC), heat combined with humidity (80 žC/75 % relative humidity), hydrochloric acid (0,1 M), sodium hydroxide (0,1 M) and hydrogen peroxide (3% and 0,3% solution). The significant degradation of vemurafenib was observed under acid condition. Vemurafenib also degradated under oxidation condition. No degradation was observed under base condition and under heat and heat combined with humidity. Degradation of vemurafenib was not effected by tested excipients. Judging based on experiments vemurafenib is stable from the point of view of chemical stability.
The Preparation and the Characterization of the Cationic Liposomes Carrying New Immunoadjuvant.
Houšť, Jiří ; Nesměrák, Karel (advisor) ; Kozlík, Petr (referee)
The aim of this diploma thesis was preparation, characterization and determination of encapsulation efficiency of the cationic liposomes composed of dimethyldioctadecylammonium bromide (DDAB) and cholesterol carrying new drug MT05 with an immunoadjuvant effect. The influence of the temperature of sonication bath and the influence of the volume of liposomal suspension on the average size of liposomes and their polydispersity index was monitored. The most effective liposome preparation by sonication bath was at temperature of 60 řC. The volume of liposomes undergoing sonication did not influence the resulting values of the average size of liposomes and their polydispersity index. The time of sonication time was 6 hours and could be shortened by using sonication bath with higher output. The determination of encapsulation efficiency was carried out in three separated experiments by HPLC-MS/MS. The encapsulation efficiency of the cationic liposomes was 30.1 ± 8.5 % in the first experiment, 43 ± 25 % in the second, and 32 ± 25 % in the third. The amount of DDAB was determined only in the liposomes prepared in the third experiment. The amount of DDAB in the purified liposomes was 78.9 ± 3.7 % in the first replicate, 65.4 ± 1.8 % in the second and 53.8 ± 1.4 % in the third. The actual molar ratio of MT05...
Analysis of degradation of substances of historical pharmaceutical preparations
Vašíčková, Pavla ; Nesměrák, Karel (advisor) ; Kozlík, Petr (referee)
The aim of this thesis is the analysis of transformations of the composition of pharmaceutical preparations from the years 1930-1997. The alkaloids and opium alkaloids are active substances of these pharmaceutical preparations. Pharmaceutical preparations were in form of tablet and injection solution. The presence of active compounds and their degradation products were detected using RP-HPLC with spectrometric detection. The MS/MS fragmentation pathways of compounds found were proposed. The high stability of some active substances was proved (codeine, ethylmorphine and theobromine) while some other compounds were completely decomposed.
Validation of LC-MS method and monitoring of pharmaceuticals in water samples.
Molnárová, Lucia ; Bosáková, Zuzana (advisor) ; Kozlík, Petr (referee)
Occurrence, accumulation and subsequent fate of pharmaceuticals in environment currently represent a very actual topic. Worldwide, thousands of tons of pharmaceutical substances are consumed every year. A large portion of pharmaceuticals is, in unchanged or metabolized forms, disposed via sewage systems and wastewater treatment plants. Considering the fact that wastewater treatment processes are not able to completely eliminate all active substances or their metabolites, pharmaceuticals are systematically washing out into the water system and increasingly contaminate the ground and surface waters. The problematics of continuous control and progressive elimination of pharmaceutical residues from environment are still not completely solved. Thus, the development and availability of accurate and fast commercial analyses are highly desired. The aim of this diploma thesis was the optimization and validation of multi-residue UHPLC- MS/MS analytical method designated for the determination of 52 pharmaceuticals in drinking and waste waters. The work was carried out in laboratories of ALS Czech Republic. An analytical method was subsequently used for monitoring of pharmaceuticals in both drinking and waste waters, as well as for the determination of efficiency of removing these compounds within the...
Quantification of procalcitonin in human serum by affinity surfaces and mass spectrometry
Dvořák, Josef ; Pompach, Petr (advisor) ; Kozlík, Petr (referee)
Sepsis is a worldwide health condition. It is caused by disproportionatly large immunity system response for patogene presence. Fast and accurate diagnosis of sepsis can make difference between life and death. For clinical diagnosis of sepsis is used serum protein procalcitonin (PCT) as biomarker. Procalcitonin concentration level in patient bloodstream increases up to thousand times in short time period. Severity of sepsis can be determined by correlation with its concentration in bloodstream. To determine PCT level in patient bloodstream a broad variety of specialized instrument is used. All methods have same principle of measurement - PCT-antibody interaction. Procalcitonin level is then quantified by calibration curve method. During these measurements non-specific protein-antibody interactions can occur and distort the quantification of PCT level. Mass spectrometry due to its properties comes into consideration as an alternative method, that can be used for PCT determination. Aim of this diploma thesis was in situ enrichment of PCT on surface modified affinity carriers with immobilized antibody against PCT. These carriers are compatible with matrix assisted laser desorption/ionization time of flight mass spectrometry. Mass spectrometry provides mass spectrum, where PCT and other signals...
Characterization of novel stationary phase in hydrophilic interaction liquid chromatography
Kadlecová, Zuzana ; Kalíková, Květa (advisor) ; Kozlík, Petr (referee)
The aim of this diploma thesis is detailed characterization of new diol-based column, i.e. Torus DIOL designed for supercritical fluid chromatography, in hydrophilic interaction liquid chromatography. This stationary phase contains diol ligands bonded on BEH ("bridged ethylene hybrid") particles. The BEH sorbent is more stable at high pH, pressure and temperature than conventional silica sorbents. Five fluorinated pesticides were successfully separated on Torus DIOL column. Retention mechanism and effect of different parameters were tested by analysis of small polar compounds (nucleobases, uridine and its derivatives, acidic, neutral and basic compounds). Both partitioning of analytes between an aqueous layer deposited on the surface of the stationary phase and the mobile phase and adsorption of analytes on the stationary phase participate in the retention mechanism. Effect of the mobile phase aqueous part pH was investigated with the following buffering solutions: formic acid (pH = 2.1), 10mM ammonium acetate (pH = 4.7 and pH = 9.5). Obtained results showed that aqueous part pH significantly affects retention of acidic compounds according to their pKA values. Retention of all tested analytes on Torus DIOL column slightly increased with increasing ionic strength of mobile phase. The retention...
Use of comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometric detection for metabolomic analysis of Gloeophyllum trabeum fungus
Kuchler, Ondřej ; Sobotníková, Jana (advisor) ; Kozlík, Petr (referee)
Fungus Gloeophyllum trabeum (Agaricomytes: Gloeophyllates) is a brown rot wood-decay fungus which produces a vast spectrum of volatile secondary metabolites. Scientific publications state, that one of the metabolites produced by G. trabeum, can be the substance (3Z,6Z,8E)-dodecatrien-1-ol. This chemical substance is also the main component of trail-following pheromone of Rhinotermitidae termite family. In this diploma thesis, I was trying to verify whether various species of G. trabeum are in fact capable of producing the substance (3Z,6Z,8E)-dodecatrien-1-ol. I was also focusing on the effects of saccharides, present in nutrient solutions, on quantitative and qualitative change in composition of volatile secondary metabolites produced by G. trabeum. The saccharides I used for my research were - maltose, fructose, sucrose, xylose, and mannose. The analysis was made by using comprehensive two-dimensional gas chromatography separation technique with time-of-flight mass spectrometric detection (GC×GC-TOFMS). During my research I discovered that one of obtained species of G. trabeum can produce substance (3Z,6Z,8E)-dodecatrien-1-ol, but only under specific conditions. It is produced when cultivating on Petri dishes on agar - cellulose growth media. The measurement was further validated by...
Determination of testosterone esters in injectable dosage form by HPLC-DAD
Folprechtová, Denisa ; Kozlík, Petr (advisor) ; Kubíčková, Anna (referee)
Anabolic steroids are currently very controversial issue not only for its therapeutic use but especially because of the illegal abuse in the sport branch. The aim of this thesis was to develop a rapid, selective, effective and simple method of high performance liquid chromatography suitable for the determination of anabolic steroids in injectable dosage form. The analyzed sample of pharmaceutical product Sustamed contained four testosterone esters: testosterone propionate, testosterone phenylpropionate, testosterone isocaproate and testosterone decanoate. Optimized HPLC-DAD conditions suitable for determination of the selected testosterone esters were as follows: core-shell column Poroshell HPH-C18 (3.0 x 100 mm, 2.7 mm), mobile phase consisted of 10mmol/l ammonium acetate, pH 4.5 and acetonitrile, gradient elution was used. The column was thermostated at 50 řC, injection volume was 1 µl, flow rate was set at 1ml/min and UV detection at 240 nm. Total analysis time was 6 minutes. Key words anabolic steroids, testosterone esters, HPLC-DAD
Development of a novel method for nucleotide pool analysis in bacterial cells
Zborníková, Eva ; Rejman, Dominik (advisor) ; Pacáková, Věra (referee) ; Kozlík, Petr (referee)
(EN) This thesis deals with the determination of nucleotides in bacterial cells. Nucleotides play crucial role in most of the metabolic pathway. Determining their concentrations could give us important clues about the influence of internal and external conditions on the bacterial metabolism. Previously published papers dealing with the analysis of nucleotides and other intracellular metabolites can be divided into two groups according to the analytical approach: a) metabolomic approach and b) targeted approach dealing with narrow group of target analytes. In the case a) most authors use the state-of-the-art LC-MS/MS technique, whereas in the case b) robust UV detection coupled mainly to IP-LC is widely used. The aim of this study was to combine both approaches to obtain a method for routine analysis that would take advantages of mass detection, such as sensitivity and selectivity, while avoiding the need of demanding optimization of MS/MS transitions and expert service. The main purpose of the newly developed HILIC-MS method is its universal applicability in most biological and biochemical laboratories.

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