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Influence of stirring time on cosmetic stability
Grujić, Ksenija ; Sovová, Šárka (referee) ; Hurčíková, Andrea (advisor)
This bachelor thesis is based on the study of the influence of mixing time and revolutions per minute on the preparation of BB creams. The literature review of the thesis is based on the acquired information about the topic. The basic concepts and problems concerning dispersion systems, emulsions, mixing methods and cosmetics are described in this part of the thesis. The first segment of the experimental part is based on the preparation of BB creams themselves. The influence of agitation time and speed on the stability of prepared samples was tested. The stability of the samples was tested on LUMiSizer. The data were compared and processed.
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Granulometric characterisation of nanoparticles by the PCS method.
Jaworski, Jakub ; Dittrich, Milan (advisor) ; Šnejdrová, Eva (referee)
In the theoretical section of presented diploma thesis are discussed various nanoparticles such as micelles and liposomes, solid lipid nanoparticles and polymeric nanoparticles. Special attention was focused on copolymer PLGA. There are characterized different procedures in the preparation of nanoparticles. From the approches for nanoparticles evaluation are chosen measuring size of nanoparticles and their zeta potential. The experiment was almost unambiguously focused on study of effect of diffrent factors on nanopartlicles size and distribution from linear PLGA and PLGA used for branching of tripentaerythritol and polyacrylic acid. Keywords: nanoparticles, size, size distribution, zeta potential, interactions of nanoparticles
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Preparation of magnetorheological fluids with high sedimentation stability
Oharek, Lukáš ; Kalina, Michal (referee) ; Smilek, Jiří (advisor)
The introduced bachelor thesis focuses on the current issue of stability of magnetorheological fluids in the gravitation field. To prepare stable magnetorheological fluid, influence of additives, particles modification and different carrier fluid are investigated. Regarding the increased viscosity of the carrier fluids, which negatively affect the magnetorheological effect, a magnetorheological fluid containing carbonyl iron particles, which were chemisorbed with non-ionic surfactant Tween 20 was prepared. Mineral oil and water emulsions were used as a carrier fluid, emulsifier Span 80 was used to stabilize the water-in-oil emulsion. Sedimentation stability is improved, at the same time the viscosity of the carrier fluid is increased.
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Use of algae extracts in cosmetics
Plášková, Anna ; Rapta, Marek (referee) ; Márová, Ivana (advisor)
This thesis is focused on a preparation of extracts from selected species of algal and cyanobacterial strains, their characterization, a cytotoxicity testing and a use in cosmetic products. The theoretical part contains the review of a taxonomic classification and parameters of algae and cyanobacteria and basic information about used organisms. There is a description of the most significant factors influencing the algae cultivation and production of biomass. Further, active substances of algae and cyanobacteria, which could be used in cosmetic products as UV protective substances, were described. An overview of extraction techniques, encapsulation of active substance into liposomes and particles characterization, antioxidant activity analysis, and cytotoxicity tests is given too. In experimental part, antioxidant activity of algal extracts and chlorophyll a and carotenoid content were determined spectrophotometrically. The long-term stability of extracts was monitored for three weeks. Liposomes were prepared by sonification and encapsulation activity was analysed. The Dynamic Light Scattering method (DLS) was used for analysis of polydispersity and size of liposomes. Colloid stability of particles was determined by zeta potential. Cytotoxicity tests were performed using MTT assay. The prepared extracts, particles and lyophilized biomass of algal and cyanobacterial strain were further used as active substances in the formulation of cosmetic products (type o/w). These creams were tested on human skin.
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Encapsulation of plant extracts containing phenolic compounds into nanoparticles and nanofibers
Petrželková, Markéta ; Bokrová, Jitka (referee) ; Skoumalová, Petra (advisor)
The presented bachelor thesis was focused on the encapsulation of extracts containing phenolic substances in order to apply these materials in cosmetics. At work were prepared aqueous, ethanol and lipid extracts of coffee and cocoa. All extracts were characterized on the content of all polyphenols and flavonoids. Their antioxidant aktivity and SPF were also determined. Then the selected extracts were encapsulated into liposomes and polyhydroxybutyrate nanofibres. The basic characteristics of the prepared liposomes were also observed and also their SPF and antioxidant aktivity were monitored. The highest antioxidant aktivity and SPF had liposome particles containing ethanol cocoa extracts. The liposome particles were applied to cosmetic emulsion. These creams evince high antioxidant acitivity and stability determined by analytical centrifugation. Also the prepared nanofibres had high antioxidant aktivity and confirmed the gradual release of the active substances. In conclusion the test cytotoxicity on human keratinocytes confirmed the safety of prepared nanomaterials using the MTT test, which are therefore suitable for cosmetic applications.
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Particles with antimicrobial silver.
Svobodová, Dana ; Dittrich, Milan (advisor) ; Šnejdrová, Eva (referee)
Charles Univerzity in Prague Faculty of Pharmacy in Hradec Králové Department of Pharmaceutical Technology Candidate: Dana Svobodová Supervisor: doc. RNDr. Milan Dittrich, CSc. Diploma thesis title: Particles with antimicrobial silver The theoretical part of this diploma thesis outlines a brief overview of recent findings on silver nanoparticles. Further, it concerns the kinetic properties of colloidal systems, methods of evaluating the size and shape of colloidal particles, mechanism of antimicrobial activity of colloidal silver and methods of preparation of nanoparticles. Concise information about the toxicity of silver nanoparticles and their impact on the environment is also included. In the experimental part comprehensive report on the results of measurements of granulometric characteristics of microparticles and nanoparticles by photon correlation spectroscopy (PCS) is included. The influence of various modifications of preparation procedures and processing on stability, size and the polydispersity of the size in terms of the volume and intensity diameter of the particles with elemental silver deposited on the surface was studied. Optimisation of the disperse system, quality control of the content of colloidal particles by subsequent reduction, the possibilities of using centrifuge and...
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Influence of formulation factors on the polyester nanoparticles size.
Športeň, Radek ; Dittrich, Milan (advisor) ; Šnejdrová, Eva (referee)
In the theoretical part of this thesis are described various types of nanoparticles, such as polymeric particles, liposomes, micelles and solid lipid nanoparticles. There are presented basic informations concerning methods of particles preparation in the laboratory conditions such as solutions of polymers dispersion methods by intensively stirring, coacervation of the solutions of polymers, polymeration methods in dispersions, and the exploitation of methods of dispersion of polymeric solutions in the supercritical solvents. In the folowing part of this thesis are some concise informations about the methods of evaluation of basic parameters of the nanoparticulate systems. There are summarised the trivial informations concerning granulometry of particles, their zeta potential, encapsulation effectivity of drugs, and also about the particles shape factor. The focus of this thesis is in the experiment, the main deal were in minimisation of the particle size prepared by the method of emulsification of biodegradable aliphatic α-hydroxyacids polyesters solutions. The main process arrangement was the selection of the appropriate solvent of polymers in the inner emulsion phase and the founding for the mostly efficient emulsifier during the dispersion process of polymer solutions. In process of the...
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Granulometry of nanoparticles from aliphatic acids copolymers.
Šrejma, Robert ; Dittrich, Milan (advisor) ; Šnejdrová, Eva (referee)
The diploma thesis is focused on the study of influence on the composition of the system to the size of the nanoparticles from aliphatic polyesters with linear and branched molecules constitution. The emulsion method for distributing of solvent was chosen for preparation of nanoparticles. The theoretical part describes the nanoparticles, its origin and application. The following part is applying to biodegradable polymers, especially PLGA. There is also a mention of antifungal agent terbinafine. The nanoparticles are prepared of this substance. The process is described in the experimental part of thesis. The experimental part is testing different composition of samples. A main emphasis is on the choice of polymer solvent and emulsifier. There are also applied mixtures of solvents and emulsifiers. The important aspect is the evaluation of incorporated terbinafine, which has been the model drug. Prepared dispersions were exposed to stress conditions in the form of several days-storage and centrifugation.
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Preparation and characterization of cosmetic emulsion with addition of active compounds
Zinkovska, Natalia ; Smilková, Marcela (referee) ; Smilek, Jiří (advisor)
In the theoretical part, this bachelor’s thesis focuses on the overview of the basic characteristics and properties of the emulsion. Great attention is paid to choosing the type of emulsifier and the calculation hydrophilic-lipophilic balance. The mechanisms andcauses of instability of emulsions and their possible prevention and methods of stabilization are analyzed. The present state of the problem aimed to the analysis of existing methods for determination of emulsion stability and their use in practice is also part of this thesis. The experimental part of the work is primarily focused on the preparation of O/W cosmetic emulsions with additive of active substances such as UV absorbers. To characterize the prepared samples, pH values were measured and viscosities determined. The stability of the emulsion was carried out using an analytical centrifuge, and these results were further correlated with the standard gravitational stability tests (change of storage temperature of the formulation) according to the SÚKL methodical guidelines (REG-49, REG 51), which are the Czech version of the 75/318 /: Stability tests on active ingredients and finished products. Methods of preparation and composition of individual samples are described, which is further correlated with the stated characteristics of prepared creams.
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Preparation and characterization of biomaterials with natural UV filtres
Pavelková, Renata ; Čarnecká, Martina (referee) ; Márová, Ivana (advisor)
This presented diploma thesis is focuses on preparation and characterization of biomaterials with natural UV filters. The theoretical part is aimed at effects of sunlight on the skin and how to avoid these effects by using cosmetic products. The materials and methods for extraction of lipid part of the selected vegetable and microorganism species and methods for preparation and characterization of nanoparticles and emulsions were characterized. The practical part deals with extraction of lipid part of selected vegetable and microorganism species. The liposome particles with encapsulated active compounds were prepared. The particle size, polydispersity index, colloidal stability, encapsulation efficiency, SPF, antioxidant capacity, phospholipid content and cytotoxic effect on human keratinocytes were observed. These particles were used for preparation of the resulting emulsions. Their protection level on UV light were set and stability were tested by using analytical centrifugation.
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