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Human skin explants as models for research of skin barrier functions
Kašparová, Petra ; Paraskevopoulou, Anna (advisor) ; Kováčik, Andrej (referee)
Charles University, Faculty of Pharmacy in Hradec Králové Department of Pharmaceutical Technology Supervisor: PharmDr. Anna Paraskevopoulou, Ph.D. Author: Petra Kašparová Title of the thesis: Human skin explants as models for research of skin barrier functions The skin protects the human organism from harmful environmental effects and maintains the stability of the internal environment of the human body. The protective function is considered the most important role of the skin. It is provided primarily by the uppermost layer of the epidermis, the stratum corneum (SC). The arrangement of the lipid layer surrounding keratinocytes is especially important for it. This is evidenced by the association between the increased incidence of skin diseases and the imbalance of present lipids. This thesis deals with the development of an ex vivo model of human skin, which would be used in the future to investigate skin barrier and topically administered formulations. The aim of this thesis is to establish suitable ex vivo skin cultivation conditions to achieve its sufficient viability and at the same time the biosynthesis of skin lipids. Initially, it was necessary to determine whether the adjustment of the skin graft thickness by dermatome is advantageous for their viability. Furthermore, the culture was...
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Effect of the number of lipid layers on the properties of thin films as skin barrier models.
Bělochová, Šárka ; Pullmannová, Petra (advisor) ; Paraskevopoulou, Anna (referee)
Charles University, Faculty of Pharmacy in Hradec Králové Department of Biophysics and Physical Chemistry Mentor: Mgr. Petra Pullmannová, Ph.D. Student: Šárka Bělochová Title of Thesis: Effect of the number of lipid layers on the properties of thin films as skin barrier models The uppermost layer of the skin, the stratum corneum (SC), primarily serves a barrier function that is essential for human survival on dry land. The SC is composed of flattened dead cells, corneocytes, which are surrounded by an extracellular lipid matrix. The composition and arrangement of SC lipids are closely related to the proper structure and function of the skin, and their disruption can lead to the development of certain skin diseases. The study aimed to determine the effect of the number of lipid layers on the properties of thin films as skin barrier models. The method used for the preparation of the models was the deposition of thin films by the Langmuir-Blodgett technique. Mono-, tri- and five-layer models were prepared. The deposited sample was a mixture simulating the composition of skin lipids and containing ceramides, cholesterol and a mixture of fatty acids in a molar ratio of 1:0.45:1. These models were then evaluated by atomic force microscopy (AFM) and Raman microspectroscopy. During the experiments,...
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The effect of ceramide structure on the behavior of thin films modeling the skin barrier.
Šustrová, Terezie ; Pullmannová, Petra (advisor) ; Kováčik, Andrej (referee)
Charles University, Faculty of Pharmacy in Hradec Králové Department of Biophysics and Physical Chemistry Student: Terezie Šustrová Mentor: Mgr. Petra Pullmannová, Ph.D. Title of Diploma Thesis: The effect of ceramide structure on the behavior of thin films modeling the skin barrier The skin barrier is essential for human survival on dry land, it is located in the uppermost layer of the skin, in the stratum corneum (SC). SC consists of corneocytes that are surrounded by an oligolamellar lipid matrix. The main components of the SC lipids are ceramides (Cer), fatty acids (FFA) and cholesterol (Chol). They are found in the SC in a ratio of 1:1:1. This ratio is essential for epidermal homeostasis. Any change in this ratio may lead to disruption of the barrier function, e.g. to the development of atopic dermatitis or psoriasis. These lipids prevent excessive loss of water from the body and the entry of undesired substances from the external environment into the body. The lipid matrix forms a typical lamellar arrangement in the skin. Lipids form structures with a long periodicity phase - LPP (d ~ 13 nm), with a short periodicity phase - SPP (d ~ 6 nm) and a separated Chol phase (d ~ 3,4 nm). The molecules are organized with each other in a lateral arrangement that can be orthorhombic, hexagonal, or...
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Study of conjugates of sphingolipids with hyaluronic acid and their application on the skin
Juhaščik, Martin ; Kováčik, Andrej (advisor) ; Gajdziok, Jan (referee) ; Miletín, Miroslav (referee)
1 ABSTRACT Charles University, Faculty of Pharmacy in Hradec Králové Training Workplace Department of Pharmaceutical Technology Doctoral Degree Program Pharmaceutical Technology Candidate Mgr. Martin Juhaščik Supervisor doc. PharmDr. Andrej Kováčik, Ph.D. Advisor Gloria Huerta-Ángeles, Ph.D. Title of Doctoral Thesis Study of conjugates of sphingolipids with hyaluronic acid and their application on the skin The main goal of this study was to systematically design and subsequently prepare conjugates of hyaluronic acid (HA) with selected sphingolipids, which could find application in their topical administration during physiological decline of skin functions. In this study, phytosphingosine and ceramide were chemically linked to HA via biocompatible linkers, enabling successful modification of HA into a hydrophobized conjugate of sphingolipid-linker-hyaluronate. The preparation of succinylceramide-hyaluronate conjugate was found to be the most effective. The developed method of preparing the conjugate using mixed anhydrides brings several advantages, including the possibility of scaling up the preparation and conducting reactions in an aqueous environment. The method was effective over a wide range of molecular weights, from 6 to 442 kgmol-1, achieving a degree of substitution of up to 14.2 %, surpassing the...
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Laboratory Measurements of Skin Conductance
Slouka, Petr ; Harabiš, Vratislav (referee) ; Sekora, Jiří (advisor)
This thesis contains an introduction to anatomy and physiology of the skin highlighting its barrier function. The barrier function of the skin enables it to separate internal organism from external environment. thermore, the electrical properties of the skin are described and possibilities of skin conductance measurement are discussed. The thesis presents a design of a device for the skin conductance measurement as the method of evaluation for barrier function. Alternating current is used for measurement during iontophoresis for evaluation of skin conductance. Circuit design and circuit board are included with a list of parts. The designed device was realized and in the end it was tested and the results were discussed.
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Experimental study and modelling of the transdermal penetration of active species from gels
Palanová, Veronika ; Opatřilová, Radka (referee) ; Sedláček, Petr (advisor)
This diploma thesis deals with design and experimental study of transdermal transport of pharmaceutically active agents from gel matrices, which contain humic substance in its structure. A model absorption membrane was represented by the skin of pig´s earlobes. The study of the release of active substances and Lignohumte was performed due to the vertical diffusion cells. The amount of released humic substance was characterized by UV-VIS method and the amount of released active agent from gel matrix was determined by HPLC-DAD. The most interesting finding of this diploma thesis was that Lignohumate enhances transdermal transport of active agents and supports their release from gel samples to the particular environment.
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Study of penetration of selected substances from elderberry extracts through biological membrane
Škubalová, Zuzana ; Němcová, Andrea (referee) ; Vespalcová, Milena (advisor)
This Diploma thesis focuses on the study of penetration of selected phenolic substances contained in extract from black elder (Sambucus nigra) via modelling systems represented by two types of synthetic membranes and a real system represented by a biological membrane. As a biological membrane, we have chosen skin from pig´s earlobe. Experiments of transdermal absorption and absorption through synthetic membranes were conducted through vertical (Franz´s) cells. Selected substances contained in the extract from black elder were rutin and chlorogenic acid. The main focus of this work was to determine how readily, or if at all, these two selected phenolic substances penetrate the skin and selected synthetic membranes. The percentage of absorbed amount of the substance was determined by HPLC analysis.
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Study and Evaluation of Topically Applied Ceramides onto Disrupted Skin Barrier
Svobodová, Marie ; Kováčik, Andrej (advisor) ; Vraníková, Barbora (referee)
Department of Pharmaceutical Technology Author: M S b S , Ph.D. Title of diploma thesis: Study and Evaluation of Topically Applied Ceramides onto Disrupted Skin Barrier Skin is the largest organ of the human body and serves several key functions, such as protection against external influences and regulation of body temperature. Healthy skin is able to maintain the integrity and stability of the organism due to its complex structure. The skin is composed of several layers of cells, including the stratum corneum (SC), which forms the main protective barrier. Ceramides (CER) are one of the main types of barrier lipids found in the SC. These lipid molecules, along with other lipids, create a hydrophobic matrix that protects the skin from dehydration and other external influences. The lack of CER in the skin barrier leads to the disruption of its function and the worsening of the skin condition. This is associated with many diseases, such as dermatitis, psoriasis, and others. The study of CER in the SC is important to understand the mechanisms of skin protection and to develop new therapeutic approaches for the treatment of skin diseases. Topical administration of barrier lipids, especially CER, is one possible treatment route for skin diseases. Therefore, the aim of this work was to prepare...
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Interaction of PAMAM dendrimers with the human stratum corneum
Žofková, Kateřina ; Paraskevopoulou, Anna (advisor) ; Svačinová, Petra (referee)
Charles University, Faculty of Pharmacy in Hradec Králové Department of Pharmaceutical Technology Supervisor: PharmDr. Anna Paraskevopoulou, Ph.D. Author: Kateřina Žofková Title of the thesis: Interaction of PAMAM dendrimers with human stratum corneum Dendrimers are highly branched, monodisperse macromolecules. On the basis of the degree of branching, can be distinguished different generations of dendrimers that arise as the dendrimers expand. Higher generations of dendrimers form spherical structures with an internal cavity, where molecules such as a drug can be encapsulated. Due to their structure, which can be specifically and controllably modified, dendrimers are investigated for their use in biomedicine. One of the most widely used groups of dendrimers are polyamidoamine (PAMAM) dendrimers, based on an ethylenediamine core, branched amide and amine units, and terminal functional groups. PAMAM dendrimers with amine groups have proven useful in the past as skin penetration enhancers of different drugs. However, the mechanism how these molecules affect skin barrier function is not yet known. Therefore, in this work was investigated the mechanism of interaction of PAMAM dendrimers with lipids of stratum corneum (SC), the uppermost skin layer where the skin barrier is found. Second, third and...
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Influence of cholesterol concentration on permeability and microstructure of model skin barrier lipid membranes
Červená, Martina ; Vávrová, Kateřina (advisor) ; Zbytovská, Jarmila (referee)
Cholesterol is a substance of a steroidal nature that has a number of functions in the human body. One of them is also an irreplaceable role in the proper functioning of the skin barrier. Cholesterol is an integral part of the lipid matrix, together with ceramides and free fatty acids in an equimolar ratio (1: 1: 1), and 5% cholesterol sulfate, which fills the intercellular space between stratum corneum cells and is responsible for the barrier properties of the skin. Cholesterol is therefore necessary for epidermal homeostasis, but its role in SC permeability is unknown. The aim of this work was to study the influence of cholesterol concentration on the permeability and microstructure of model lipid membranes of the skin barrier. Eight sets of model membranes with decreasing cholesterol concentrations (100%, 80%, 70%, 60%, 40%, 20%, 0%) and cholesterol alone were studied for which permeability and microstructure were monitored.The study of permeability of membranes was carried out in the Franz diffusion cells by measuring four permeation parameters: water loss, electrical impedance measurement, and the cumulative amount of two model drugs (theophylline and indomethacin). The microstructure of these model membranes was verified by X-ray powder diffraction. X-ray powder diffraction measurements...
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