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Dive into the research topics where Zuzana Vitková is active.

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Featured researches published by Zuzana Vitková.


Tenside Surfactants Detergents | 2012

Study of Micelle Properties and Thermodynamics of Micellization of the Benzethonium Chloride

Jarmila Oremusová; Zuzana Vitková; Anton Vitko

Abstract The self-association of benzethonium chloride (BZCl) in aqueous solution has been analyzed as a function of temperature. The critical micelle concentration (CMC.), the degree of counterion binding (β) and thermodynamic parameters of micellization (molar Gibbs energy, enthalpy and entropy of micellization) were determined using six experimental methods (conductometry, potentiometry, UV spectrophotometry, spectrofluorimetry, NMR and densitometry) within the temperature range 20–50°C. All methods used gave very similar values for CMC. Changes in the thermodynamic parameters on micellization were determined by applying a mass action model.


Tenside Surfactants Detergents | 2011

Influence of Surfactants on Release of Chlorhexidine from Hydrogels

Zuzana Vitková; Jarmilla Oremusová; Anton Vitko; Ž. Bezáková

Abstract In Slovakia chlorhexidine is available in dosage forms of solutions, creams and pastes but not in the form of hydrogels, though they are modern drug forms with many positive properties. Therefore, in this article possibilities of its formulation into hydrogels are studied. In particular, two research aims were followed. The first consisted in study of an influence of surface active agents on the release of chlorhexidine dihydrochloride from chitosan hydrogels and the second one was to design a formulation of hydrogels for local delivery of chlorhexidine to the oral cavity. To this end, surfactants from the group of alkyltrimethylammonium bromides with the length of alkyl chain C6–C18 which occupy a dominant position in the indication group of antiseptics and disinficients were analyzed with intention to use them in preparation of hydrogels. Hydrogels were prepared with 2.5% (w/w) gel-forming agent chitosan. Both the active agent and surfactants were used in 0.1% (w/w) concentration. It is shown that the surface active agents with short alkyl chain are suitable for development of chlorhexidine dihydrochloride hydrogels with controlled release.


Tenside Surfactants Detergents | 2015

Model Based Approach to Study of Release Kinetics of the Drug Chlorhexidine from Hydrogels

Zuzana Vitková; Jarmilla Oremusová; Petra Herdová; Anton Vitko; Olga Ivanková

Abstract Knowledge of the release kinetics together with its (mathematical) model is inevitable for prediction of properties and optimization of dosage forms. The ability to optimize the release kinetics is a key factor in the endeavour of increasing pharmaceutical availability. The optimization may be done by a suitable choice of the dosage form or by clever distribution of the drug in the auxiliary substances or even by using an automatically working drug delivery device. This paper describes a model-based analysis and preparation of hydrogels. The following composition was used in the experiment: Chitosan – the gel creating basis; polymer, chlorhexidine – the drug; dodecyltrimethylammonium bromide – the auxiliary substance and surfactant. The release kinetics were studied at three temperatures and were evaluated by using several models (zero order, pseudo-first order, first order, Higuchi, Hixon Crowell, Weibul distribution and Korsmeyer-Peppas). It was found that the best fitting model of the drug release was the Higuchi model. So as to predict character of the release process (exothermic and spontaneous), the activation energy, activation enthalpy, entropy and Gibbs free energy were evaluated.


Drug Development and Industrial Pharmacy | 2015

Formulation of sage essential oil (Salvia officinalis, L.) monoterpenes into chitosan hydrogels and permeation study with GC-MS analysis

Alexandra Kodadová; Zuzana Vitková; Petra Herdová; Anton Ťažký; Jarmila Oremusová; Daniel Grančai; Peter Mikuš

Abstract This study deals with the formulation of natural drugs into hydrogels. For the first time, compounds from the sage essential oil were formulated into chitosan hydrogels. A sample preparation procedure for hydrophobic volatile analytes present in a hydrophilic water matrix along with an analytical method based on the gas chromatography coupled with the mass spectrometry (GC-MS) was developed and applied for the evaluation of the identity and quantity of essential oil components in the hydrogels and saline samples. The experimental results revealed that the chitosan hydrogels are suitable for the formulation of sage essential oil. The monoterpene release can be effectively controlled by both chitosan and caffeine concentration in the hydrogels. Permeation experiment, based on a hydrogel with the optimized composition [3.5% (w/w) sage essential oil, 2.0% (w/w) caffeine, 2.5% (w/w) chitosan and 0.1% (w/w) Tween-80] in donor compartment, saline solution in acceptor compartment, and semi-permeable cellophane membrane, demonstrated the useful permeation selectivity. Here, (according to lipophilicity) an enhanced permeation of the bicyclic monoterpenes with antiflogistic and antiseptic properties (eucalyptol, camphor and borneol) and, at the same time, suppressed permeation of toxic thujone (not exceeding its permitted applicable concentration) was observed. These properties highlight the pharmaceutical importance of the developed chitosan hydrogel formulating sage essential oil in the dermal applications.


Tenside Surfactants Detergents | 2014

Influence of Alcohols on Micellar and Release Balances of Cationic Surfactant – Carbethopendecinium Bromide (Septonex)

Jarmila Oremusová; Zuzana Vitková; Petra Herdová

Abstract An objective of this work is analysis of influence of selected alcohols from the group of enhancers (ethanol, propan-1-ol, propan-2-ol) and humectants (ethane-1,2-diol, propane-1,2-diol and propane-1,2,3-triol) in the hydrogels containing carbethopendecinium bromide on their associative (critical micelle concentration and thermodynamic parameters) and release properties (pH, percentage of drug release and the release rate constant). The studied hydrogels contained constant amounts of the gel-creating basis (polymer chitosan – 2.5% w/w), drug carbethopendecinium bromide (Septonex) – 1.0% w/w and additive of alcohol in 5 and 10% w/w concentrations. Associative parameter – critical micelle concentration (CMC) was evaluated by conductometric measurements. The CMC significantly increased in the environment of alcohols in comparison with water solutions as many as 50 times, while concentration of alcohols ranged within W = 0–100% mass fractions. Micellization in the both environments was spontaneous (ΔGm < 0), and from the energetic point of view it was exothermic (ΔHm < 0). The additive of alcohols in hydrogels supported the drug relase from hydrogels. As the concentration of alcohols increased the mass percentage of the drug released from gel increased as well.


Zeitschrift für Naturforschung C | 2017

Simultaneous formulation of terbinafine and salvia monoterpenes into chitosan hydrogel with testing biological activity of corresponding dialysates against C. albicans yeast

Alexandra Kodadová; Zuzana Vitková; Jarmila Oremusová; Petra Herdová; Anton Ťažký; Peter Mikuš

Abstract This work was aimed at a progressive formulation of drugs into chitosan hydrogels. It was taken into consideration that a therapeutic effect of the drugs could be enhanced by a combination of natural compounds with chemical (synthetic) drugs. In this work, sage essential oil (SEO) bicyclic monoterpenes with antiflogistic, antiseptic, and antimycotic properties were combined with terbinafine (TB) having a strong antimycotic activity. Detail optimization of the hydrogel-drugs composition (SEO monoterpenes, TB, chitosan, and polysorbate 80 concentrations), based on permeation experiment and UV absorption/GC-MS analysis of permeated species (eucalyptol, camphor, borneol, thujone, TB) in dialysates, was made. Concerning the active drugs formulation, an optimum concentration of TB was set at the level providing maximum release of the SEO monoterpenes. In vitro activity of the dialysates from the optimized hydrogel was tested against Candida albicans showing that a minimum inhibition concentration was significantly exceeded. The experimental results revealed that the chitosan hydrogel was suitable for the simultaneous formulation of the natural drugs (SEO) with chemical drug (TB) resulting in the preparation with acceptable stability, required gel properties, and significant biological activity. Such preparation should be effective in an antimycotic dermal use.


Molecules | 2017

Association, Distribution, Liberation, and Rheological Balances of Alkyldimethylbenzylammonium Chlorides (C12–C16)

Zuzana Vitková; Jarmila Oremusová; Petra Herdová; Oľga Ivánková; Anton Vitko

It is known that cationic surfactants have an antimicrobial effect and act as enhancers. This paper studies three cationic surfactants from the group of alkyldimethylbenzylammonium chlorides (dodecyl-, tetradecyl-, and hexadecyl). Interest is focused on the association of the surfactants with respect to temperature, partition balances and their influence on drug release, rheological properties, and the pH of hydrogels. The critical micelle concentrations (CMC) of the surfactants were estimated from dependencies of conductivity, density, spectrofluorimetry, and UV–VIS spectrophotometry on molarity in the temperature range of 25–50 °C. It was found that the temperature dependence of a CMC is U-shaped, with its minimum at 30 °C, and the CMC value decreases as the length of the chain increases. The pseudo-phase separation model was used for the calculation of various thermodynamic parameters, such as the Gibbs free energies (spontaneous process), enthalpies (exothermic process), and entropies of the micelles’ formation, CMCs, and the degree of counterion binding. All thermodynamic parameters, as functions of the temperature, were estimated. It was found that partition coefficients increase as the length of the alkyl chain and the pH = (5.0–7.0) increase. The influences of surfactants, below and above the CMC, on drug (chlorhexidine dihydrochloride) release from hydrogels, rheological properties, and pH at 30 °C were studied. Also, the amounts of the released drug increase as the alkyl chains of the surfactants prolongate. The amounts of the released drug with the surfactant below the CMC are greater than that above the CMC. All hydrogels (regardless of the length of the alkyl chain) exhibit a non-Newtonian pseudo-plastic flow. The results obtained will be used in the formulation of the drug and surfactants into dosage forms.


Tenside Surfactants Detergents | 2014

Study of Surfactant (Benzyldimethylhexadecylammonium Chloride) Effect on Selected Properties of Hydrogels

Petra Herdová; Zuzana Vitková; Jarmila Oremusová

Abstract This paper aims to provide analysis of the influences of concentration changes of the surfactant – benzyldimethylhexadecylammonium chloride in hydrogels on their liberation, rheological, association and solubility properties. The hydrogels contained constant amounts of the gel-creating basis (polymer chitosan – 2.5 % w/w), the drug (chlorhexidine dihydrochloride – 0.1 % w/w) and the surfactant, which was used as an enhancer (0.005 – 0.05 % w/w). The highest value of the released drug corresponded to the highest surfactant concentration in the hydrogel. Critical micelle concentration and thermodynamic parameters, molar Gibbs energy, enthalpy and entropy of micellization were calculated. A linear increase of the surfactant amounts in hydrogels caused a non-linear increase of the cloud point. The appearance of the surfactants associates in hydrogels influenced both their liberation and rheological properties.


Chemical Papers | 2009

Adsorption and release of terbinafine hydrochloride: Effects of adsorbents, additives, pH, and temperature

Zuzana Vitková; Jarmila Oremusová; Oľga Greksáková

The paper describes results obtained within the study of factors affecting the process of an antifungal drug — terbinafine hydrochloride adsorption on two different adsorbents — charcoal and silicagel. The effects of the adsorbent area, pH value, temperature and additives (polymers — methyl cellulose and hydroxypropyl cellulose) were analyzed and their impact on the adsorption of terbinafine was derived. The increase of pH and temperature, and the presence of additives decreased the amount of terbinafine adsorbed on the adsorbents. Terbinafine is currently applied both perorally and topically. Hydrogels, i.e. compositions of a drug, additives and water, are, due to their advantageous properties, preferred topical dosage forms. Mass fraction of additives of 1 % to 4 % were studied from the view point of drug release. This study shows that both the sort and the concentration of polymers influence the drug release from hydrogels significantly.


Acta Veterinaria Brno | 2012

Formulation and release of alaptide from cellulose-based hydrogels

Zbyněk Sklenář; Zuzana Vitková; Petra Herdová; Kateřina Horáčková; Veronika Šimunková

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Jarmila Oremusová

Comenius University in Bratislava

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Petra Herdová

Comenius University in Bratislava

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Peter Mikuš

Comenius University in Bratislava

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Daniel Grančai

Comenius University in Bratislava

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Oľga Greksáková

Comenius University in Bratislava

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Veronika Šimunková

Comenius University in Bratislava

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Kateřina Horáčková

University of Veterinary and Pharmaceutical Sciences Brno

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Zbyněk Sklenář

Charles University in Prague

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