National Repository of Grey Literature 41 records found  beginprevious24 - 33next  jump to record: Search took 0.00 seconds. 
Study of free sphingoid bases in skin barrier
Jarešová, Zuzana ; Kováčik, Andrej (advisor) ; Vraníková, Barbora (referee)
Charles University, Faculty of Pharmacy in Hradec Králové Department of Pharmaceutical Technology Author: Zuzana Jarešová Supervisor: PharmDr. Andrej Kováčik, Ph.D. Consultant: PharmDr. Lukáš Opálka, Ph.D. Title of diploma thesis: STUDY OF FREE SPHINGOID BASES IN SKIN BARRIER The skin barrier, localized in the stratum corneum (SC), consists of corneocytes and an intercellular matrix formed from three types of lipids - ceramides, free fatty acids, and cholesterol, represented in an equimolar ratio. The overall arrangement of lipids is organized and highly specialized. Ceramides are structurally formed from the fatty acid acyl attached to a sphingoid base. In minor but not insignificant amounts, free sphingoid bases can also be found in the skin barrier. Several studies show that there is an increased concentration of free sphingoid bases in skin barrier disorders, such as atopic dermatitis. Although it is assumed that the presence of free sphingoid bases affects the skin barrier, it is not elucidated the way of their participation till today. The lack of studies or their diverse results leads us to the main goal of this thesis - to clarify how free sphingoid bases influence the skin barrier. In this work, the model membranes were prepared by the isolation of human SC ex vivo. Sphingosine (S),...
Investigation of process parameters and their influence on spray dried particles properties
Grázová, Marcela ; Svačinová, Petra (advisor) ; Kováčik, Andrej (referee)
1. ABSTRACT Charles University, Faculty of Pharmacy in Hradec Králové Department of: Pharmaceutical Technology Supervisor: PhamDr. Petra Svačinová, Ph.D. Consultant: Ing. Petr Koukal, Ph.D. Student: Marcela Grázová Title of Thesis: Investigation of process parameters and their influence on spray dried particles properties. The aim of the thesis was to determine to what extent it is possible to influence the particle size of the products by setting the parameters of the dryer. This particle size largely depends on the scale of the dryer used. Therefore, the aim was to determine whether a laboratory-scale spray dryer can either produce particles of variable size or particles of such size, that is typically obtained from production-scale devices. Particles prepared of meloxicam dispersions in hydroxypropylmethylcellulose phthalate were used for evaluation. A variety of input parameters for spray drying (drying gas inlet temperature, stock solution flow, concentration, and spray nozzle diameter) was used to prepare several batches of the product. The methodology Design of Experiments was used to identify the influence of individual input parameters on the product properties (particle size, glass transition temperature, and residual solvent content). Individual batches of the products were characterized by 1 H...
Calcium phosphate bone cements: Synthesis, Characterization and drug release properties
Doubek, Jiří ; Paraskevopoulos, Georgios (advisor) ; Kováčik, Andrej (referee)
Charles University, Faculty of Pharmacy in Hradec Králové Department of Pharmaceutical Technology Author: Jiří Doubek Supervisor: Dr. Georgios Paraskevopoulos, Ph.D. Title of Thesis: Calcium phosphate bone cements: Synthesis, characterization and drug release properties Non-healing bone traumas are currently a complication, which may disable a patient from active life for a long period. Due to the fact that bone mass consists mostly of hydroxyapatite, a derivative of calcium phosphate - calcium phosphate cement (CPC) - is studied as an injectable bone substitute. The cement's characteristics (low setting temperature, injectability, bioactivity, and resorbability) are very promising. Furthermore, the possibility to incorporate a drug in the formulation that would support the healing process opens a way for new therapeutic options. Firstly, the aim of this research was to synthesize a high-quality α-tricalcium phosphate (α-TCP) and characterize its properties. Subsequently, the prepared α-TCP was used for the preparation of an injectable and washout resistant cement paste. Finally, the properties of developed pure or ibuprofen-loaded cement were examined by X-ray diffraction, Raman spectra, compressive strength, scanning electron microscopy, and dissolution studies. The obtained data revealed that...
In vitro study of topical use of cidofovir
Sedláčková, Martina ; Vávrová, Kateřina (advisor) ; Kováčik, Andrej (referee)
Martina Sedláčková In vitro study of topical use of cidofovir Pharmaceutical faculty in Hradec Králové, Charles University Abstract Cidofovir (CDV), an antiviral drug belonging to the group of acyclic nucleoside phosphonates, is a highly potent drug used for treatment of various infections of viral origin. The low usage of CDV is caused by its price. This work deals with possibilities of increasing the concentration and availability of CDV r in the skin that could lead to lowering of the production costs of the preparations containing this substance. The goal of this work was to study the concentration of CDV in different skin layers after its application on intact and tape striped human skin. The effect of permeation enhancer 6-(dimethylamino)hexanoic acid dodecyl ester was also investigated. Both attitudes were investigated in vitro using modified Franz diffusion cells. Three different concentration of CDV (0.3%, 1% and 3%) were applied on the intact or tape-stripped skin with or without 1% enhancer. In intact skin, the combination of 3% CDV with 1% enhancer provided epidermal CDV concentration of 1115 µg/g, which is 1.45-times higher than without an enhancer. In tape-striped skin, the epidermal concentration of CDV increased to 2584 µg/g which is 1.55-times higher than without enhancer. The highest...
Calcium phosphate bone cements: Synthesis, Characterization and drug release properties
Doubek, Jiří ; Paraskevopoulos, Georgios (advisor) ; Kováčik, Andrej (referee)
Charles University, Faculty of Pharmacy in Hradec Králové Department of Pharmaceutical Technology Author: Jiří Doubek Supervisor: Dr. Georgios Paraskevopoulos, Ph.D. Title of Thesis: Calcium phosphate bone cements: Synthesis, characterization and drug release properties Non-healing bone traumas are currently a complication, which may disable a patient from active life for a long period. Due to the fact that bone mass consists mostly of hydroxyapatite, a derivative of calcium phosphate - calcium phosphate cement (CPC) - is studied as an injectable bone substitute. The cement's characteristics (low setting temperature, injectability, bioactivity, and resorbability) are very promising. Furthermore, the possibility to incorporate a drug in the formulation that would support the healing process opens a way for new therapeutic options. Firstly, the aim of this research was to synthesize a high-quality α-tricalcium phosphate (α-TCP) and characterize its properties. Subsequently, the prepared α-TCP was used for the preparation of an injectable and washout resistant cement paste. Finally, the properties of developed pure or ibuprofen-loaded cement were examined by X-ray diffraction, Raman spectra, compressive strength, scanning electron microscopy, and dissolution studies. The obtained data revealed that...
Permeation of nanoparticles through sublingual membrane 3
Dvořáková, Pavlína ; Doležal, Pavel (advisor) ; Kováčik, Andrej (referee)
Charles University in Prague, Faculty of Pharmacy in Hradec Králové Department of pharmaceutical technology Candidate: Mgr. Dvořáková Pavlína Consultant: doc. RNDr. Pavel Doležal, CSc. Title of Thesis: Permeation of nanoparticles through sublingual membrane 3. In the theoretical part, attention was paid to the entry of drugs into the body by the sublingual route, description of the oral cavity (mucosa, epithelium, mucus, saliva, MCGs), OCCAT model, and basic concepts of bioimpedance. In the experimental part, the hydrodynamic size of the PD-Chromeon 470 nanoparticles was verified by the DLS method. In the environment of water, even two buffers pH 6.8 and 7.4 according to Sörensen, practically identical results were obtained at the level of 40 nm. Buffers were used as donor, resp. acceptor phase in vitro permeation experiments. The experiments included measurement of impedances of differently processed and stored sublingual membranes from pig tongue. To test the penetration of nanoparticles through these model mucosal barriers, nanoparticles were applied in a concentrated (500 µg / ml), diluted (1: 4) dispersion. The lowest impedance had the sodium azide-preserved membranes, which were frozen at -18 ř C for a long time. These also showed the highest in vitro permeation values of nanoparticles. Rapid...
Effect of temperature and solution concentration on the properties of spray-dried lactose using the nozzle with diameter of 2 mm.
Pavelková, Nikola ; Svačinová, Petra (advisor) ; Kováčik, Andrej (referee)
Charles University, Faculty of Pharmacy in Hradec Králové Department of: Pharmaceutical technology Consultant: PharmDr. Petra Svačinová, Ph.D. Student: Nikola Pavelková Title of Thesis: Effect of temperature and solution concentration on the properties of spray-prepared lactose using the nozzle with diameter of 2 mm Spray drying is a method used in various industry fields. The principle is the conversion of a substance in the liquid state into solid dry particles. By spray drying it is possible to obtain a suitable product with the desired properties, which depends on the various process parameters. The aim of the work is to determine the influence of temperature and concentration of the solution on the properties of spray-prepared lactose using a nozzle with a diameter of 2 mm. Solutions of 15 % and 20 % lactose were prepared and dried at inlet temperatures of 150 - 210 řC. The shape and size of obtained particles were examined by optical microscopy. Thermal properties were evaluated using differential scanning calorimetry. At 15 % concentration, most of the spray-dried lactose particles occurred in the size range 2,5 - 5 μm and 5 - 7,5 μm . At a concentration of 20 % it was between 2,5 - 5 μm. For both concentrations the minimum numbers of particles were smaller than 2,5 μm and larger than 15 μm....
Effect of glucosyl sphingosine on the stratum corneum permeability
Bataalla, Omar Mahrous Farid ; Kováčik, Andrej (advisor) ; Svačinová, Petra (referee)
Charles University, Faculty of Pharmacy in Hradec Králové Department of pharmaceutical technology Candidate: Omar Mahrous Farid Bataalla Supervisor: PharmDr. Andrej Kováčik, Ph.D. Consultant: Dr. Georgios Paraskevopoulos, PhD. Title of Thesis: Effect of Glucosyl Sphingosine on the stratum corneum Permeability Glucosyl sphingosine (GSP) belongs to a large lysolipid subclass of sphingolipids, which is formed from ceramide (Cer) precursors by its hydrolysis. Patients with some skin diseases, such as atopic dermatitis, have lower amounts of barrier Cer in comparison to a healthy skin. As a result, they have higher quantity of GSP with low moisture content due to impaired barrier function. The aim of my work was to investigate the effect of GSP on skin permeability (in this thesis, the uppermost epidermal layer, the stratum corneum, was used) by using four permeability markers, trans-epidermal water loss (TEWL), electrical impedance, flux of theophylline and flux of indomethacin. The electrical impedance showed higher permeability to ions in tissues with GSP (statistically significant) in comparison to the controls. An addition of GSP also increased the permeability to water, small polar molecules and large lipophilic molecules (both statistically insignificant). I also investigated the role of GSP on...
Effect of sphingosine phosphorylcholine on the stratum corneum permeability
Bataalla, Khalied Mahrous Farid ; Kováčik, Andrej (advisor) ; Vraníková, Barbora (referee)
Charles University Faculty of Pharmacy in Hradec Králové Department of pharmaceutical technology Candidate: Khalied Mahrous Farid Bataalla Supervisor: PharmDr. Andrej Kováčik, Ph.D. Adviser: Dr. Georgios Paraskevopoulos, PhD. Title of Diploma Thesis: Effect of Sphingosine Phosphorylcholine on the stratum corneum Permeability Sphingosine phosphorylcholine (SPC) is a sphingolipid, which belongs to a lysolipid family. This compound, formed from ceramide precursor - sphingomyelin by the action of sphingomyelin deacylase, is composed of sphingoid base (e.g., sphingosine) and phosphorylcholine moiety joined to a hydroxyl group. In this project, we studied how SPC influences the barrier function and microstructure of model stratum corneum (SC) membranes. Four permeability markers were used to study the permeability of SPC: electric impedance, trans-epidermal water loss (TEWL), flux of indomethacin and flux of theophylline. From this study we found out that the addition of SPC significantly increases the permeability to water and ions (increased values of TEWL and decreased values of electric impedance). This trend was also observed on third (permeability to theophylline) and fourth (permeability to indomethacin) permeation markers. The detrimental effect of SPC was also studied in biophysical experiments...
Study of microstructure of skin barrier model using deuterated ceramides
Juhaščik, Martin ; Kováčik, Andrej (advisor) ; Paraskevopoulos, Georgios (referee)
Charles University, Faculty of Pharmacy in Hradec Králové Department of Pharmaceutical Technology Author: Martin Juhaščik Supervisor: PharmDr. Andrej Kováčik, Ph.D. Title of diploma thesis: Study of microstructure of skin barrier model using deuterated ceramides Ceramides (Cer) are sphingolipids, which participate in eucaryotic cells in various biological processes (cell signalling, proliferation, differentiation and cell apoptosis). In mammalian skin, Cer are localized in the uppermost layer of epidermis, stratum corneum (SC). In this layer, Cer along with cholesterol (Chol) and free fatty acids form multilayer lamellae of intercellular lipid matrix. The skin lipid arrangement in SC is still unclear. To evaluate the skin lipid arrangement, skin membrane models with labelled (deuterated) lipids have been used. Therefore, the aim of this work was to synthesize sphingosine with deuterated chain and Cer based on deuterated sphingosine, i.e., N-lignoceroyl sphingosine-d28 (with lignoceric acid acyl (C24); d-CerNS) and N-lignoceroyl-d47 sphingosine-d28 (dd-CerNS) and to study their phase behaviour and arrangement in model membranes by using biophysical studies. Synthesis of deuterated Cer started from elimination of 1-pentadecanol-d31 to obtain a deuterated terminal alkene. Next, a vinylation of...

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