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Optimization of 5-fluorouracil determination by high-performance liquid chromatography
Durychová, Eva ; Křížek, Tomáš (advisor) ; Kozlík, Petr (referee)
This thesis is dedicated to the development of a method for the determination of 5-fluorouracil by high-performance liquid chromatography, which could be used for determination of its encapsulation efficiency by liposomes. First, separation of 1 mM standard of 5-fluorouracil was tested on several types of columns. Among tested columns belonged a C18 column, a C18 column with positive surface modification, a phenyl-hexyl column and several fluoride columns together with two HILIC columns. A mixture containing 10 mM CH3COONH4, pH = 4,5 and MeOH in the ratio of 98/2 was initially used as the mobile phase. The results showed, that 5-fluorouracil elutes on all columns too close to the dead time, where different impurities often elute. To avoid possible distortion of 5-fluorouracil signal by impurities potentially occurring in the real sample, several adjustments of chromatographic conditions were tested. The most effective solution was addition of 5 mM ion-pairing agent (namely tetrabutylammonium chloride hydrate) to the mobile phase, together with adjusting pH to 8,0 to support the ionization of the analyte. In the combination with mobile phase modified in this way, a phenyl-hexyl column with retention time 4,36 minutes reached the best result, therefore it was selected for the final determination of...
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Methods of preparation and characterization of liposomal systems
Chýlková, Patricie ; Venerová, Tereza (referee) ; Jugl, Adam (advisor)
In this bachelor's thesis the properties of liposomes prepared by reference thin-film rehydration method and Mozafari method were compared. The aim of the experimental part was to determine whether the Mozafari method is convenient alternative for liposome preparation and whether thin-film rehydration and Mozafari methods produce liposomes with the same properties. The prepared liposomes were characterized in terms of size, polydispersity and zeta potential using dynamic light scattering on certain days for one month since the day of preparation. It was determined that electrostatically or sterically stabilized liposomes of identical composition prepared by either method had mutually corresponding properties.
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Optimization of Combined Chitosan Particles and their Characterization for Cosmetic use
Mrůzková, Barbora ; Dzurická, Lucia (referee) ; Bendová, Agáta (advisor)
The bachelor thesis focused on optimizing preparation and characterization of chitosan coated liposomes with selected active substances and their use for cosmetic applications. The theoretical part of the thesis describes natural substances, their effect on the skin, encapsulation methods, and the preparation and use of liposomes and chitosomes. In the experimental part, the optimization of the preparation of liposomes and chitosomes and their subsequent characterization by measuring particle size, polydispersity index, zeta potential, encapsulation efficiency and gradual release of active substances were performed. The selected active substances in this work were vitamin C, -carotene, caffeine and vitamin E. From the data obtained, the method of adding liposomes dropwise into the 2% chitosan with a short mixing time and ultrasonication for 1 minute was selected as the most suitable method for the preparation of chitosomes usable in cosmetics. Furthermore, the encapsulation efficiency of the particles and the antioxidant capacity of vitamin C, -carotene, caffeine and vitamin E were compared. The best antioxidant properties were determined for vitamins C and E; therefore, the gradual release of chitosomes with these active substances was subsequently measured in an environment simulating cosmetics. At the end of the work, cosmetic emulsions and gels containing selected chitosomes were prepared and tested on the skin by determining changes in desquamation.
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Rheological characterization of polysaccharide gels with incorporated vesicles
Kalendová, Lucie ; Smilek, Jiří (referee) ; Venerová, Tereza (advisor)
This diploma thesis deals with the rheological characterization of polysaccharide gels with incorporated vesicular systems. Positively charged Ion Pair Amphiphile vesicles (IPA) consisting of cetrimethylammonium bromide, sodium dodecyl sulfate, dioctadecyldimethylammonium chloride and cholesterol were chosen for the incorporation. Other vesicles used for incorporation were oppositely charged liposomes made of phosphatidylcholine (DPPC), phosphatidic acid (PA) and cholesterol. The thesis is divided into two sections. The first one deals with preparation, characterization and stability control (temperature and time stability) of both vesicular systems by using dynamic light scattering (DLS). In this part, the vesicles’ stability was confirmed which made them perfect candidates for the following incorporation. The second part of the thesis describes the preparation and rheological characterization of selected gels. Three types of gels were prepared in total, specifically 1% and 2% gellan gum gels and 4% hyaluronic gel. All of them were studied in water, as well as in solutions of IPA vesicles or DPPC liposomes, both of same concentration (1 mmoll-). The subsequent rheological characterization including amplitude, frequency, and stress relaxation sweeps demonstrates there is no significant difference between reference gels and those containing vesicles. This indicates that vesicles used in this thesis were only freely stored in the gel networks, meaning the structure of the gels didn’t affect their transport properties. This is a significant information for using these systems in drug delivery.
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Study of stability of antimicrobial nanomaterials in different environment by HPLC
Janderová, Šárka ; Trachtová, Štěpánka (referee) ; Márová, Ivana (advisor)
This thesis deals with the preparation of nanomaterials (nanoparticles, nanofibers) with encapsulated active substances and the stability of these nanomaterials in different environments using liquid chromatography. The development and optimization of methods for monitoring the kinetics of release of encapsulated substances from nanomaterials into various environments play a key role in research aimed at their utilization in the pharmaceutical, food, and cosmetic industries, and also contribute to the development of new antimicrobial nanomaterials limiting antibiotic resistance. The theoretical part focuses on the characterization of nanomaterials (nanoparticles, liposomes, nanofibers, and combined nanomaterials). Another section of the literature review deals with natural (eugenol, carvacrol, curcumin, thymol, vitamin E) and synthetic (ampicillin, streptomycin) antimicrobial substances. The final chapter discusses the instrumental methods used for the characterization of nanomaterials and the evaluation of their stability, released, and degradation products. In the practical part, the antioxidant activity of selected substances was first monitored. Liposomes were prepared, and their stability and encapsulation efficiency were examined. An HPLC method for determining active substances was optimized. Subsequently, the gradual release of the mentioned active substances from prepared liposomes was monitored. Nanofibers were prepared using forcespinning, and their release into selected model environments was also analyzed. Distilled water with minimal ion and impurity content served as a model environment, as well as a physiological solution at 25°C, simulating the temperature of the human body surface, and a physiological solution at 37°C, characteristic of human body temperature. This analysis provides a comprehensive view of the behavior of prepared materials and their potential practical applications. In the final section, combined nanomaterials (based on nanofibers and nanoparticles) with encapsulated active substances were prepared. The gradual release of active substances and any potential synergistic effects were examined for these nanomaterials.
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Preparation and characterization of nanoparticles with encapsulated antimicrobial component
Dohnalová, Marie ; Strečanská, Paulína (referee) ; Márová, Ivana (advisor)
This bachelor thesis is focused on the preparation and characterization of particles with encapsulated natural substances with antioxidant and antimicrobial properties. Selected antioxidants were anthocyanins, eugenol and vitamin E, as one of the most powerful antioxidants. At the same time, antimicrobial agents were chosen, in this case eugenol. In the theoretical part, individual active substances, materials for the preparation of particles, methods of their preparation were characterized and the principle of determining the safety of used materials. In the experimental part, selected active substances were characterized and the preparation of particles was optimized. Two types of liposomes were prepared, for which the encapsulation efficiency, size and stability were determined. Also prepared aqueous extracts of blueberries and blackberries were prepared, for which total anthocyanin content has been determined. The extracted substances from the plant material were encapsulated into alginate particles. Furthermore, the gradual release of active substances from particles into model environments using a spectrophotometer was determined. During the gradual release of active substances from the particles, the antioxidant effect was also monitored, in which it was possible to observe a decrease with the passage of time. The antimicrobial effect of active substances and liposomes against model microorganisms Escherichia coli and Micrococcus luteus was also tested. Cytotoxicity tests on human keratinocytes were performed on selected active substances, extracts and prepared nanoparticles, where it was proven that the selected materials are non-cytotoxic. Finally, a proposal for a possible application form in the form of an alginate hydrogel was created.
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Development of cosmetic products with antimicrobial effect
Dribňáková, Barbora ; Wikarská, Monika (referee) ; Márová, Ivana (advisor)
The proposed bachelor's thesis focuses on the preparation and study of nanomaterials with antimicrobial properties. The nanofibers were synthesized from biopolymers using the forcespinning method, and liposomes were prepared using the sonification method. Active ingredients used in this work are tymol, carvacrol, and eugenol. The theoretical section of the thesis discusses the methods for preparing nanofibers and nanoparticles and the materials required for their synthesis. It also covers the encapsulation of active ingredients in nanomaterials. Additionally, this part explores the skin microbiome, antimicrobial effects, and the use of both natural and synthetic antimicrobial agents. The practical part of the thesis focuses on determining the polyphenol content and antioxidant activity of each active ingredient. The gradual release of active ingredients into saline solution and distilled water was determined for nanofibers synthesized from polyhydroxybutyrate with encapsulated active ingredients. Furthermore, it deals with the optimization of nanofiber synthesis from chitosan and polyamide using the forcespinning method. The functionalized liposomes were characterized in terms of their size, stability, encapsulation efficiency, and gradual release of active ingredients. The liposomes showed high stability even after several weeks, and their size ranged from 170.90 ± 1.63 nm to 243.07 ± 7.83 nm. Finally, the antimicrobial activity of the prepared products and active ingredients was tested against Cutibacterium acnes, Staphylococcus epidermidis, and Escherichia coli. The tested active ingredients in pure and encapsulated form, demonstrated antimicrobial effect against both gram-positive and gram-negative bacteria. We assume the possibility of using the prepared nanomaterials in cosmetic products intended for the treatment of acne and other skin diseases, and also its use in the form of preservatives.
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Optimization of Combined Chitosan Particles and their Characterization for Application Use
Netopilík, Tibor ; Hudečková, Helena (referee) ; Márová, Ivana (advisor)
The thesis deals with the preparation and characterization of nanoparticles for cosmetic and food applications. The thesis explores various methods of preparing nanoparticles, including liposomes and chitosomes, and analyses their properties and stability in different model environments. The experimental part includes the determination of the encapsulation efficiency of different vitamins by HPLC and UV-VIS spectrophotometry. Results show the influence of various factors such as time, type of environment and method of preparation on stability and efficiency of the nanoparticles. Furthermore, the optimization of the preparation is carried out chitosomes using ultrasound and magnetic stirrer. Cosmetic products enriched with these nanoparticles were developed and their sensory analysis was proved. This work contributes to the understanding of nanoparticle preparation processes and provides useful information for the development of new cosmetic and food products with improved properties and stability.
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Isolation of active compounds from algae and their application in cosmetic products
Nováková, Laura ; Byrtusová, Dana (referee) ; Skoumalová, Petra (advisor)
The bachelor thesis is dedicated to the study of active substances and antioxidant effects of cultivated microalgae. We compared the results with a commercial alga that is freely available. In the theoretical part we focused on description of algal metabolites in cosmetics and a brief description of the methods used in their testing. In the experimental part there were analyzed three types of extracts (aqueous, alcohol and oil) from 4 species of algae. It is mainly the content of polyphenols, flavonoids and antioxidant activity that is determined. According to the results, the highest content of active substances was found in oil extracts. All extracts were encapsulated into liposomes. The average size of the nanoparticles was in range of 200 nm to 300 nm. The particles were stable enough also for long-term stability. The largest decrease was observed in the oil extract of the cultivated algae Chlorella vulgaris. The cytotoxicity of oil extracts was realized by MTT test on human cell cultures HaCaT. Finally, we concluded that the prepared liposomal particles could be used for anti-aging cosmetics.
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