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Nanofiber membranes as carriers of drugs 6.
Bidmonová, Hana ; Doležal, Pavel (advisor) ; Vachek, Josef (referee)
Rigorous thesis Nanofiber membranes as carriers of drugs 6. Mgr. Hana Bidmonová ABSTRACT Thesis deals with the evaluation of absorption and the release properties of the nanofibre membranes that were prepared using electrospinning of chitosan solution with the contents of 5 % of a drug and covered with polyurethane layer. Thesis brings a survey about the use of nanofibre membranes in pharmacy and medicine, especially their characteristics and application at drug delivery and distribution and in tissue engineering. The ability of three different membranes to accept and release caffeine as a model drug from their structure was investigated. The caffeine was incorporated into the membranes in company Elmarco, Liberec, or it was impregnated in the membranes using absorption from solutions containing drug. A hypothesis concerned with ability of membranes to accept a part of caffeine by another mechanism than an amount incorporated before electrospinning was confirmed. All of three membranes were immersed in media containing caffeine and they adsorbed the drug in quantity dependent on the sort of liquid medium. At the use of the chloroform dispersions of caffeine, membranes adsorbed more then a mass of membranes themselves. In the set of release experiments of membranes the released amount of caffeine...
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Nanofiber Membranes as Drug Carriers 5.
Beneš, Michal ; Vachek, Josef (referee) ; Doležal, Pavel (advisor)
M. Beneš Abstract The theoretical part of this work deals with chitosan polymer and its derivates. A polymer molecule is described in more detail, its solubility and chemical modifications are described separately. In the next part biocompatibility and biodegradability of chitosan are dealt with. Parameters of the electrospinning of chitosan end this chapter. The experimental part is first dedicated to the determination of aquosity in the samples of 3 different nanofiber membranes and to their gravimetric changes by keeping in the desiccator. The samples of membranes absorb water at the most up to 1,5% (m/m) and there is not a big difference among them. The second part quantifies changes in the composition of the saturated excipients which were used for the impregnation of the samples of nanomembranes. The highest amount of caffeine was absorbed by the membrane 3, namely in case of both saturating media. The evaluation of the amount of caffeine which the tested membranes are able to release from their surface in vitro follows. In case of the saturation of membranes by the aqueous solution of caffeine and by the caffeine suspension is the maximum of the subsequent liberation into the acceptor phase reached from the 120th minute. In case of the ethanolic and chloroform saturated solution is the maximal...
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Study of the Termotropic Behaviour of Short-chain Ceramid Analogues
Vavrysová, Helena ; Zbytovská, Jarmila (advisor) ; Doležal, Pavel (referee)
Ceramides of stratum corneum (SC) play a crucial role in maintaining the barrier function of the skin. This work deals with series short-chain analogues of ceramides with structure identical to naturally occuring ceramide NS, acyl chain length from 2 to 12. Acyl chain length is very important for barrier properties. Ceramides with chain length 4-8C lose barrier function, conversely were able to increase skin peremability. Ceramides with 2 and 12C showed no increase in permeability. Calorimetric and infrared spectroscopic measuring data were used for studying thermotropic phase behaviour analogues of ceramides and compared to the physiological cermide NS. At physiological temperatures, all crystalline phases of ceramides exhibit lamellar structures with highly ordered hydrocarbon chains. Structure-activity relationships and potential permeable aktivity of these ceramides were observed. Short-chain ceramides do not act as natural ceramides and their biological activity has been widely investigated.
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The methodical study of tensiometric evaluation of transdermal enhancers.
Lasák, Roman ; Doležal, Pavel (advisor) ; Musilová, Marie (referee)
1 SOUHRN V teoretické části byl podán stručný přehled fyzikálně-chemických vlastností tenzidů, hlavně chování na fázovém rozhraní a v objemové fázi. Pozornost byla věnována také charakteristice transkarbamu 12, arlasolvu, transcutolu a také cholesterolu. Zároveň tato část obsahuje obecné rozdělení metod měření povrchového napětí, podrobně je vysvětlen princip měření povrchového napětí kroužkovou metodou na tenziometru Krüss K100. V experimentální části byly nejprve ověřeny vlastnosti zadaných enhancerů ve vodném prostředí. Bylo zjištěno, že transkarbam 12 je tenzidem. Poté se zkoumalo jeho chování v prostředí trispufru 7,1. Zde povrchové napětí se stoupající teplotou roste a hodnoty CMC se několikanásobně zvětují v porovnání s vodným prostředím, poloha Kraftova bodu se posunula do vyšších teplot než je 25řC. Dále byly zkoumány interakce cholesterolu a T12 v prostředí trispufru 7,1 a to u vzorků udržovaných na vodní lázni za stálého míchání a temperace, a u vzorků stacionárně inkubovaných v biologickém termostatu za stálé teploty. Bylo zjištěno, že u vzorků stacionárních k vytváření rovnováhy, která není narušována mícháním a vznikající částice tak s časem rostou, což se odráží na velikosti povrchového napětí. Vzorky T12 s cholesterolem snižují povrchové napětí více než vzorky bez jeho obsahu. Cholesterol s...
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The study of thermotropic phase behaviourof pseudoceramide 14S24 and its mixtures with cholesterol.
Toningerová, Lenka ; Zbytovská, Jarmila (advisor) ; Doležal, Pavel (referee)
A study of the thermotropic phase behaviour of the pseudoceramide 14S24 and its mixture with cholesterol Abstract The thermotropic phase behaviour of mixture of ceramide analogue 14S24 with cholesterol was scoped in this diploma thesis. The samples were measured under non-hydrated and hydrated conditions for the various ratios of 14S24. Two methods were used for the measurement and determination, namely DSC and Infrared spectroscopy. The phase transitions and the changes in a structure of the ceramide analogue 14S24 were studied. The influence of concentration on temperature was monitored by DSC. Interestingly, the eutectic mixture occurred with 30% content of ceramide analogue 14S24. Furthermore, a hydration of the mixture influenced its melting point by means of decrease. The crystalline lattice was determined by IR showing triclinic or optional hexagonal structure.
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Thermal analysis of interaction of epidermal lipids I.
Kafková, Veronika ; Musilová, Marie (advisor) ; Doležal, Pavel (referee)
Termální analýza interakcí epidermálních lipidů Ι Veronika Kafková, diplomová práce, červen 2007 Abstrakt Fyziologickou funkcí kůže je chránit organismus proti vnějším vlivům prostředí. Stratum corneum (rohová vrstva) je nejsvrchnější vrstvou kůže a je zodpovědná za její bariérovou funkci. Podstatou chování rohové vrstvy je její jedinečné chemické složení a uspořádání jednotlivých složek. Rohová vrstva je tvořená plochými, do sebe zapadajícími buňkami vyplněnými keratinem (korneocyty) a intercelulární lipidovou matrix. Hlavními složkami lipidové matrix jsou ceramidy (50%), mastné kyseliny (10%) a cholesterol (25%). Cílem této diplomové práce je experimentální ověření možnosti využití diferenční skenovací kalorimetrie (DSC), jako vhodné a sensitivní metody pro měření in vitro směsí lipidů obsažených ve stratum corneum. Změřili jsme a vyhodnotili DSC záznamy vzorků mastných kyselin (kyseliny olejové, linolové, myristové, palmitové) a cholesterolu, směsí mastné kyseliny a cholesterolu (1:1,m/m), dvousložkových směsí kyseliny olejové a cholesterolu (v poměrech od 1:9 do 9:1) a směsí kyseliny olejové, cholesterolu a vody. DSC je vhodná a sensitivní metoda pro tato měření, jejíž velkou výhodou je rychlost a velmi malá spotřeba množství vzorku. The thermal analysis of interactions of epidermal lipids Ι Veronika...
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Optimization of rheological properties of the decontaminating hydrophobic microemulsions.
Běhávková, Vendula ; Doležal, Pavel (advisor) ; Šnejdrová, Eva (referee)
Optimalization of rheological properties of the decontaminating hydrofobic microemulsions Behavkova Vendula Aim: To prepare stable hydrofobic microemulsions which would be able to decontaminate chemical warfare agents. Methods: Testing and selecting individual components which together create a stable microemulsion. As a hydrophobic phase were tested tetrachloroethylene, toluene, decahydronaphthalene and heptane, as surfactants cationactive, anionactive and nonionic compounds and as cosurfactants butanol and hexanol. As a hydrophilic phase was at first tested water and then in stable microemulsions water was changed by alkaline solution of H2O2. Results: With water was prepared probably 800 emulsions. For testing with alkaline solution of H2O2 was chosen 24 best microemulsions according to their stability, optical brightness and amount of hydrophilic phase. With 0,1M alkaline solution of H2O2 was prepared 20 microemulsions and with the 1M concentration of the same solution was prepared 14 microemulsions. These microemulsions can represented a base of the decontaminating compounds in experiments in vivo. The attention was paid mainly to cationic surfactants, here was expected accelerating of the hydrolitic reaction because of micromedium at micellar surface, which is able to concentrate...
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The methodical study of transdermal in vitro delivery of drugs.
Uhlířová, Eva ; Doležal, Pavel (advisor) ; Berka, Pavel (referee)
A methodic study of transdermal in vitro delivery of drugs. Abstract The master thesis brings a short outline of transdermal bioequivalence. The possibility of the using of an in vitro permeation experimental design to quantification of transkarbam 12 as the enhancer in dermatologic creams of a real composition was evaluated using pig ear skin model and caffeine as the permeation marker.
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Effect of Lipophilicity of Substrates and Surfactants on the Efficiency of Micellar Hydrolysis of p-N-nitrofenylalkanoates with Alkylpyridinium Bromides
Běhávková, Vendula ; Vachek, Josef (referee) ; Doležal, Pavel (advisor)
Rigorosum Thesis 2010, Vendula Běhávková Abstract The subject of this work was to verify if a homologous series of N-alkylpyridinium substances and p-nitrophenylcarbonates possess the reciprocal influence of the length of alkyl chains on the rate of hydrolytic reaction. In a series of N-alkylpyridinium substances was tested pyridinium bromide with alkyl chain lengths of C10, 12, 14, 16 and C18. These surfactants were tested with p-nitrophenyl acetate, -butyrate, -caprylate, -caprate, -laurate, -myristate, -palmitate and-stearate. The highest values throughout the group results were achieved through a combination of p-nitrophenyl-caprate and octadecylpyridinium bromide. 5x10-3 M concentration of surfactant was able to accelerate the decomposition of p-nitrophenyl-caprate 120 times and almost reached the rate constant 0.0878 sec-1 , which corresponds to the half-life is approximately 8 seconds. octadecylpyridiniumbromide and hexadecylpyridinium bromide were proved as successful micellar catalysts. The best hydrolysable substrates were medium-length alkylated.
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