Publications by authors named "Kateřina Dědková"

11 Publications

  • Page 1 of 1

Improvement of Glibenclamide Water Solubility by Nanoparticle Preparation.

J Nanosci Nanotechnol 2019 05;19(5):3031-3034

Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Comenius University, Odbojarov 10, 832 32 Bratislava, Slovakia.

Glibenclamide, a drug used for the treatment of type 2 diabetes, belongs to Class II of Biopharmaceutical Classification System. It is a highly permeable, but poorly water-soluble drug. Nanoparticles of glibenclamide were prepared by an emulsion solvent evaporation method using dichloromethane as a solvent of glibenclamide and 3% (w/w) aqueous solution of carboxymethyl dextran sodium salt as a stabilizer, which was found as optimal. A solubility test comparing the water solubility of glibenclamide bulk and nanoparticles confirmed the improved (2-fold higher) solubility of glibenclamide nanoparticles (0.045 g/ml) compared with bulk (0.024 g/ml).
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http://dx.doi.org/10.1166/jnn.2019.15876DOI Listing
May 2019

Synthesis and Characterization of Erbium Oxide Nanocrystallites.

J Nanosci Nanotechnol 2019 05;19(5):2934-2937

Nanotechnology Centre, VŠB - Technical University of Ostrava, 17. listopadu 15, 708 33 Ostrava - Poruba, Czech Republic.

The present article describes a method of the preparation of erbium oxide nanocrystallites (nano Er₂O₃) via thermal decomposition of a transient complex formed from Er(NO₃)₃·5H₂O and glycine. Decomposition of the complex occurred at about of (250±10) °C. Ultra-fine light pink powder of erbium oxide nanocrystallites was obtained via this method. The resulting nanocrystallites were characterized using X-ray powder diffraction analysis, which showed the nanocrystallites having the crystallite size equal to 10 nm. Morphology of the nanocrystallites was examined by scanning and transmission electron microscopy. Electron diffraction observed in transmission electron microscopy corresponds to the results obtained from X-ray diffraction analysis. The elemental composition of the product was confirmed by EDS analysis.
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http://dx.doi.org/10.1166/jnn.2019.15857DOI Listing
May 2019

Settled iron-based road dust and its characteristics and possible association with detection in human tissues.

Environ Sci Pollut Res Int 2019 Jan 30;26(3):2950-2959. Epub 2018 Nov 30.

Center for Advanced Innovation Technologies, VŠB-Technical University of Ostrava,, 70800, Ostrava, Czech Republic.

Settled road dust was examined to detect the presence of non-airborne submicron and nano-sized iron-based particles and to characterize these particles. Samples were collected from a road surface near a busy road junction in the city of Ostrava, Czech Republic, once a month from March to October. The eight collected samples were subjected to a combination of experimental techniques including elemental analysis, Raman microspectroscopy, scanning electron microscopy (SEM) analysis, and magnetometry. The data thereby obtained confirmed the presence of non-agglomerated spherical nano-sized iron-based particles, with average sizes ranging from 2 down to 490 nm. There are several sources in road traffic which generate road dust particles, including exhaust and non-exhaust processes. Some of them (e.g., brake wear) produce iron as the dominant metallic element. Raman microspectroscopy revealed forms of iron (mainly as oxides, FeO, and mixtures of FeO and FeO). Moreover, FeO was also detected in samples of human tissues from the upper and lower respiratory tract. In view of the fact that no agglomeration of those particles was found by SEM, it is supposed that these particles may be easily resuspended and represent a risk to human health due to inhalation exposure, as proved by the detection of particles with similar morphology and phase composition in human tissues.
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http://dx.doi.org/10.1007/s11356-018-3841-xDOI Listing
January 2019

Preparation of Hydrochlorothiazide Nanoparticles for Solubility Enhancement.

Molecules 2016 Aug 2;21(8). Epub 2016 Aug 2.

Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Comenius University, Odbojarov 10, 832 32 Bratislava, Slovakia.

Nanoparticles can be considered as a useful tool for improving properties of poorly soluble active ingredients. Hydrochlorothiazide (Class IV of the Biopharmaceutical Classification System) was chosen as a model compound. Antisolvent precipitation-solvent evaporation and emulsion solvent evaporation methods were used for preparation of 18 samples containing hydrochlorothiazide nanoparticles. Water solutions of surfactants sodium dodecyl sulfate, Tween 80 and carboxymethyl dextran were used in mass concentrations of 1%, 3% and 5%. Acetone and dichloromethane were used as solvents of the model compound. The particle size of the prepared samples was measured by dynamic light scattering. The selected sample of hydrochlorothiazide nanoparticles stabilized with carboxymethyl dextran sodium salt with particle size 2.6 nm was characterized additionally by Fourier transform mid-infrared spectroscopy and scanning electron microscopy. It was found that the solubility of this sample was 6.5-fold higher than that of bulk hydrochlorothiazide.
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http://dx.doi.org/10.3390/molecules21081005DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6274297PMC
August 2016

ZnO/graphite composites and its antibacterial activity at different conditions.

J Photochem Photobiol B 2015 Oct 22;151:256-63. Epub 2015 Aug 22.

Nanotechnology Centre, VŠB-Technical University of Ostrava, 17. listopadu 15/2172, 708 33 Ostrava-Poruba, Czech Republic; Regional Materials Science and Technology Centre, VŠB-Technical University of Ostrava, 17. listopadu 15/2172, 708 33 Ostrava-Poruba, Czech Republic.

The paper reports laboratory preparation, characterization and in vitro evaluation of antibacterial activity of ZnO/graphite nanocomposites. Zinc chloride and sodium carbonate served as precursors for synthesis of zinc oxide, while micromilled and natural graphite were used as the matrix for ZnO nanoparticles anchoring. During the reaction of ZnCl2 with saturated aqueous solution of Na2CO3a new compound is created. During the calcination at the temperature of 500 °C this new precursors decomposes and ZnO nanoparticles are formed. Composites ZnO/graphite with 50 wt.% of ZnO particles were prepared. X-ray powder diffraction and Raman microspectroscopy served as phase-analytical methods. Scanning electron microscopy technique was used for morphology characterization of the prepared samples and EDS mapping for visualization of elemental distribution. A developed modification of the standard microdilution test was used for in vitro evaluation of daylight induced antibacterial activity and antibacterial activity at dark conditions. Common human pathogens served as microorganism for antibacterial assay. Antibacterial activity of ZnO/graphite composites could be based on photocatalytic reaction; however there is a role of Zn(2+) ions on the resulting antibacterial activity which proved the experiments in dark condition. There is synergistic effect between Zn(2+) caused and reactive oxygen species caused antibacterial activity.
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http://dx.doi.org/10.1016/j.jphotobiol.2015.08.017DOI Listing
October 2015

Micro- and Nanosized Particles in Nasal Mucosa: A Pilot Study.

Biomed Res Int 2015 1;2015:505986. Epub 2015 Jun 1.

Department of Otorhinolaryngology, Head and Neck Surgery, University Hospital Ostrava, 17. Listopadu 1790, 708 52 Ostrava, Czech Republic ; Faculty of Medicine, University of Ostrava, Syllabova 19, 703 00 Ostrava, Czech Republic.

Objective: The aim of this prospective study is to evaluate presence and quantity of micro- and nanosized particles (NPs) and interindividual differences in their distribution and composition in nasal mucosa.

Methods: Six samples of nasal mucosa obtained by mucotomy from patients with chronic hypertrophic rhinosinusitis were examined. Samples divided into 4 parts according to the distance from the nostrils were analyzed by scanning electron microscopy and Raman microspectroscopy to detect solid particles and characterize their morphology and composition. A novel method of quantification of the particles was designed and used to evaluate interindividual differences in distribution of the particles. The findings were compared with patients' employment history.

Results: In all the samples, NPs of different elemental composition were found (iron, barium, copper, titanium, etc.), predominantly in the parts most distant from nostrils, in various depths from the surface of the mucosa and interindividual differences in their quantity and composition were found, possibly in relation to professional exposition.

Conclusions: This study has proven the possibility of quantification of distribution of micro- and nanosized particles in tissue samples and that the NPs may deposit in deeper layers of mucosa and their elemental composition may be related to professional exposition to the sources of NPs.
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http://dx.doi.org/10.1155/2015/505986DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4466340PMC
March 2016

Nanostructured composite material graphite/TiO2 and its antibacterial activity under visible light irradiation.

J Photochem Photobiol B 2015 Aug 19;149:265-71. Epub 2015 Jun 19.

Nanotechnology Centre, VŠB - Technical University of Ostrava, 17. listopadu 15, 708 33 Ostrava-Poruba, Czech Republic; Regional Materials Science and Technology Centre, VŠB - Technical University of Ostrava, 17. listopadu 15, 708 33 Ostrava-Poruba, Czech Republic.

The paper addresses laboratory preparation, characterization and in vitro evaluation of antibacterial activity of graphite/TiO2 nanocomposites. Composites graphite/TiO2 with various ratio of TiO2 nanoparticles (30wt.%, and 50wt.%) to graphite were prepared using a thermal hydrolysis of titanylsulfate in the presence of graphite particles, and subsequently dried at 80°C. X-ray powder diffraction, transmission electron microscopy and Raman microspectroscopy served as phase-analytical methods distinguishing anatase and rutile phases in the prepared composites. Scanning and transmission electron microscopy techniques were used for characterization of morphology of the prepared samples. A developed modification of the standard microdilution test was used for in vitro evaluation of daylight induced antibacterial activity, using four common human pathogenic bacterial strains (Staphylococcus aureus, Escherichia coli, Enterococcus faecalis and Pseudomonas aeruginosa). Antibacterial activity of the graphite/TiO2 nanocomposites could be based mainly on photocatalytic reaction with subsequent potential interaction of reactive oxygen species with bacterial cells. During the antibacterial activity experiments, the graphite/TiO2 nanocomposites exhibited antibacterial activity, where differences in the onset of activity and activity against bacterial strains were observed. The highest antibacterial activity evaluated as minimum inhibitory concentration was observed against P. aeruginosa after 180min of irradiation.
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http://dx.doi.org/10.1016/j.jphotobiol.2015.06.018DOI Listing
August 2015

Preparation, characterization and antibacterial properties of ZnO/kaoline nanocomposites.

J Photochem Photobiol B 2015 Jul 13;148:113-117. Epub 2015 Apr 13.

Nanotechnology Centre, VŠB - Technical University of Ostrava, 17. listopadu 15, 708 33 Ostrava-Poruba, Czech Republic.

This paper describes laboratory preparation, characterization and antibacterial activity testing of ZnO/kaoline composites. ZnO/kaoline composites with 50 wt.% of ZnO were laboratory prepared, dried at 105 °C and calcined at 500 °C. XRPD analysis revealed that thermal treatment caused the phase transformation of Zn containing precursor into ZnO. Scanning and transmission electron microscopy techniques were used for characterization of morphology of the prepared samples. A standard microdilution test was used for evaluation of antibacterial activity using four common human pathogens (Staphylococcus aureus, Escherichia coli, Enterococcus faecalis and Pseudomonas aeruginosa). Daylight was used for induction photocatalytically based antibacterial activity. Second possible explanation of antibacterial activity of ZnO/kaoline could be the presence of biologically available forms of zinc. During the antibacterial activity assays the ZnO/kaoline composites exhibited antibacterial activity, where differences in an onset of the antibacterial activity and activity against bacterial strains were observed. The highest antibacterial activity was observed against S. aureus, where the lowest value of minimum inhibitory concentration was determined equal to 0.41 mg/ml.
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http://dx.doi.org/10.1016/j.jphotobiol.2015.03.034DOI Listing
July 2015

Preparation of risedronate nanoparticles by solvent evaporation technique.

Molecules 2014 Nov 4;19(11):17848-61. Epub 2014 Nov 4.

Department of Chemical Drugs, Faculty of Pharmacy, University of Veterinary and Pharmaceutical Sciences, Palackeho 1/3, Brno 61242, Czech Republic.

One approach for the enhancement of oral drug bioavailability is the technique of nanoparticle preparation. Risedronate sodium (Biopharmaceutical Classification System Class III) was chosen as a model compound with high water solubility and low intestinal permeability. Eighteen samples of risedronate sodium were prepared by the solvent evaporation technique with sodium dodecyl sulfate, polysorbate, macrogol, sodium carboxymethyl cellulose and sodium carboxymethyl dextran as nanoparticle stabilizers applied in three concentrations. The prepared samples were characterized by dynamic light scattering and scanning electron microscopy. Fourier transform mid-infrared spectroscopy was used for verification of the composition of the samples. The particle size of sixteen samples was less than 200 nm. Polysorbate, sodium carboxymethyl dextran and macrogol were determined as the most favourable excipients; the particle size of the samples of risedronate with these excipients ranged from 2.8 to 10.5 nm.
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http://dx.doi.org/10.3390/molecules191117848DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6271162PMC
November 2014

Iron-based granules in body of bumblebees.

Biometals 2015 Feb 28;28(1):89-99. Epub 2014 Oct 28.

IT4Innovations Centre and Institute of Physics, VSB - Technical University of Ostrava, 17. listopadu 15/2172, 708 33, Ostrava, Czech Republic,

The paper deals with the presence of iron-based granules in body parts of bumblebees. Two groups of bumblebees were collected from their natural habitat, industrial landscape, and from a breeding station. Detection of the magnetic particles was performed by a vibratory magnetometer and their morphology and elemental composition was analysed by scanning electron microscopy with EDX microanalysis. By means of the EDX spectra, wild bumblebees were found to have many magnetic and non-magnetic particles on their body, containing Fe, O, Al, Si, Bi, Mg, K, and Ni, likely having origin in the industrial pollution of the environment. In the case of bred bumblebees the presence of iron-rich granules, which occurred more abundantly in subsurface tissues on the head and wings, was observed. Phase analysis based on X-ray diffraction shows that iron-based granules contain magnetite and wuestite and Mössbauer spectroscopy admits a superparamagnetic form of these minerals. Magnetoreception, i.e. the sensory function of these granules, is discussed within the paper.
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http://dx.doi.org/10.1007/s10534-014-9805-9DOI Listing
February 2015

Antibacterial activity of kaolinite/nanoTiO2 composites in relation to irradiation time.

J Photochem Photobiol B 2014 Jun 18;135:17-22. Epub 2014 Apr 18.

Nanotechnology Centre, VŠB - Technical University of Ostrava, 17. listopadu 15, 708 33 Ostrava, Poruba, Czech Republic.

The paper addresses laboratory preparation and antibacterial activity testing of kaolinite/nanoTiO2 composite in respect of the daylight irradiation time. Kaolinite/nanoTiO2 composites with 20 and 40 wt% of TiO2 were laboratory prepared, dried at 105 °C and calcined at 600 °C. The calcination caused transformation of kaolinite to metakaolinite and origination of the metakaolinite/nanoTiO2 composite. X-ray powder diffraction, Raman and FTIR spectroscopic methods revealed titanium dioxide only in the form of anatase in all evaluated samples (non-calcined and calcined) and also transformation of kaolinite to metakaolinite after the calcination treatment. Scanning electron microscopy was used as a method for characterization of morphology and elemental composition of the studied samples. A standard microdilution test was used to determine the antibacterial activity using four human pathogenic bacterial strains (Staphylococcus aureus, Escherichia coli, Enterococcus faecalis, Pseudomonas aeruginosa). A lamp with a wide spectrum bulb simulating daylight was used for induction of photocatalysis. The antibacterial assays found all the KATI samples to have antibacterial potency with different onset of the activity when calcined samples exhibited antibacterial activity earlier than the non-calcined. Significant difference in antibacterial activity of KATI samples for different bacterial strains was not observed.
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http://dx.doi.org/10.1016/j.jphotobiol.2014.04.004DOI Listing
June 2014