Ales Zadrazil

Ales Zadrazil
University of Chemistry and Technology, Prague | VSCHT · Chemical Robotics Laboratory (LCHR)

PhD

About

27
Publications
3,042
Reads
How we measure 'reads'
A 'read' is counted each time someone views a publication summary (such as the title, abstract, and list of authors), clicks on a figure, or views or downloads the full-text. Learn more
269
Citations
Citations since 2017
15 Research Items
167 Citations
2017201820192020202120222023010203040
2017201820192020202120222023010203040
2017201820192020202120222023010203040
2017201820192020202120222023010203040

Publications

Publications (27)
Article
Encapsulation of active compounds into liquid marbles (LMs) represents an emerging technology with potential applications in several fields including food, cosmetics and pharmaceutics. However, existing methods for the preparation of LMs are either based on manual one-by-one fabrication or on batch processes such as high-shear granulation, which la...
Article
Full-text available
Purpose Fluid-bed coating processes make it possible to manufacture pharmaceutical products with tuneable properties. The choice of polymer type and coating thickness provides control over the drug release characteristics, and multi-layer pellet coatings can combine several active ingredients or achieve tailored drug release profiles. However, the...
Article
Drug depot systems have traditionally relied on the spontaneous dissolution and diffusion of drugs or prodrugs from a reservoir with constant exposure to the surrounding physiological fluids. While this is appropriate for clinical scenarios that require constant plasma concentration of the drug over time, there are also situations where multiple bu...
Article
Dissolution testing is widely used to measure the rate of drug release and predict its in-vivo behavior. The release rate can be controlled by adjusting the particle size distribution (PSD). However, experimental investigation of various particle sizes requires many time-consuming experiments. To reduce the need for them, we propose an optimization...
Article
Lipid bilayers are the basic structural components of all living systems, forming the membranes of cells, sub-cellular organelles, and extracellular vesicles. A class of man-made lipidic vesicles called multilobed magnetic liposomes (MMLs) is reported in this work; these MMLs possess a previously unattained combination of features owing to their un...
Article
Microfluidics allows to accurately control the synthesis of microparticles for specific applications, where size and morphology play an important role. In this work, we introduce microfluidic chip design with dedicated extraction and gelation sections allowing to prepare hydrogel particles in size range of a red blood cell. The influence of the ext...
Article
Amorphisation using mesoporous inorganic carriers represents an emerging formulation strategy for the dissolution rate enhancement of poorly water-soluble Active Pharmaceutical Ingredients (APIs). This approach employs API loading to a porous carrier, which stabilises the amorphous form and prevents recrystallisation due to spatial confinement in t...
Article
Full-text available
Many new therapeutic candidates and active pharmaceutical ingredients (APIs) are poorly soluble in an aqueous environment, resulting in their reduced bioavailability. A promising way of enhancing the release of an API and, thus, its bioavailability seems to be the use of liquid oil marbles (LOMs). An LOM system behaves as a solid form but consists...
Article
The manufacture of personalised medicines where specific combinations of active pharmaceutical ingredients (APIs) and their dose within a tablet would be adjusted to the needs of individual patients, would require new manufacturing approaches compared to the established practice. In the case of low-dose formulations, the required precision of API c...
Article
Full-text available
The problem of designing tablet geometry and its internal structure that results into a specified release profile of the drug during dissolution was considered. A solution method based on parametric programming, inspired by CAD (computer-aided design) approaches currently used in other fields of engineering, was proposed and demonstrated. The solut...
Article
Rapid tablet disintegration is a requirement for the efficient dissolution of the active pharmaceutical ingredient (API) from immediate release tablets. From the mechanistic viewpoint, tablet disintegration begins by the wetting of the tablet surface and the ingress of dissolution medium into the tablet pore structure, followed by the loosening of...
Article
Despite the wide application interest in mesoporous silica micro- and nano-particles and a number of synthesis routes reported in the literature, the question of chemical engineering scale-up of the synthetic routes has rarely been addressed. The present work reports the results of an experimental and computational study of batch scale-up by a fact...
Article
We report the synthesis of stable conductive macroporous materials by chemical oxidative polymerization of aniline-(2-acrylamido-2-methylpropanesulfonic acid) in the presence of polystyrene nanoparticles (PS-NPs). The presented method allows, without using any pore generating agent, to prepare conductive highly porous materials with tunable propert...
Article
Full-text available
A novel continuous fluidic method based on extractive crystallization for producing monodisperse spherical crystal aggregates with potential use in pharmaceutical engineering is presented. A model system of aqueous solution containing KCl as the precursor dispersed phase and 1-hexanol as the continuous extraction phase was investigated experimental...
Article
The combination of nanoparticles with the polymerase chain reaction (PCR) can have benefits such as easier sample handling or higher sensitivity, but also drawbacks such as loss of colloidal stability or inhibition of the PCR. The present work systematically investigates the interaction of magnetic iron oxide nanoparticles (MIONs) with the PCR in t...
Article
Composite porous silica-iron oxide nanoparticles with the ability to store chemical payloads and release them upon triggering a radiofrequency field were prepared. The particle structure consisted of a hollow porous silica core, covered with a layer of iron oxide nanoparticles bound to the silica surface by electrostatic forces. The particle size d...
Article
The fabrication of alginate hydrogel microparticles with embedded liposomes and magnetic nanoparticles for radiofrequency controlled release of encapsulated chemical cargo was considered. An extractive gelation process was implemented in a microfluidic device, which enabled the production of uniform composite microparticles of dimensions comparable...
Article
The ability to undergo a transition between dispersed or single-cellular state and aggregated or multi-cellular state provides distinct evolutionary advantages to many natural organisms. Due to a change of hydrodynamic diameter over several orders of magnitude and associated change of fluid–particle interaction (settling velocity) or intra-particle...
Article
The vapour-phase dehydration of ethanol over alumina has been considered as a model system for demonstrating a novel concept for the “remote control” of an endothermic catalytic reaction. Control of the reaction rate was achieved by forming composite catalyst pellets consisting of porous alumina with embedded metal (Fe) microparticles. Exposing suc...
Article
A method for controlled desorption by means of local heating due to high-frequency alternating magnetic field is described. The method has been demonstrated using three types of adsorbent–adsorbate systems: composite zeolite and silica-gel pellets for water adsorption, and activated carbon for the adsorption of toluene as a model volatile organic c...
Article
Full-text available
A thermoresponsive poly(N-isopropylacrylamide) (PNIPAM) hydrogel crosslinked with methylene bisacrylamide (MBA), with the ability to undergo a volume change of approximately 50%, was used to fabricate a hydrogel “sponge” with oil microdrops encapsulated within its structure by the polymerization of an O/W emulsion. By adding 1.5 wt.% of iron oxide...
Article
The structure and diffusion properties of composite particles consisting of a calcium alginate hydrogel core and a thin SiO(2) surface layer have been investigated. The composite particles were formed by depositing a silica layer onto calcium alginate cores using a sol-gel process starting from alkoxysilane precursors. The composite particles were...
Article
Full-text available
Poly(N-isopropylacrylamide) (PNIPAM) hydrogels crosslinked by methylene bisacrylamide (MBA) are known to exhibit a transition from hydrophilic to hydrophobic character at the lower critical solution temperature (LCST) of approximately 32 °C. This transition is normally accompanied by a volume change of the hydrogel. In this paper we describe a nove...
Article
Full-text available
The spreading, imbibition and solidification of a hot two-dimensional droplet on a cooler porous substrate is studied. Lubrication theory and asymptotic reduction are used to derive a coupled system of evolution equations for the droplet thickness and vertical extents of the solid/melt boundary and the saturation front within the porous medium. Thi...
Article
Full-text available
The influence of dc electric fields (EFs) on the development of buoyancy-driven instabilities of reaction fronts is investigated experimentally in a modified Hele-Shaw cell for the arsenous acid-iodate system. Assessment of effects of external EFs is made both visually and through dispersion curves. It is shown that density fingering, observed on a...
Article
Full-text available
The effects that applying constant electric fields have on the buoyant instability of reaction fronts propagating vertically in a Hele-Shaw cell are investigated for a range of electric field strengths and fluid parameters. The reaction produces a decrease in density across the front such that upwards propagating fronts are buoyantly unstable in th...
Article
Full-text available
Penicillin G (2%, w/v in phosphate buffer, pH8) was hydrolysed in a flow-through, miniature electro-membrane reactor with the penicillin G acylase immobilized in 5% (w/v) polyacrylamide (diam. 10mm, thickness 2.6mm, enzyme activity 24U ml–1). The conversion of penicillin G increased from 0.15 to almost 0.5 when the electric current applied to the r...

Network

Cited By