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Rheological behavior of branched polyesters
Martiška, Juraj ; Šnejdrová, Eva (advisor) ; Holas, Ondřej (referee)
CHARLES UNIVERSITY IN PRAGUE Faculty of Pharmacy in Hradec Kralove Department of Pharmaceutical technology Name: Juraj Martiska Title of diploma thesis: Rheological behavior of branched polyesters Supervisor: PharmDr. Eva Snejdrova, Ph.D. This thesis studies rheological and thermal properties of potencial polyester drug carrier composed of an equimolar proportion of D,L-lactic and glycolic acids, branched with tripentaerythritol at a concentration of 3%, and its analogs plasticized with methyl salicylate at different concentrations. The theoretical part deals with the characterization of polymers, their plasticizing and rotational rheometry. In the experimental part were prepared plasticized polyesters then were determined their glass transition temperatures using a DSC, and on rotational rheometer was tested their rheological behavior. According to the results of thermal analysis, methyl salicylate significantly lowers the glass transition temperature of the tested polyester and seems to be suitable plasticizer. The resulting data of rheological analyzes show that 3T plasticized polymer exhibits pseudoplastic behavior at 25řC and concentration of methyl salicylate 20% when the viscosity is highest. Viscosity of polymer systems significantly decreases with increasing temperature and concentration...
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Medicated polymer systems based on branched PLGA derivatives
Martiška, Juraj ; Dittrich, Milan (advisor) ; Kubová, Kateřina (referee) ; Kvítek, Libor (referee)
Charles University, Faculty of Pharmacy in Hradec Králové Department of Pharmaceutical technology Candidate Mgr. Juraj Martiška Supervisor doc. RNDr. Milan Dittrich, CSc. Title of Doctoral Thesis Medicated polymer systems based on branched PLGA derivatives This work is focused on the use of originally synthesized poly(DL lactic-co-glycolic acid) (PLGA) derivatives with relatively low molar mass, and linear, star, or comb architecture as promising biodegradable carriers for prolonged or targeted drug release systems. Thermal properties of these polyesters were evaluated by thermogravimetric analysis and differential scanning calorimetry. Polyesters were used for nanoparticles formulation by nanoprecipitation method, which has been optimized with emphasis on organic solvent selection, polyester concentration, phase mixing speed, and stabilizer selection. After method optimization, nanoparticles with encapsulated terbinafine, a typical drug of the BCS class II, were prepared. Multiple parameters such as particles size, polydispersity index, zeta potential, encapsulation efficiency, loading capacity, and morphology were monitored. Spherical morphology was observed using scanning electron microscopy. The hydrophobicity and the polyester concentration revealed the main impact on the nanoparticles size...
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Rheological behavior of branched polyesters
Martiška, Juraj ; Šnejdrová, Eva (advisor) ; Holas, Ondřej (referee)
CHARLES UNIVERSITY IN PRAGUE Faculty of Pharmacy in Hradec Kralove Department of Pharmaceutical technology Name: Juraj Martiska Title of diploma thesis: Rheological behavior of branched polyesters Supervisor: PharmDr. Eva Snejdrova, Ph.D. This thesis studies rheological and thermal properties of potencial polyester drug carrier composed of an equimolar proportion of D,L-lactic and glycolic acids, branched with tripentaerythritol at a concentration of 3%, and its analogs plasticized with methyl salicylate at different concentrations. The theoretical part deals with the characterization of polymers, their plasticizing and rotational rheometry. In the experimental part were prepared plasticized polyesters then were determined their glass transition temperatures using a DSC, and on rotational rheometer was tested their rheological behavior. According to the results of thermal analysis, methyl salicylate significantly lowers the glass transition temperature of the tested polyester and seems to be suitable plasticizer. The resulting data of rheological analyzes show that 3T plasticized polymer exhibits pseudoplastic behavior at 25řC and concentration of methyl salicylate 20% when the viscosity is highest. Viscosity of polymer systems significantly decreases with increasing temperature and concentration...
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