National Repository of Grey Literature 113 records found  beginprevious112 - 113  jump to record: Search took 0.01 seconds. 
Encapsulation of caffeine
Patočková, Klára ; Pekař, Miloslav (referee) ; Márová, Ivana (advisor)
This bachelor thesis is focused on possibilities of encapsulation caffeine in micro- and nanoparticles. In the theoretical part was devoted to information about caffeine, liposomes and polysaccharides and also on the techniques of encapsulation. In the experimental part 5 different methods were used for preparation of micro- and nanoparticles with encapsulated caffeine. Caffeine was packaged into liposomes and polysaccharide particles (chitosan/alginate). Encapsulation’s effectiveness was determined by HPLC/UV-VIS. Prepared particles were monitored for size and stability by dynamic light scattering. The particles were exposed to the arteficial stomach and intestinal juices and bile acids. Particle stability and amount of released caffeine was monitored. Analytical centrifugation was used to measurement of sedimentation velocity and stability of the prepared particles. Caffeine containing particles were added in several soft drinks to determine particles amount when turbidity occurred.
Characterization and stabilization of pancreatin
Wurstová, Agáta ; Němcová, Andrea (referee) ; Obruča, Stanislav (advisor)
This work focuses on a study of enzyme mixture pancreatin, its characterization and subsequent encapsulation into liposomes. As a reference proteins bovine serum albumin and trypsin were used. Characterization of pancreatin consisted of two parts. The first part focuses on optimization of methods for the concentration determination by absorption spectrophotometry using basic methods for identifying proteins (Biuret method, Hartree-Lowry method and Bradford method). Moreover, UV spectrums of the protein were measured. As a method for identification of protein´s molecular weight, SDS-PAGE was used. To identify components of pancreatin, LPLC was employed in two modifications, ion-exchange chromatography and size exclusion chromatography. The second part is dedicated to the characterization of pancreatin as enzyme in terms of pH and temperature optimum for the enzyme activities of protease (pH 9, 8 and 50 °C), amylase (pH 7 and 40 °C) and lipase (pH 7 and 50 °C). The last part of this work aimed at an encapsulation of pancreatin into liposomes and DLS analysis of distribution of particles and their zeta potential. Liposomes did not spontaneously release encapsulated enzyme. To confirm that proteins were successfully entrapped into liposomes, their structure was disrupted by application of phospholipase D. In conclusion, liposomes can be utilized as delivery systems for native enzymes.

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