National Repository of Grey Literature 108 records found  1 - 10nextend  jump to record: Search took 0.01 seconds. 
Mobility of pharmaceuticals in soil systems
Slaninová, Kristína ; Širůček, David (referee) ; Klučáková, Martina (advisor)
As a result of improper disposal, pharmaceuticals from households, industry or hospitals are discharged into the environment. Another source through which pharmaceuticals enter the environment is the fertilization of the soil with organic fertilizers or other natural fertilizers containing animal excreta. Medications penetrate into the environment through sewage, entering wastewater, groundwater, surface water, drinking water, and soil, posing an environmental threat. Chelating properties of the organic component of soil could potentially be a solution to the problem of medication presence in soil by preventing migration of the medication. Sulfathiazole is among the group of medications frequently detected in the environment. Sulfathiazole is a sulfonamide antibiotic primarily used in veterinary medicine. The aim of this bachelor's thesis is to determine the concentration profile of sulfathiazole in the soil column and to identify its diffusion coefficients. The thesis also includes a study of the sorption and desorption of sulfathiazole in soil.
Modeling migration of pharmaceuticals
Osipenko, Ivan ; Závodská, Petra (referee) ; Klučáková, Martina (advisor)
The presented bachelor thesis deals with the problem of the possibility of sulfapyridine diffusion in soil systems. The main objective of this thesis is to propose a simple mathematical model to calculate and explain the possibility of drug migration in soil systems using the example of diffusion in agar gel in the presence of humic substances as the main component of organic matter in soil. In the present bachelor thesis, simulations of sulfapyridine diffusion in porous media, influenced by chemical side reactions of different series, were carried out. For these calculations COMSOL Multiphysics software and the corresponding packages "Chemistry" and "Transport of diluted species in porous media" were used, allowing simulations of real processes. The modelling results showed that the addition of reactive components to the hydrogel have an effect on the migration of sulfapyridine due to the interactions taking place during the diffusion. Reactions of different orders, including back reactions, were added successively to the simulations in inert media. The results obtained showed that the probable sum interaction mechanism has less influence on migration than the interaction of other mechanisms.
Interactions of pharmaceuticals with humic substances in model hydrogels
Fleischhackerová, Claudia ; Krouská, Jitka (referee) ; Klučáková, Martina (advisor)
This bachelor's thesis is focused on the study of drug diffusion in humic acid hydrogels. The instantaneous surface source diffusion method was used for this study. This method was based on the observation of emerging diffusion profiles of drugs which diffused in the humic gel at certain time intervals. Then, this method was used to determine the diffusion coefficients of the drugs used in the gels. The main aim of the experimental part was to study the influence of the interaction of drugs with humic acids that diffused through the humic gel. Two drugs were used as a diffusing medium, i.e. ibuprofen and tetracycline. They are pharmaceuticals, the consumption has been increasing in humans and animals in recent years, that's why they are often detected in the environment. The concentration profile of these drugs in humic acid hydrogels was determined by UV–VIS spectrometry.
Effect of changing ionic strength on the properties of catanionic vesicles from HTMA-DS
Filipová, Lenka ; Klučáková, Martina (referee) ; Mravec, Filip (advisor)
This diploma thesis is focused on evaluating the influence of ionic strength on catanionic vesicules made of ion pair amphiphile (IPA) in the form of HTMA-DS (hexadecyltrimethylammonium-dodecyl sulphate). Catanionic vesicles were stabilized by the addition of cationic surfactant dioctadecyldimethylammonium chloride (DODAC) and cholesterol. The ionic strength was attained by adding CaCl2 and Na2SO4 salts in the concentrations 0–300 mM. The changes influenced by ionic strength were studied by dynamic and electrophoretic light scattering (DLS and ELS), fluorescence anisotropy, generalized polarization (GP), pH measurement, and visual observation. During this experiment, the temperature was set both constant and altering in time. The measurement was performed shortly after adding salts to the catanionic vesicles and in-time measurement was performed as well. This thesis follows a bachelor thesis, where the influence of NaCl on the same type of catanionic vesicles in the same range of ionic strength was studied. The CaCl2 and Na2SO4 influences were then compared to the NaCl according to Hofmeister series. By the DLS and ELS method it was found that the size of vesicles with added CaCl2 and Na2SO4 was decreasing at first and then increasing whereas the -potential was exponentially decreasing with increasing ionic strength. The vesicle size, when the ionic strength was applied, was increasing in time while -potential was almost constant in time. The addition of both salts caused slight dehydration of the external part of the membrane which was examined by the fluorescent probe Laurdan (6-dodecanoyl-2-dimethylamino-naphthalene) and generalized polarization. By fluorescence anisotropy with the probe DPH (1,6-diphenyl-1,3,5-hexatriene), it was detected that both salts caused an increase of the fluidity of an inner part of a membrane. By both of the fluorescent techniques, it was confirmed that the increase in temperature caused a phase transition of the membrane from the solid ordered through the liquid ordered phase to the liquid disordered phase. The pH values also did not show any change with the addition of salts. When comparing the salts’ influence (CaCl2 and Na2SO4 versus NaCl) on catanionic vesicles it was found that in most cases NaCl influenced the observed properties the most. The addition of NaCl caused the largest increase in vesicle size, highest -potential values, initial dehydration of the external part of the membrane, and increased fluidity of the inner part of the membrane at I > 15 mM. These results are in agreement with the Hofmeister series. Based on the visual observation, the samples with ionic strength of more than 150 mM for CaCl2 and 75 mM for Na2SO4 were said to be unstable. This fact is in agreement with the result of ELS. The rest of the samples did not show any visual changes in time (28 days). Additionally, the influence of PBS buffer on catanionic vesicles at the same ionic strength values was studied. PBS buffer simulates the ionic environment of living organisms. Its' influence was characterized by the same methods under the same conditions as mentioned above. The effect of PBS on catanionic vesicles displayed almost the same behaviour in the observed properties. During this experiment, it was also found that the PBS influence on the studied properties was more significant than the influence of CaCl2, Na2SO4, and NaCl salts. Influence of PBS was most similar to the effect of NaCl on catanionic vesicles.
Interactions of pharmaceuticals with fulvic acids – calorimetric study
Papko, Nadezhda ; Sedláček, Petr (referee) ; Klučáková, Martina (advisor)
Tato diplomová práce se zaměřuje na studium interakcí mezi půdní organickou hmotou a vybranými léky pomocí izotermické titrační kalorimetrie. V rámci experimentu byly použity tři fulvinové kyseliny a léky: ibuprofen, diclofenac a sulfapyridine. Vybrané léky a fulvinové kyseliny byly rozpouštěné v roztocích NaCl a MgCl2, jelikož kovové ionty jsou přítomny v organickém materiálu půdy. Mobilita léčiv závisí na sorpci, což je interakce mezi léčivy a půdními částicemi. Faktory ovlivňující sorpční chování zahrnují vlastnosti léčiv, půdy a enviromentální podmínky. Během bakalářské práce podražilo optimalizovat metodu ITC pro daný studiu, což usnadnilo experimentální práce a zlepšilo vyhodnocení dat. Pomocí metody byli stanovené tepelné efekty (naměřené a porovnané) interakcí mezi fulvinovými kyselinami a léky.
Humic substances as modifiers of the transdermal absorption of active phasrmaceutical ingredients
Blahuš, Petr ; Klučáková, Martina (referee) ; Sedláček, Petr (advisor)
This thesis deals with the influence of humic substances on the transdermal penetration of the analgesic drug ibuprofen. Analgesics in the form of oral administration have major side effects. Thanks to topical preparations, side effects could be reduced and also bring a number of other benefits. The problem in the development of a transdermal form of the drug is the very effective barrier capacity of the human skin. Therefore, a lot of research is focused on the search for various accelerators that can improve its properties due to interaction with the drug. In the future, such substances could also include humic acids, which have a long tradition of use in a number of therapeutic approaches, and recently examples of their use in human medicine are increasingly appearing. The research was focused on the diffusive transport of sodium ibuprofen and its acidic counterpart. Franz diffusion cells were used to simulate the real environment, and skin isolated from pig ears was used as a membrane. Using UV-VIS spectrophotometry and HPLC, the samples were analyzed. Several values were calculated from the measured data, such as the effective diffusion coefficient, which were then compared and statistically checked. The result of this thesis is data that show the positive effect of humic substances on the transport of drugs through the skin membrane.
Transport of phamaceuticals in reactive hydrogels
Kotradyová, Viktória ; Kalina, Michal (referee) ; Klučáková, Martina (advisor)
The bachelor thesis focuses on a problem associated with diffusion processes of antibiotics in agarose hydrogels enriched with humic acids. The soil model system simulates the transport of these pollutants and demonstrates the ability of the humic acids to bind and retain these substances, thereby preventing their subsequent contamination at unintentional places. The theoretical section encompasses an overview of the occurrence of pharmaceuticals in soil and water systems; it also provides information about their behaviour, effects, degradation, and potential outcomes in nature. It further clarifies basic knowledge of soil components, in particular humic acids. Furthermore, the mechanism behind the diffusion processes is explicated. Within the experimental part, the diffusion of the sulfomethoxazole and sulfapyridine in two types of agarose hydrogels was examined. Firstly, the pure agarose hydrogel was used and secondly, the addition of the active agent in the form of humic acids was performed. The method of diffusion from continuous source was utilized, followed by measuring through UV-VIS spectrometry for 21 days. The study aimed to compare the results and to establish the diffusion coefficients of the pharmaceuticals in both types of hydrogels.
Transport of pharmaceuticals in soil systems
Janebová, Denisa ; Enev, Vojtěch (referee) ; Klučáková, Martina (advisor)
Drugs have a negative effect on nature. If they do not degrade in wastewater treatment plants, they can contaminate lakes, rivers and even drinking water. However, the soil contains soil organic matter, which has chelating properties and can prevent the migration of the drug. The aim of this bachelor thesis was to map the transport of the selected drug in the soil column and try to determine its diffusivity. Sulfapyridine was chosen for transport. Sulfapyridine belongs to a group of sulfonamide antibiotics that are often detected in the environment. It is mainly used in veterinary medicine to treat various infections. The partial goal was to describe the basic properties of the soil depending on the depth of the soil layer. The drug concentration profile in the soil column was determined by UVVIS spectrometry in soil extracts. The following reagents were used for leaching: distilled water, as a pure solvent without the presence of other substances, tap water as a model reagent replacing the soil solution and magnesium chloride solution, which is used for soil extracts of freely moving and ionically bound substances in the soil.
Hyaluronic gels for control release of active substances
Hekrlová, Veronika ; Smilek, Jiří (referee) ; Klučáková, Martina (advisor)
This diploma thesis is focused on the development of materials based on oxidized hyaluronic acid derivative (HA-Ox) crosslinked using bifunctional alkoxyamine POA. Hydrogels have been studied as potential matrices for the controlled release of biological drugs. For this purpose, hydrogels containing bovine serum albumin (BSA) as model of the active substances were prepared. The properties of the hydrogels were affected by the concentration of the derivative (10 mg / ml, 20 mg / ml and 30 mg / ml). In the first part of the work, the viscoelastic properties, swelling and dry matter content of the prepared hydrogels were evaluated. The dry matter of the starting hyaluronan derivative and the weight of the polymer network in the hydrogels were determined gravimetrically and by TGA (in all cases about 80% w/w). The difference in weight of the polymer contained in the hydrogels before and after swelling showed that the non-crosslinked sol leaches out of the hydrogel during swelling (about 10-20% w/w). Due to this phenomenon, hydrogels with a concentration of 10 mg / ml are depleted of hydrogels, while their more concentrated analogues swell even after the sol has washed off. The sizes of elastic moduli needed to calculate the mesh of the polymer network were determined using rheological measurements (amplitude and frequency test). The mesh size of the polymer network itself is calculated using two commonly used theories: Equilibrium SwellingTheory (EST) and Rubber Elasticity Theory (RET). The mesh size of BSA-free gels with a derivative concentration of 10 to 30 mg/ml was determined according to EST to 347 ± 29 nm, 319 ± 15 nm, 295 ± 6 nm and according to RET345 ± 30 nm, 308 ± 14 nm, 268 ± 5 nm. For hydrogels with BSA, the mesh sizes of the polymer network were determined according to EST 373 ± 34 nm, 307 ± 11 nm, 281 ± 7 nm and according to RET 372 ± 32 nm, 297 ± 11 nm, 258 ± 6 nm. The mesh size of the polymer network decreases with higher derivative concentration. In the second part of the work, the release of the model active substance BSA was monitored spectrophotometrically using fluorescent labeling. Using the Korsmeyer-Peppas model, it was found that diffusion release is the primary mechanism.
Study of hydration of biocolloids
Hývnarová, Lucie ; Sedláček, Petr (referee) ; Klučáková, Martina (advisor)
The subject of this master’s thesis was to examine the hydration properties of selected biocolloids. Specifically, humic substances (fulvic and humic acids), hyaluronic acids in three molecular weights, dextran and chitosan were investigated. Hydration properties of selected biocolloid substances were studied by various methods. The influence of water content during the dissolution of substances and the different time for which water acted on biocolloids were studied. Differential scanning calorimetry DSC measurements resulted in enthalpies and crystallization and melting points. Heat fluxes resulted in the use of perfusion calorimetry. TGA thermogravimetric analysis was used to determine the moisture content of the bioolloids used, after measuring the perfusion calorimeter.

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