National Repository of Grey Literature 23 records found  previous11 - 20next  jump to record: Search took 0.01 seconds. 
Pharmaceutical applications of polyesters as drug nanocarriers
Staňková, Petra ; Holas, Ondřej (advisor) ; Paraskevopoulos, Georgios (referee)
Charles University Faculty of Pharmacy in Hradci Králové Department of Pharmaceutical Technology Consultant: PharmDr. Ondřej Holas, PhD. Student: Petra Staňková Title of Thesis: Pharmaceutical applications of polyesters as drug nanocarriers Nanoparticles are nowadays intensively studied and perspective type of a drug carrier. Its potential is based on a possibility of targeted drug delivery and controlled drug release. The theoretical part is about nanoparticles types, polymers derived from α-hydroxyacids (PLA, PGA, PLGA). Focus is given on methods of nanoparticles preparation: dispersion of preformed polymers or the polymerization of monomers. The modification of particles surface and practical use of nanomedicine in healthcare are described in other chapters. The research in experimental part is focused on the influence of different types of PLGA and their weighing on the size, polydispersity, nanoparticles zeta potential and encapsulation efficiency of rhodamine B. Nanoparticles were prepared by nanoprecipitation method or by solvent evaporation method. The Zetasiser ZS 90 device was used to measure the size of the nanoparticles and to measure zeta potential. The result of the research shows the most suitable weighing for creation of nanoparticles is 25 mg. The samples of this weighing show a...
Polymeric pharmaceutical nanoparticles preparation: a process optimization
Bárta, Michal ; Holas, Ondřej (advisor) ; Vraníková, Barbora (referee)
Charles University, Faculty of Pharmacy in Hradec Králové Department of: Pharmaceutical Technology Consultant: PharmDr. Ondřej Holas, Ph.D. Student: Michal Bárta Title of Thesis: Preparation of pharmaceutical nanoparticles: optimalization process Pharmaceutical, polymer nanoparticles besides others work as well as a drug carriers. Their uniqueness is not only because of their subcelular size, but as well because of the biodegradability and biocompatibility they hold. The benefit of these nanoparticiples is the possibility of creation of selective naoparticiples which are able to controle long-term release. The formulation of polymer nanoparticles can be reached within methods using preformed polymer or with polymerization of monomers. The main goal of my thesis was to optimize the production process of polymer nanoparticles and the observation of the solvent influences. The methods used for this reaserch were evaporation method and nanoprecipitation. Granulometric and electrical characteristics of particles were measured with Zetasizer ZS 90. Measurements have prooved, that it is preferable to use the nanoparticle method for the prepartion of the the small nanoparticles with low polydispersity and sufficient stability. From the results of the granulometric analysis of nanoparticles made by the...
Formulation and testing of siRNA-loaded branched polyesters nanoparticles
Medviďová, Simona ; Dittrich, Milan (advisor) ; Šnejdrová, Eva (referee)
Charles University Faculty of Pharmacy in Hradcec Králové Department of Pharmaceutical Technology Supervisor: doc. RNDr. Milan Dittrich, CSc. Student: Simona Medviďová Title of thesis: Formulation and testing of branched polyesters siRNA-loaded nanoparticles The progression of development increases demand for new and more effective drug systems formulations. This diploma thesis is focused on the preparation of nanoparticles from biodegradable branched polyesters based on PLGA, which are suitable for the transport of an oligonucleotide of a small interfering nucleic acid, siRNA. The theoretical part focuses on the characteristics of usable polymers, their possible modifications, the methods of preparation with closer look at the selected nanoprecipitation method, the important parameters such as particles size, zeta potential, and polydispersity. The main part is also characterization of siRNA in terms of structure, properties, modifications, and its function. A more extensive experimental part deals with the appropriate choice of type and concentration of polyester and stabilizer, methods of preparation and characterization of nanoparticles, and the possibility of analyzing encapsulated siRNA. Chapters results and discussion compares polyesters branched on tripentaerythritol, and polyacrylic acid...
Biodegradable polymeric nanoparticles preparation
Bacskaiová, Silvia ; Holas, Ondřej (advisor) ; Dittrich, Milan (referee)
Charles University in Prague, Faculty of Pharmacy in Hradec Králové Department of: Pharmaceutical technology Consultant: PharmDr. Ondřej Holas, Ph.D. Student: Silvia Bacskaiová Title of Thesis: Biodegradable polymeric nanoparticles preparation The present scientific progress in an important rate conduces to nanomedicine development, which aims to reengineering of cancer pharmacotherapy and other substantial diseases. The main intention of this graduation thesis is the study of surface-active chemical's effects on the final properties of nanoparticles. The theoretical part is focused on the nanoparticles likedrugs vehicles, synthesis of biodegradable nanoparticles, themselves applications in the cancer therapy, diseases accompanied by inflammations, vaccination and for another different purposes. The theoretical part also contents characterization of active and passive goal- directed distribution by diseases, microencapsulations, synthesis of nanoparticles by polymerization and from previously synthesized polymers and definition of physical- chemical properties of nanoparticles. The experimental part is more extensive and concerned with the optimalization of reaction conditions of nanoparticles synthesis, with selection of advisable concentracion and type of surfactant. In the experimental part were...
Polymeric pharmaceutical nanoparticles preparation: a process optimization
Bárta, Michal ; Holas, Ondřej (advisor) ; Vraníková, Barbora (referee)
Charles University, Faculty of Pharmacy in Hradec Králové Department of: Pharmaceutical Technology Consultant: PharmDr. Ondřej Holas, Ph.D. Student: Michal Bárta Title of Thesis: Preparation of pharmaceutical nanoparticles: optimalization process Pharmaceutical, polymer nanoparticles besides others work as well as a drug carriers. Their uniqueness is not only because of their subcelular size, but as well because of the biodegradability and biocompatibility they hold. The benefit of these nanoparticiples is the possibility of creation of selective naoparticiples which are able to controle long-term release. The formulation of polymer nanoparticles can be reached within methods using preformed polymer or with polymerization of monomers. The main goal of my thesis was to optimize the production process of polymer nanoparticles and the observation of the solvent influences. The methods used for this reaserch were evaporation method and nanoprecipitation. Granulometric and electrical characteristics of particles were measured with Zetasizer ZS 90. Measurements have prooved, that it is preferable to use the nanoparticle method for the prepartion of the the small nanoparticles with low polydispersity and sufficient stability. From the results of the granulometric analysis of nanoparticles made by the...
Pharmaceutical applications of polyesters as drug nanocarriers
Staňková, Petra ; Holas, Ondřej (advisor) ; Paraskevopoulos, Georgios (referee)
Charles University Faculty of Pharmacy in Hradci Králové Department of Pharmaceutical Technology Consultant: PharmDr. Ondřej Holas, PhD. Student: Petra Staňková Title of Thesis: Pharmaceutical applications of polyesters as drug nanocarriers Nanoparticles are nowadays intensively studied and perspective type of a drug carrier. Its potential is based on a possibility of targeted drug delivery and controlled drug release. The theoretical part is about nanoparticles types, polymers derived from α-hydroxyacids (PLA, PGA, PLGA). Focus is given on methods of nanoparticles preparation: dispersion of preformed polymers or the polymerization of monomers. The modification of particles surface and practical use of nanomedicine in healthcare are described in other chapters. The research in experimental part is focused on the influence of different types of PLGA and their weighing on the size, polydispersity, nanoparticles zeta potential and encapsulation efficiency of rhodamine B. Nanoparticles were prepared by nanoprecipitation method or by solvent evaporation method. The Zetasiser ZS 90 device was used to measure the size of the nanoparticles and to measure zeta potential. The result of the research shows the most suitable weighing for creation of nanoparticles is 25 mg. The samples of this weighing show a...
Formulation and testing of siRNA-loaded branched polyesters nanoparticles
Medviďová, Simona ; Dittrich, Milan (advisor) ; Šnejdrová, Eva (referee)
Charles University Faculty of Pharmacy in Hradcec Králové Department of Pharmaceutical Technology Supervisor: doc. RNDr. Milan Dittrich, CSc. Student: Simona Medviďová Title of thesis: Formulation and testing of branched polyesters siRNA-loaded nanoparticles The progression of development increases demand for new and more effective drug systems formulations. This diploma thesis is focused on the preparation of nanoparticles from biodegradable branched polyesters based on PLGA, which are suitable for the transport of an oligonucleotide of a small interfering nucleic acid, siRNA. The theoretical part focuses on the characteristics of usable polymers, their possible modifications, the methods of preparation with closer look at the selected nanoprecipitation method, the important parameters such as particles size, zeta potential, and polydispersity. The main part is also characterization of siRNA in terms of structure, properties, modifications, and its function. A more extensive experimental part deals with the appropriate choice of type and concentration of polyester and stabilizer, methods of preparation and characterization of nanoparticles, and the possibility of analyzing encapsulated siRNA. Chapters results and discussion compares polyesters branched on tripentaerythritol, and polyacrylic acid...
Control of the morphology of biodegradable polymer blends
Ostafińska, Aleksandra ; Šlouf, Miroslav (advisor) ; Kosek, Juraj (referee) ; Vohlídal, Jiří (referee)
This dissertation, entitled »Control of the morphology of biodegradable polymer blends«, has been running parallel with the grant project »Multiphase biodegradable polymer systems« and it represents a new research direction in the Department of morphology and rheology of polymer materials at the Institute of Macromolecular Chemistry. The main idea was to employ our long-lasting work and experience in the field of morphology control of synthetic polymer blends in the very analogous field of the biodegradable polymer blends. We have chosen three most common, widely used and relatively cheap bio-based polymers - starch, poly(lactic acid) and poly(ε-caprolactone) - in order to investigate how the properties of their blends might be improved if we control the blend morphology in targeted, reproducible and well-defined way from the very beginning. It has been well established that morphology (phase structure, supramolecular structure) is one of the key factors influencing final properties of polymer blends, including mechanical performance, rate of (bio)degradation, gas permeability etc. In this work, numerous preliminary experiments showed that there are two systems in which the morphology control could significantly help in the improving of their end-use properties: PLA/PCL/TiX (where PLA = poly(lactic acid),...
The Application of Separation Techniques Based on Gas and Liquid Chromatography with Different Types of Detectors for the Determination of Biologically Active Compounds and Selected Xenobiotics
Mravcová, Ludmila ; Hajšlová, Jana (referee) ; Kráčmar, Stanislav (referee) ; Chýlková,, Jaromíra (referee) ; Vávrová, Milada (advisor)
This work deals with the using and application of separation techniques for analysis of polymers degradation and polycyclic aromatic hydrocarbons. Thereby this work is separated to two special parts. In the first part, the degradation properties of synthetic biopolymers based on lactic acid, gylcolic acid and poly(ethyleneglycol) PLGA-PEG-PLGA and ITA-PLGA-PEG-PLGA-ITA (modified by itaconic acid) were studied. These copolymers (firstly their thermosensitive hydrogels) should be used for therapy of fractures in orthopedy (as adhesives). Therefore, the sol-gel and gel-sol phase diagrams were determinated for selected samples of copolymers. The samples forming gel at 37 C was used for other study. Polymer samples were depredated in phosphate buffer at 37°C. The degradation process of physical hydrogels was described by the decrease of molecular weight and the increase of concentration lactic acid and glycolic acid in phosphate buffer. The obtained results confirmed that the degradation of polymer modified by itaconic acid is faster process than no modified polymer and polymers with lower ratio PLGA/PEG degrade also faster than lower ration PLGA/PEG. The influence of pH it was also tested. The rate of degradation of polymers was follow pH 4,0
Rheological properties of biodegradable thermosensitive copolymers
Chamradová, Ivana ; Poláček, Petr (referee) ; Vojtová, Lucy (advisor)
Hlavním cílem předložené diplomové práce byla příprava, charakterizace a reologická studie "inteligentních" injektovatelných hydrogelů, které jsou biodegradovatelné, biokompatibilní a s řízenou životností sestávajících se z hydrofilního polyethylenglykolu (PEG) a hydrofobního kopolymeru kyseliny polymléčné a polyglykolové (PLA/PGA). Výsledný termosenzitivní PLGA–PEG–PLGA kopolymer, který geluje při teplotě lidského těla, byl dále funkcionalizován anhydridem kyseliny itakonové získané z obnovitelných zdrojů, přinášející jak reaktivní dvojné vazby tak i funkční –COOH skupiny na konce kopolymeru. Navíc byl PLGA–PEG–PLGA kopolymer modifikován bioaktivním anorganickým hydroxyapatitem pro použití jako injektovatelné kostní adhezivum. Oba modifikované kopolymery jak ITA/PLGA–PEG–PLGA/ITA tak i PLGA–PEG–PLGA/HAp ovlivňují reologické vlastnosti původního PLGA—PEG—PLGA kopolymeru rozhodující o tom, zda by mohly být nové polymerní materiály vhodné jako injektovatelné nosiče léčiv nebo kostní lepidla v lékařských aplikacích. Experimentální část této práce je zaměřena především na charakterizaci viskoelastických vlastností jak nemodifikovaného PLGA—PEG—PLGA kopolymeru tak i s přidáním ITA nebo HAp metodou obrácených testovacích vialek (TTIM) a dynamickou reologickou analýzou. Výhodou TTIM je vizualizace přechodu sol-gel, určení kritické gelační teploty a kritické gelační koncentrace. Reologická měření poskytují informace o viskozitě a vizkoelasticitě gelu změnou elastického (G´) a ztrátového (G´´) modulu. Připravené kopolymery byly také charakterizovány 1H NMR a GPC. Povrch a velikost částic HAp byl popsán pomocí SEM a laserového analyzátoru částic. Původní PLGA—PEG—PLGA kopolymer i kopolymer modifikovaný ITA a HAp vykazovaly sol-gel přechod vyvolaný zvýšením teploty. Reologické vlastnosti kopolymerů v koncentračním rozmezí 6 až 24 hm. % ve vodě byly studovány buď TTIM nebo užitím reometru a získané výsledky spolu velmi dobře korespondovaly. Reologické vyhodnocení prokázalo dvě „překřížení“, kde G´ =G´´. První překřížení velmi dobře korespondovalo s prvním sol-gel přechodem nalezeným prostřednictvím TTIM. Maximální hodnota G´ odpovídající nejvyšší tuhosti polymerního gelu byla situována v bílém gelu. Druhý fázový přechod představuje přechod mezi gelem a suspenzí, kdy je bílý polymer oddělen od vody. Tuhost gelu roste s rostoucí koncentrací polymeru ve vodě. Pro srovnání, kopolymer modifikován jak ITA, tak i přidáním HAp (0, 10, 20, 30, 40, 50 hm %) vykázal zvýšení tuhosti gelu oproti původnímu kopolymeru PLGA–PEG–PLGA a přiblížení teploty maximální hodnoty G´ tělesné teplotě (37 °C). Bylo prokázáno, že jak ITA/PLGA–PEG–PLGA/ITA kopolymer tak i PLGA—PEG—PLGA/HAp kompozit jsou vhodnými kandidáty na injekovatelné systémy pro řízené uvolňování léčiv či kostní adhezivum pro ortopedii nebo zubní aplikace.

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