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Study of biodegradation of poly(hydroxy alkanoates).
Wurstová, Agáta ; Přikryl, Radek (referee) ; Obruča, Stanislav (advisor)
The master‘s thesis is focused on the study of biodegradation of polyhydroxyalkanoates, namely polymer polyhydroxybutyrate. The first part of the thesis is focused on the study of biodegradation of polyhydroxybutyrate in the form of crystalline granules of PHB and PHB films using selected species of microorganisms from bacteria, yeasts and fungi. As a representative of bacteria was chosen microorganism Delftia acidorovans, as yeast was selected Aureobasidium pullulans and Aspergillus fumigatus as fungi. PHB depolymerase activity was measured employing turbidemtiric method with suspension of PHB granules as substrate. The results showed that D. acidorovans can partially degrade PHB. On the contrary A. pullulans cannot effectively degrade PHB. The most significant degradation ability revealed A. fumigatus, which was able to degrade PHB completely. Extracellular enzymes excreted by these microorganisms when cultivated on PHB materials as sole carbon sources were analyzed by SDS-PAGE. The second part of the thesis deals with the biodegradation of PHB in the form of PHB film, PHB hardened foil and PHB Nanoul fabric using standard composting test. Semi-solid cultivation showed positive results. In the interval from 14 days to two months were all forms of the PHB completely biodegraded. With semi-solid cultivation was also studied biodegradation rate of the polyurethane elastomeric films which were modified by partial replacement of polyester polyol by PHB. The test samples were prepared using PHB from Sigma and the PHB samples prepared at the Faculty of chemistry VUT. Samples with different concentrations of the dispersed PHB (1 %, 5 % and 10 %) in the polyurethane were also object of the study. At the end of the cultivation (after 2 months) were measured mechanical properties in tension of the material, then efficiency of biodegradation by gravimetric analysis and modification of the material surface by microscopic analysis.
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The release of terbinafine from polyesters branched with polyacrylic acid
Jakubíková, Hana ; Šnejdrová, Eva (advisor) ; Dittrich, Milan (referee)
CHARLES UNIVERSITY Faculty of Pharmacy in Hradec Králové Department of Pharmaceutical technology Name of the student: Mgr. Hana Jakubíková Title of thesis: The release of terbinafine from polyesters branched with polyacrylic acid Consultant: PharmDr. Eva Šnejdrová, Ph.D. In this rigorous thesis, thermal and release properties of solid dispersions with terbinafine based on polyesters of lactic and glycol acid, branched with different concentration of polyacrylic acid, are studied and presented. Theoretical part summarizes current knowledge about terbinafine and its ways of application, advantages and disadvantages of solid dispersions and selection of a suitable polymeric carrier. In the experiment, solid dispersions were prepared by melting method, or solvent method using methyl-formate. The swelling rate and erosion rate were determined. The active pharmaceutical ingredient was incorporated into the polymer in form of hydrochloric salt or free base form in concentration of 10 %. Dissolution tests of terbinafine at 37 řC and pH 7.4 (phosphate buffer) were performed. Terbinafine concentration was determined spectrofotometrically at wavelength of 223 nm. Thermal analyses of solid dispersions revealed molecularly dispersed drug in concentration of 10 %. Polyesters degradation was running at pH 7,4 for...
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Study of the surfactants effect on polymer nanoparticle parameters
Moravcová, Katarína ; Holas, Ondřej (advisor) ; Šnejdrová, Eva (referee)
Charles University in Prague, Faculty of Pharmacy in Hradec Králové Department of Pharmaceutical Technology Consultant: PharmDr. Ondřej Holas, PhD. Student: Katarína Kostíková Title of thesis: Study of the surfactants effect on polymer nanoparticle parameters The main aim of this Diploma thesis was to examine whether the use of various stabilizers has any effect on the resultant size of prepared nanoparticles and to find out which type of stabilizer is the most appropriate in terms of preparation of the nanoparticles of the necessary size, adequate polydispersity and steadiness. The preparation of nanoparticles was based on the use of sodium cholate as a surfactant and polymer PLGA (poly (lactid-co-glycolic acid)) consisting of monomers of lactic and glycolic acids. Nanoparticles were prepared by means of nanoprecipitation method. Sodium cholate solution has always been prepared in water in different concentration: 0.005%, 0.01%, 0.02%, 0.05%, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 1%, 2%, and 5%. The following have been used as stabilizers: poloxamer 407, polyvinyl alcohol, cetrimonium-bromide (CTAB), and polysorbate 20, all of them in concentration of 0.1% and sorbitan-monostearate in concentration of 0.01%. Measurement of the size of created nanoparticles was performed using the device Zetasizer at the...
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Preparation of polymeric fluorescent nanopyrticles
Širajová, Daniela ; Holas, Ondřej (advisor) ; Svačinová, Petra (referee)
Charles University in Prague, Faculty of Pharmacy in Hradec Králové Department of Pharmaceutical Technology Consultant: PharmDr. Ondřej Holas, PhD. Student: Daniela Širajová Title of thesis: Preparation of polymeric fluorescent nanoparticles Nanoparticles based on biodegradable polyesters are a widely used platform for targeted drug delivery and subsequent controlled release. The aim of this diploma thesis was to prepare and optimize the preparation of polymeric nanoparticles with a fluorescent dye as a model substance. The nanoprecipitation method was used to prepare the nanoparticles. Nanoparticles prepared from two types of PLGA polymers (COOH terminated and ester terminated) were evaluated and compared. The surfactant and stabilizer were used in various concentration ratios to optimize the preparation. The surfactant was sodium cholate at concentrations of 0.1%, 0.5%, 1%, 2% and 5%. The nanoparticles were stabilized with Pluronic F-127 poloxamer at concentrations of 0.1%, 0.5% and 1%. Nanoparticles were compared in terms of encapsulation efficiency, particle size and zeta potential. In a dissolution experiment, the amount of fluorescein released was evaluated and compared as a function of time (48 hours) with acid-terminated PLGA and sodium cholate at concentrations of 0.1% and 2%....
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Study of the surfactants effect on polymer nanoparticle parameters
Kostíková, Katarína ; Holas, Ondřej (advisor) ; Šnejdrová, Eva (referee)
Charles University in Prague, Faculty of Pharmacy in Hradec Králové Department of Pharmaceutical Technology Consultant: PharmDr. Ondřej Holas, PhD. Student: Katarína Kostíková Title of thesis: Study of the surfactants effect on polymer nanoparticle parameters The main aim of this Diploma thesis was to examine whether the use of various stabilizers has any effect on the resultant size of prepared nanoparticles and to find out which type of stabilizer is the most appropriate in terms of preparation of the nanoparticles of the necessary size, adequate polydispersity and steadiness. The preparation of nanoparticles was based on the use of sodium cholate as a surfactant and polymer PLGA (poly (lactid-co-glycolic acid)) consisting of monomers of lactic and glycolic acids. Nanoparticles were prepared by means of nanoprecipitation method. Sodium cholate solution has always been prepared in water in different concentration: 0.005%, 0.01%, 0.02%, 0.05%, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 1%, 2%, and 5%. The following have been used as stabilizers: poloxamer 407, polyvinyl alcohol, cetrimonium-bromide (CTAB), and polysorbate 20, all of them in concentration of 0.1% and sorbitan-monostearate in concentration of 0.01%. Measurement of the size of created nanoparticles was performed using the device Zetasizer at the...
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Lyophilization of polymeric nanomaterials
Švehlíková, Ingrid ; Holas, Ondřej (advisor) ; Smékalová, Monika (referee)
Charles University in Prague, Faculty of Pharmacy in Hradec Králové Department of Pharmaceutical Technology Consultant: PharmDr. Ondřej Holas, PhD. Student: Ingrid Švehlíková Title od thesis: Lyophilization of polymeric nanoparticles Lyophilization is a widely used drying method with extensive application possibilities in the drug preparation. Its importance in pharmacy is growing because it is one of the important methods of stabilizing active substances, especially proteins. A detailed understanding of the properties of the drug and the physicochemical phenomena of the individual phases of lyophilization is a basic prerequisite for the preparation of a safe, effective and stable drug. Biomedical nanoparticles as drug carriers are the type of the dosage forms in which lyophilization is also used. A series of lyophilization experiments were performed using trehalose, mannitol, dextran and xylitol as cryo and lyoprotectant. The parameters assessed were particle size, PDI, appearance and lyophilisate reconstitution. The properties of nanoparticles prepared by nanoprecipitation from PLGA polymer were evaluated. Furthermore, experiments were performed to validate the deep-freezing method as an alternative method to lyophilization for long-term storage of nanoparticles. The nanoparticles were stored in...
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Preparation of polymeric fluorescent nanopyrticles
Širajová, Daniela ; Holas, Ondřej (advisor) ; Svačinová, Petra (referee)
Charles University in Prague, Faculty of Pharmacy in Hradec Králové Department of Pharmaceutical Technology Consultant: PharmDr. Ondřej Holas, PhD. Student: Daniela Širajová Title of thesis: Preparation of polymeric fluorescent nanoparticles Nanoparticles based on biodegradable polyesters are a widely used platform for targeted drug delivery and subsequent controlled release. The aim of this diploma thesis was to prepare and optimize the preparation of polymeric nanoparticles with a fluorescent dye as a model substance. The nanoprecipitation method was used to prepare the nanoparticles. Nanoparticles prepared from two types of PLGA polymers (COOH terminated and ester terminated) were evaluated and compared. The surfactant and stabilizer were used in various concentration ratios to optimize the preparation. The surfactant was sodium cholate at concentrations of 0.1%, 0.5%, 1%, 2% and 5%. The nanoparticles were stabilized with Pluronic F-127 poloxamer at concentrations of 0.1%, 0.5% and 1%. Nanoparticles were compared in terms of encapsulation efficiency, particle size and zeta potential. In a dissolution experiment, the amount of fluorescein released was evaluated and compared as a function of time (48 hours) with acid-terminated PLGA and sodium cholate at concentrations of 0.1% and 2%....
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The release of terbinafine from polyesters branched with polyacrylic acid
Jakubíková, Hana ; Šnejdrová, Eva (advisor) ; Dittrich, Milan (referee)
CHARLES UNIVERSITY Faculty of Pharmacy in Hradec Králové Department of Pharmaceutical technology Name of the student: Mgr. Hana Jakubíková Title of thesis: The release of terbinafine from polyesters branched with polyacrylic acid Consultant: PharmDr. Eva Šnejdrová, Ph.D. In this rigorous thesis, thermal and release properties of solid dispersions with terbinafine based on polyesters of lactic and glycol acid, branched with different concentration of polyacrylic acid, are studied and presented. Theoretical part summarizes current knowledge about terbinafine and its ways of application, advantages and disadvantages of solid dispersions and selection of a suitable polymeric carrier. In the experiment, solid dispersions were prepared by melting method, or solvent method using methyl-formate. The swelling rate and erosion rate were determined. The active pharmaceutical ingredient was incorporated into the polymer in form of hydrochloric salt or free base form in concentration of 10 %. Dissolution tests of terbinafine at 37 řC and pH 7.4 (phosphate buffer) were performed. Terbinafine concentration was determined spectrofotometrically at wavelength of 223 nm. Thermal analyses of solid dispersions revealed molecularly dispersed drug in concentration of 10 %. Polyesters degradation was running at pH 7,4 for...
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Aciclovir release from mucoadhesive polyester matrices
Jakubíková, Hana ; Šnejdrová, Eva (advisor) ; Dittrich, Milan (referee)
CHARLES UNIVERSITY IN PRAGUE Faculty of Pharmacy in Hradec Králové Department of Pharmaceutical technology Name of the student: Hana Jakubíková Title of diploma thesis: Aciclovir release from mucoadhesive polyester matrices Consultant: PharmDr. Eva Šnejdrová, Ph.D. The aim of this diploma thesis was to investigate aciclovir release from polyesters of lactic acid and glycolic acid branched with mannitol, pentaerythritol, dipentaerythritol and tripentaerythritol, and plasticized using ethyl pyruvate or methyl salicylate. Theoretical part sums up the application possibilities of mucoadhesive preparations. Experimental part of thesis deals with aciclovir release from polyester matrices applied on mucous substrate. Short term dissolution experiments of aciclovir were carried out in phosphate citrate buffer of pH 7, 4 at 37 řC. Mucus from porcine stomach was used as model substrate. The amount of aciclovir released was determined spectrophotometrically at 256 nm contrary to a blank sample, and also using HPLC method. Dissolution of aciclovir was affected by molar mass of polyester, and by the type and concentration of plasticizer. Polyester branched with 3 % of tripentaerythritol, and plasticizes by 40 % of methyl salicylate was found to be most suitable carrier of aciclovir for topical application on...
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Rheological properties of White Soft Paraffin
Hánová, Anna ; Šnejdrová, Eva (advisor) ; Šiška, Bedřich (referee)
CHARLES UNIVERSITY IN PRAGUE Faculty of Pharmacy in Hradec Králové Department of Pharmaceutical technology Name of the student: Anna Hánová Title of diploma thesis: Rheological properties of White Soft Paraffin Consultant: PharmDr. Eva Šnejdrová, Ph.D. This diploma thesis deals with the evaluation of consistency and rheological properties of the Soft Paraffin after viscosity modification by either Liquid or Solid Paraffin. The theoretical part focuses the characteristics and application of the hydrocarbon excipients, their use in pharmacy and comparison with other substances, rheological properties of semisolids and their consistency. Consistency by penetrometry according the Czech Pharmacopoeia 2009 and rheological properties using Kinexus rheometer were measured. Consistency of Soft Paraffin was significantly influenced with 5 % of Liquid Paraffin and 10 % of Solid Paraffin. The result of consistency assessment is significantly influenced by the method of the samples preparation. Rheograms and viscosity curves was constructed. Plastic systems were described in detail by the parameters of power law model and yield stress value. The addition of 5 % of Liquid Paraffin to the Soft White Paraffin caused the decrease of the coefficient of consistency and the flow index. A further addition of Liquid...
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