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Introduction
Publications
Publications (74)
Nilotinib is a selective tyrosine-kinase inhibitor approved for the treatment of chronic myeloid leukemia. It is poorly soluble in aqueous media and has a low oral bioavailability. Nilotinib encapsulation into yeast glucan particles (GPs) was investigated in this work as a means of increasing bioavailability. The amorphization of nilotinib in GPs r...
Introduction: Rheumatoid arthritis (RA) is a chronic autoimmune disease with unknown cause. It mainly affects joints and, without proper treatment, negatively impacts their movement, causes painful deformities, and reduces the patients' quality of life. Current treatment options consist of various types of disease-modifying antirheumatic drugs (DMA...
The present study investigates the physicochemical properties and stability of a novel lipid-based formulation—surfactant-enriched oil marbles containing abiraterone acetate. While the biopharmaceutical performance of this formulation has been reported recently, this study aims to fill the gap between a promising in vivo performance and industrial...
Saccharides form one of the major constituents of biological macromolecules in living organisms. Many biological processes including protein folding, stability, immune response and receptor activation are regulated by glycosylation. In this work, we optimized a capillary electrophoresis method with capacitively coupled contactless conductivity dete...
Liposomes are nowadays a matter of tremendous interest. Due to their amphiphilic character, various substances with different properties can be incorporated into them and they are especially suitable as a model system for controlled transport of bioactive substances and drugs to the final destination in the body; for example, COVID-19 vaccines use...
The alarming rise of bacterial antibiotic resistance requires the development of new compounds. Such compounds, lipophosphonoxins (LPPOs), were previously reported to be active against numerous bacterial species, but serum albumins abolished their activity. Here we describe the synthesis and evaluation of novel antibacterial compounds termed LEGO-L...
This work deals with newly developed poly(styrene-divinylbenzene-methacrylic acid) monolithic columns for capillary electrochromatographic and capillary liquid chromatographic separations of low-molecular-weight organic compounds. The influence of the polymerization time on chromatographic properties of prepared monolithic capillary columns was stu...
Pythium oligandrum, strain M1, is a soil oomycete successfully used as a biological control agent (BCA), protecting plants against fungal, yeast, and oomycete pathogens through mycoparasitism and elicitor-dependent plant priming. The not yet described Pythium strains, X42 and 00X48, have shown potential as BCAs given the high activity of their secr...
Analysis of protein glycosylation is challenging due to micro- and macro-heterogeneity of the attached glycans. Hydrophilic interaction liquid chromatography (HILIC) is a mode of choice for separation of intact glycopeptides, which are inadequately resolved by reversed phase chromatography. In this work, we propose an easy-to-use model to predict r...
The feasibility of on‐capillary derivatization of saccharides by aromatic amine‐based fluorescent labeling agents was tested. To avoid the problematic evolution of gaseous hydrogen cyanide, the Schiff base reduction by sodium cyanoborohydride, as the second step of the standard reductive amination protocol, was omitted. Glucose was used as a model...
Glycosylation is one of the most significant and abundant post-translational modifications in cells. Glycomic and glycoproteomic analyses involve the characterization of oligosaccharides (glycans) conjugated to proteins. Glycomic and glycoproteomic analysis is highly challenging because of the large diversity of structures, low abundance, site-spec...
The aim of this study was to improve rivaroxaban water-solubility by cocrystal preparation and to understand this process. The screening with water-soluble coformers was performed via both mechanochemical and solution-mediated techniques. Two cocrystals of rivaroxaban with malonic acid and oxalic acid were prepared, and the structure of the cocryst...
A method for purity control of newly synthesized lactic acid‐based liquid crystals has been developed. The electrokinetic chromatography proved to be suitable for the separation of these electroneutral substances from their impurities. The separations were performed in an acidic acetonitrile‐based background electrolyte with a pseudostationary phas...
One of the major concerns for all in vivo experiments is intra- and inter-subject variability, which can be a great source of inaccuracy. The aim of this study is, therefore, to estimate the ability of parallel vs. cross-over design studies in order to describe the relative pharmacokinetic performance of the studied drug formulations. We analyzed t...
Purpose:
Statin therapy should be considered in children with familial hypercholesterolemia and sustained high LDL-C levels. There are no data on rosuvastatin exposure in patients <6 years and efficacy/safety can only be derived from case reports. Our aim was to examine developmental changes in pharmacokinetics of rosuvastatin in rats in vivo as a...
Increased plasma total cysteine (tCys) has been associated with obesity and metabolic syndrome in human and some animal studies but the underlying mechanisms remain unclear. In this study, we aimed at evaluating the effects of high cysteine diet administered to SHR-CRP transgenic rats, a model of metabolic syndrome and inflammation. SHR-CRP rats we...
Accurate knowledge of the electroosmotic flow mobility is crucial for the determination of effective electrophoretic mobilities in capillary electrophoresis. The addition of a neutral marker to the sample is a common method for electroosmotic flow mobility measurement. Nevertheless, the neutral marker can also exhibit electrophoretic mobility due t...
Background and purpose:
Lymphatic transport of drugs after oral administration is an important mechanism for absorption of highly lipophilic compounds. Direct measurement in lymph duct cannulated animals is the gold standard method, but non-invasive cycloheximide chylomicron flow blocking method has gained popularity recently. However, concerns ab...
This paper highlights the potential of electrochemical flow cells for oxidative-stress testing of active pharmaceutical ingredients using canagliflozin as a model substance. Based on design of experiments, we developed our method through a reduced combinatorial design, optimizing the following independent variables: cell size, electrolyte flow rate...
UV‐absorbing neutral substances are commonly used as markers of mean electroosmotic flow in capillary electrophoresis for their zero electrophoretic mobility in an electric field. However, some of these markers can interact with background electrolyte components and migrate at a different velocity than the electroosmotic flow. Thus, we tested eleve...
Electrochemical conversion of fesoterodine to one of its oxidation products was evaluated with the application of the wall-jet flow cell. A traditional, “static” mode of electrolysis was compared with the “dynamic” mode of cell performance. For statistical assessment of the data, experiments were planned and performed with the application of design...
Abiraterone acetate has limited bioavailability in the fasted state and exhibits a strong positive food effect. We present a novel formulation concept based on the so-called oil marbles (OMs) and show by in vitro and in vivo experiments that the food effect can be suppressed. OMs are spherical particles with a core-shell structure, formed by coatin...
Pythium oligandrum is a unique biological control agent. This soil oomycete not only acts as a mycoparasite, but also interacts with plant roots and stimulates plant defense response via specific elicitors. In addition, P. oligandrum can synthetize auxin precursors and stimulate plant growth. We analyzed the secretomes and biochemical properties of...
Dandelion-flavored syrup, also known as “dandelion honey”, is prepared and used as a substitute for bee honey. One of the major differences between dandelion syrup and bee honey seems to be the carbohydrate composition, as bee honey consists mainly of glucose and fructose while pure sucrose is used for the preparation of dandelion syrup. In this st...
Del Nido cardioplegia solution (dNCS) is frequently used in cardiac surgery. As dNCS is often in-house prepared by hospital pharmacies, an appropriate preparation and storage conditions need to be found and validated. In this study, an 8-week (i.e., 56 days) stability test was performed to monitor the effect of several variables on the stability of...
The composition of a sample solvent has a crucial impact on separations in hydrophilic interaction liquid chromatography (HILIC). In this short communication, we studied the effect of an organic modifier in the sample solvent on the solubility of different tryptic glycopeptides of hemopexin and haptoglobin proteins. The results showed that the solu...
Abiraterone acetate is a potent drug used for the treatment of metastatic castration resistant prostate cancer. However, currently marketed product containing crystalline abiraterone acetate exhibits strong positive food effect which results in strict dosing regimen. In the present work, a rational approach towards design of novel abiraterone aceta...
Interactions between heparin and tetraarginine in an acidic background electrolyte were investigated in capillary electrophoresis. The results showed that tetraarginine and heparin form a stable complex that migrates towards the anode immediately after coming into contact. When a zone of tetraarginine at a mg/mL concentration level passes through a...
The post-mortem toxicological findings may be misinterpreted, if the drug undergoes substantial post-mortem redistribution. As alprazolam is one of the most frequently evaluated drug for legal/forensic reasons in drug-related fatalities, we studied possible changes in alprazolam distribution after death in a rat model. Rats were sacrificed 30 minut...
Fermentation of undigested carbohydrates and amino acids in large intestine leads to production of short-chain fatty acids (SCFA). An increasing attention has been recently drawn to investigating the effect of the presence of SCFA in mammalian large intestine on the colon health. Thus, clinical practice requires analytical methods capable of fast,...
The oligomeric state of the storage form of human insulin in pancreas, which may be affected by several endogenous components of beta cells storage granules such as arginine, is not known. Here, the effect of arginine on insulin oligomerisation is investigated independently by protein crystallography, molecular dynamics simulations and capillary el...
The oligomeric state of the storage form of human insulin in the pancreas, which may be affected by several endogenous components of β-cell storage granules such as arginine, is not known. Here, the effect of arginine on insulin oligomerization is investigated independently by protein crystallography, molecular dynamics simulations, and capillary e...
Organophosphates belong to a family of acetylcholinesterase inhibiting neurotoxins. The toxicity of the parent compound, e.g., chlorpyrifos-methyl is usually tested. However, the toxicity of its transformation products and the transformation process itself are often overlooked. The chlorpyrifos-methyl oxon degradation reaction was monitored using t...
As the demand for medical cannabis preparations increases, so does the use of the common organic solvents that are used in the extraction and quantification of phytocannabinoids. Since common organic solvents are typically hazardous to the environment and to human health, it is vital to identify safer, greener, and more efficient alternatives. The...
Pancreatic α-amylase plays an important role in dietary starch hydrolysis in the small intestine and participates in enhanced glucose concentration after meals. It seems to be a problem for diabetic patients, who suffer from longer postprandial hyperglycemia after meal consumption than healthy people. There are commercially available drugs that inh...
Thanks to its high conductivity when acid doped, polyaniline is known as a synthetic metal and is used in a wide range of applications, such as supercapacitors, biosensors, electrochromic devices or solar and fuel cells. Emeraldine is the partly oxidized, stable form of polyaniline, consisting of alternating diaminobenzenoid and iminoquinoid segmen...
In the present study, we characterize the binding of divalent cations to insulin in aqueous salt solutions by means of capillary electrophoresis and molecular dynamics simulations. The results show a strong pH dependence. At low pH, at which all the carboxylate groups are protonated and the protein has an overall positive charge, all the cations ex...
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The oligomeric state of the storage form of human insulin in pancreas, which may be affected by several endogenous components of beta-cells storage granules such as arginine, is not known. Here, the effect of arginine on insulin oligomerisation is investigated independently by protein crystallography, molecular dynamics simulations and capil...
This project was supported by Charles University (UNCE 204025/2012).
Monosubstituted derivatives of γ-cyclodextrin (γ-CD) are suitable building blocks for supramolecular polymers, and can also serve as precursors for the synthesis of other regioselectively monosubstituted γ-CD derivatives. We prepared a set of monosubstituted 2I-O-, 3I-O-, and 6I-O-(3-(naphthalen-2-yl)prop-2-en-1-yl) derivatives of γ-CD using two di...
Experimental part and data for compounds 2a, 2b, and 2c: copies of NMR spectra and DLS.
Separation potential of a stationary phase based on polyaniline-coated silica gel porous spherical particles was investigated in different chromatographic modes of capillary liquid chromatography. l-Tryptophan and three of its structural derivatives with modified amino or carboxylic functionality were used to investigate the retention factor curves...
High anion gap metabolic acidosis frequently complicates acute paracetamol overdose and is generally attributed to lactic acidosis or compromised hepatic function. However, metabolic acidosis can also be caused by organic acid 5-oxoproline (pyroglutamic acid). Paracetamol’s toxic intermediate, N-acetyl-p-benzoquinoneimine irreversibly binds to glut...
The increase in the number of bacterial strains resistant to known antibiotics is alarming. In this study we report the synthesis of novel compounds termed Lipophosphonoxins II (LPPO II). We show that LPPO II display excellent activities against Gram positive and -negative bacteria, including pathogens and multiresistant strains. We describe their...
In this study, we optimized a method for the determination of free amino acids in Nicotiana tabacum leaves. Capillary electrophoresis with contactless conductivity detector was used for the separation of 20 proteinogenic amino acids in acidic background electrolyte. Subsequently, the conditions of extraction with HCl were optimized for the highest...
A fast and inexpensive method for simultaneous determination of total protamine and insulin has been developed using capillary electrophoresis in the short-end injection setup with a bare-fused silica capillary. Optimized background electrolyte consists of 45 mM aqueous solution of phosphoric acid, pH 1.85. Separation is finished within 1 min; tota...
A polyaniline coating was used to modify the surface of bare silica gel and octadecyl silica stationary phases to characterize the properties of altered materials. It was assumed that the mixed-mode retention was established on the basis of the polyaniline chemical structure and its combination with the original sorbents. Polyaniline was deposited...
Polyaniline (PANI), a highly stable polymer of interesting chemistry, was used to modify the surface of the bare silica gel (SiO2, Hypersil®) and octadecyl silica (C18, Nucleosil® C18) spherical particles (5 μm in diameter). Polyaniline-coated sorbents were investigated by optical and scanning electron microscopy (SEM) and specific surface area ana...
This work deals with the development and optimization of the sample pretreatment and consequent electrophoretic analysis of two modern plating baths containing chromium(III) and either citric acid or oxalic acid. Some model mixtures containing known amounts of components of industrial baths have been prepared to simulate simplified bath matrices. P...
Polyanilinine (PANI) is an easily synthesized high stable semiconducting polymer forming a bulk precipitate and a thin film on the surface of the material in direct contact. It can be polymerized chemically or electrochemically, under acidic conditions creating structure of emeraldine salt. In the recent years, some materials such as glass, carbon,...
A low-cost, thin, graphitized carbon electrode with electrodeposited platinum and polyaniline has been characterized for electrochemical oxidation of aliphatic alcohols in alkaline medium and for possible further incorporation of atomic metals and alloys. Our previously developed atomic metal polyaniline composites used solid platinum as the electr...
The kinetic properties of β-N-acetylhexosaminidase purified from tobacco (Nicotiana tabacum L.) leaves have been investigated. In addition to chromogenic pNP derivates, N,N´-diacetylchitobiose and N,N´,N´´-triacetylchitotriose were also used as substrates of β-N-acetylhexosaminidase. The highest reaction rate and the affinity for the substrate were...
What & Why: Development of industrial technologies using nontoxic, environmentally-friendly substances is a hot topic nowadays. Some of small carboxylic acids are important components of various surface finishing baths. Their usage as complexing and pH-stabilizing agents significantly improves the effectiveness of the technological process. Final c...
This work was concerned with developing an electrophoretic method for rapid determination of nitrites and nitrates in drinking water. The background electrolyte was Tris-HCl buffer with an addition of cetyltrimethylammonium chloride to reverse the electro-osmotic flow. Online preconcentration of samples using the field-amplified sample stacking met...
Small neutral organic compounds have traditionally the role of electroosmotic flow markers in electrophoresis, as they are expected to have zero electrophoretic mobility in external electric fields. The background electrolyte contains, however, ions which have unequal affinities to the neutral molecules, which in turn results in their mobilization....
Enzyme assays of β-N-acetylhexosaminidase from Aspergillus oryzae using capillary electrophoresis in the offline and online setup have been developed. The pH value and concentration of the borate-based background electrolyte were optimized in order to achieve baseline separation of N,N′,N″-triacetylchitotriose, N,N′-diacetylchitobiose, and N-acetyl...
Charge reversal as an extreme case of charge compensation is directly observed by capillary electrophoresis for a negatively charged peptide in aqueous solutions of trivalent cations. Atomistic and coarse-grained simulations provide molecular interpretation of this effect showing that it is largely of electrostatic origin with a minor contribution...
We investigated the effect of the background electrolyte (BGE) anions on the electrophoretic mobilities of the cationic amino acids arginine and lysine and the polycationic peptides tetraarginine, tetralysine, nonaarginine, and nonalysine. BGEs composed of sodium chloride, sodium propane-1,3-disulfonate, and sodium sulfate were used. For the amino...
Miniaturization continues to be one of the leading trends in analytical chemistry and one that brings advantages that can be particularly beneficial in biochemical research. Use of a miniaturized scale enables efficient analysis in a short time and requires very small amounts of samples, solvents, and reagents. This can result in a remarkable decre...
Using capillary electrophoresis and molecular dynamics simulations, we directly demonstrate that guanidinium cations exhibit an affinity for the positively charged side chains of arginine-containing peptides in aqueous solutions, while no such effect is observed for sodium cations and/or lysine. Such a counterintuitive pairing between these two pos...
A very simple and readily performed method is described for the preparation of poly(styrene-divinylbenzene-methacrylic acid) monolithic columns for capillary liquid chromatography. The effect of the methacrylic acid content on the morphological and chromatographic properties has been investigated. Methacrylic acid is shown to be essential for isocr...
Domains rich in cationic amino acids are ubiquitous in peptides with the ability to cross cell membranes, which is likely related to the binding of such polypeptides to anionic groups on the membrane surface. To shed more light on these interactions, we investigated specific interactions between basic amino acids and oligopeptides thereof and anion...
Polymeric macromolecules of well-designed structures and specific properties open promising directions in the capillary entangled polymer electrophoresis. Pluronic F-127, as a thermoassociating polymer, possesses some unique properties that can be utilized in capillary entangled polymer electrophoresis of amino acids, peptides and proteins. In this...
In proteomics, proteins can be identified by enzymatic cleavage of the target protein using an enzyme of the known specificity (primarily trypsin), sequencing the obtained specific peptides by MS and comparing the amino acid sequence of the peptides with a protein database. The sophisticated approach described above was used in this study to determ...
RP-HPLC and non-aqueous CZE methods were evaluated for qualitative and quantitative analysis of esterified macrocyclic compounds of the DOTA family (DOTA=1,4,7,10-tetraazacyclododecan-1,4,7,10-tetraacetic acid). This group of compounds represents important reaction intermediates in synthesis of magnetic resonance contrast agents. Calibration curves...
The separation of relatively small, fast-migrating anions by CE is not possible under standard conditions with cathodic EOF of relatively high velocity. Therefore, separation approaches for these analytes usually include suppression or reversal of the EOF using various cationic additives to the BGE or covalent coating of the capillary walls. In thi...
Capillary gel electrophoresis (CGE) is a promising proteomic technique. It involves many parameters which can be manipulated to optimize the CGE method for particular application, first of all the type of separation gel. Physical gels possess certain advantages over the chemical ones. Not being covalently crosslinked, physical gels exhibit lower vi...
Projects
Projects (2)
Project focuses on datafillin NSD database. Moreover, monitoring in the terrain, biological materials and identification of new synthetic drugs precursor. The addictive potential and mechanism of action (interaction with receptors and transporters, influence on brain neurobiological substrates) of the chosen representatives of NSD from different chemical groups will be evaluated. Information about NSD will be submitted for risk assessment in EMCDDA.