|
|
Surface active compounds and evaluation of its properties
Lanzendorfová, Jana ; Holas, Ondřej (advisor) ; Paraskevopoulos, Georgios (referee)
Charles University, Faculty of Pharmacy in Hradec Králové Department of Pharmaceutical Technology Mentor: PharmDr. Ondřej Holas, PhD. Consultant: PharmDr. Jan Marek, PhD. Student: Jana Heinrichová Title of Thesis: Surface active compounds and evaluation of its properties The theoretical part of the thesis is focused on the properties of surfactants, their distribution, and their use. In this part, micelles, critical micelle concentration, methods of its determination and factors influencing it are also characterized. In the experimental part, the critical micelle concentration (CMC) of two homologous series of quaternary ammonium salts (benzalkonium chlorides and benzoxonium chlorides) was evaluated by a conductometric method. Several parameters (side chain length, temperature, pH) and their influence on the critical micelle concentration value were monitored. Furthermore, the critical micelle concentration of these substances was measured using a Wilhelmy plate to compare the two methods. The relationship between decreasing critical micelle concentration value and increasing alkyl chain length was verified. At the same time, the dependence of CMC on temperature and pH change was verified. Finally, the conductometric method of CMC determination was compared with the Wilhelmy plate method, and their...
|
|
|
Polymeric nanoparticles for poorly water soluble drugs delivery
Nekolová, Martina ; Holas, Ondřej (advisor) ; Smékalová, Monika (referee)
Charles University in Prague, Faculty of Pharmacy in Hradec Králové Department of Pharmaceutical Technology Mentor: PharmDr. Ondřej Holas, Ph.D. Student: Martina Nekolová Title of thesis: Polymeric nanoparticles for poorly water-soluble drugs delivery Polymeric nanoparticles represent a modern drug form. One of the main advantages is influencing the pharmacokinetic properties of the administered substance - e.g. increasing solubility in water. They enable the targeted delivery of the drug to the affected tissue and this way minimize adverse effects. This could be of great benefit to the therapy of cancer or inflammatory diseases. Both the target tissue and the nanoparticles must have some specific properties. For particles, it is, for example, size and surface charge. The aim of this work was to prepare nanoparticles with a substance poorly soluble in water, represented by curcumin. The particles were prepared by the nanoprecipitation method with different types of poly(lactic-co-glycolic acid) (PLGA) copolymer. A 50:50 linear PLGA polymer and a branched PLGA A2 polymer were used. The prepared nanoparticles were compared on several parameters - particle size and polydispersity, encapsulation efficiency (EE), drug-loading capacity (DLC) and dissolution profile. PLGA 50:50 was found to provide...
|
|
|
Dissolution study of PLGA nanoparticles
Budigová, Aneta ; Smékalová, Monika (advisor) ; Holas, Ondřej (referee)
Charles University, Faculty of Pharmacy in Hradec Králové Department of Pharmaceutical Technology Consultant: Mgr. Monika Smékalová Ph.D. Student: Aneta Budigová Title od thesis: Dissolution study of PLGA nanoparticles PLGA nanoparticles are used as nanoparticle carrier systems for targeted distribution and controlled release of drugs. The aim of this diploma thesis was to prepare PLGA nanoparticles with encapsulated fluorescein and dexamethasone acetate and subsequently dissolve them in various media. Fluorescein as a model substance was chosen because of its low solubility in water, which is close to that of dexamethasone acetate. Nanoparticles were prepared by the nanoprecipitation method. The following dissolution media were chosen for fluorescein dissolution: 0.01M PBS, saline, acetate buffer, and artificial lysosomal fluid (ALF). Dissolution of PLGA nanoparticles with dexamethasone acetate was performed in 0.01 M PBS. The nanoparticles were also evaluated for size, PDI, zeta potential and encapsulation efficiency. The willingness of fluorescein to release from PLGA nanoparticles decreased in the order: acetate buffer saline, 0.01M PBS and ALF. Lowering the pH of the dissolution medium from 7.4 (PBS, saline) to 5.5 (acetate buffer) resulted in the release of approximately twice as much...
|
|
|
Preparation and evaluation of nanoparticles for targeted treatment of inflammatory diseases
Wurzel, Natalie ; Holas, Ondřej (advisor) ; Smékalová, Monika (referee)
Charles University, Faculty of Pharmacy in Hradci Králové Department of Pharmaceutical Technology Supervisor: PharmDr. Ondřej Holas, PhD Consultant: Mgr. Barbora Boltnarová Student: Natalie Wurzel Title of Thesis: Preparation and evaluation of nanoparticles for targeted treatment of inflammatory diseases Nanoparticles are used in the health sciences for, among other things, targeted drug delivery. This is used for the therapy of cancer and chronic inflammatory diseases. The aim of this diploma thesis was to prepare nanoparticles suitable for targeted treatment of inflammatory diseases. The task was to determine the ideal concentration of the active substance, which would ensure high encapsulation efficiency and drug loading. The difference between nanoparticles prepared from PLGA 5/5E and PLGA 7/3A was also investigated. Nanoparticles were prepared by the nanoprecipitation method. The matrix of the nanoparticles was composed of PLGA with different ratios of lactic acid and glycolic acid. Acetone was used as the organic solvent. The encapsulated active substance was the anti-inflammatory dexamethasone acetate. The aqueous phase was consisted of a 0.1% aqueous solution of Pluronic F-127. The evaluated parameters of the resulting nanoparticles included size, polydispersity index, zeta potential,...
|
|
|
Study of the effect of biomolecules on the solubility of poorly soluble drugs
Kheirabadi, Fatemeh ; Holas, Ondřej (advisor) ; Vraníková, Barbora (referee)
Charles University, Faculty of Pharmacy in Hradec Králové Department of Pharmaceutical Technology Supervisor: Dr. Ondrej Holas, Ph.D. Consultant: prof. Anette Müllertz, Ph.D. Student: Fatemeh Kheirabadi Title of thesis: Effects of Proteins on Apparent Drug solubility in Fasted State Stimulated Colonic Fluids This thesis investigates the influence of proteins on the apparent solubility of drugs in fasted state stimulated colonic fluids. The investigation was conducted on a selection of compounds with varying physicochemical and plasma protein binding properties. Precisely, three different compounds named as Nilotinib, Carvedilol and Ritonavir were analyzed for their apparent solubility in three distinct protein sources: bovine serum albumin, mucin from dehydrated porcine gastric mucin type II, and collected porcine intestinal mucus. Accurate reversed-phase high-performance liquid chromatography was developed and employed as the analytical method to determine the concentration of the apparent drug solubility of the investigated compounds. The research on the solubility of poorly soluble compounds in simulated colonic fluids has been restricted. Additionally, factors such as the impact of proteins remains unexplored in biorelevant media, which could be critical for enhancing our understanding of drug...
|
|
|
Polymeric nanoparticles: platform for poorly water soluble drugs delivery
Roztočilová, Adéla ; Holas, Ondřej (advisor) ; Svačinová, Petra (referee)
Charles University in Prague, Faculty of Pharmacy in Hradec Králové Department of Pharmaceutical Technology Mentor: PharmDr. Ondřej Holas, Ph.D. Student: Adéla Roztočilová Title of thesis: Polymeric nanoparticles as a platform for delivery of poorly water-soluble drugs Polymer nanoparticles can be used as drug carriers due to their beneficial properties. One of the advantages of polymeric nanoparticles is, for example, to increase the solubility of drugs in water. They have great potential in the therapy of inflammatory diseases such as Crohn's disease or in shifting cancer pharmacotherapy. The main objective of this thesis was to prepare polymeric nanoparticles with encapsulated curcumin as model active ingredient. Four types of poly(lactic-co-glycolic acid) (PLGA) copolymer were used to prepare the nanoparticles. Nanoprecipitation and emulsion evaporation methods were employed. The parameters evaluated were encapsulation efficiency, drug loading, particle size and polydispersity. Both the water phase, where two different surfactants were employed, and the organic phase were varied during the experiment. The experimental part also used a dissociation method where two types of PLGA copolymer were compared and during the dissociation, samples were taken at predetermined times to determine the total...
|
|
|
Polymeric nanoparticles for poorly water soluble drugs delivery
Nekolová, Martina ; Holas, Ondřej (advisor) ; Smékalová, Monika (referee)
Charles University in Prague, Faculty of Pharmacy in Hradec Králové Department of Pharmaceutical Technology Mentor: PharmDr. Ondřej Holas, Ph.D. Student: Martina Nekolová Title of thesis: Polymeric nanoparticles for poorly water-soluble drugs delivery Polymeric nanoparticles represent a modern drug form. One of the main advantages is influencing the pharmacokinetic properties of the administered substance - e.g. increasing solubility in water. They enable the targeted delivery of the drug to the affected tissue and this way minimize adverse effects. This could be of great benefit to the therapy of cancer or inflammatory diseases. Both the target tissue and the nanoparticles must have some specific properties. For particles, it is, for example, size and surface charge. The aim of this work was to prepare nanoparticles with a substance poorly soluble in water, represented by curcumin. The particles were prepared by the nanoprecipitation method with different types of poly(lactic-co-glycolic acid) (PLGA) copolymer. A 50:50 linear PLGA polymer and a branched PLGA A2 polymer were used. The prepared nanoparticles were compared on several parameters - particle size and polydispersity, encapsulation efficiency (EE), drug-loading capacity (DLC) and dissolution profile. PLGA 50:50 was found to provide...
|
|
|
Surface active compounds and evaluation of its properties
Heinrichová, Jana ; Holas, Ondřej (advisor) ; Paraskevopoulos, Georgios (referee)
Charles University, Faculty of Pharmacy in Hradec Králové Department of Pharmaceutical Technology Mentor: PharmDr. Ondřej Holas, PhD. Consultant: PharmDr. Jan Marek, PhD. Student: Jana Heinrichová Title of Thesis: Surface active compounds and evaluation of its properties The theoretical part of the thesis is focused on the properties of surfactants, their distribution, and their use. In this part, micelles, critical micelle concentration, methods of its determination and factors influencing it are also characterized. In the experimental part, the critical micelle concentration (CMC) of two homologous series of quaternary ammonium salts (benzalkonium chlorides and benzoxonium chlorides) was evaluated by a conductometric method. Several parameters (side chain length, temperature, pH) and their influence on the critical micelle concentration value were monitored. Furthermore, the critical micelle concentration of these substances was measured using a Wilhelmy plate to compare the two methods. The relationship between decreasing critical micelle concentration value and increasing alkyl chain length was verified. At the same time, the dependence of CMC on temperature and pH change was verified. Finally, the conductometric method of CMC determination was compared with the Wilhelmy plate method, and their...
|
|
|
Development of material for agar-based ultrasound brain phantom
Řehořková, Petra ; Smékalová, Monika (advisor) ; Holas, Ondřej (referee)
Charles University, Faculty of Pharmacy in Hradec Králové Department of: Pharmaceutical technology Mentor: Mgr. Monika Smékalová, Ph.D. Consultant: MUDr. Michael Bartoš Student: Petra Řehořková Title of Thesis: Development of material for agar-based ultrasound brain phantom This thesis is concerned with the development of a material for an agar-based ultrasound phantom that would provide skill acquisition and experience in a manner approximating real surgery. The aim is to formulate and optimize the agar hydrogel preparation procedure, evaluate its acoustic properties and water loss during storage. A dependence was found between the amount of water evaporated during storage (4 weeks at 37 řC) and the glycerol content, which slows down the water loss from the samples in direct proportion. Based on the results, an agar gel (AG) formulation with 1% agar and 60% glycerol was selected for the acoustic properties measurements. During this experiment the microbial stability of AG was confirmed. The results of acoustic parameters measurements were evaluated, namely, speed of the ultrasound, attenuation coefficient and echogenicity of the samples as a function of content of scattering particles Al2O3 and SiC. It was shown that each type of particles affects grayscale value and attenuation coefficient in a...
|
|
|
Cholinesterases inhibited by novichok agents - in silico study of reactivation possibilities
Večeřa, Zbyněk ; Roh, Jaroslav (advisor) ; Holas, Ondřej (referee)
Title: Cholinesterases inhibited by novichok agents - in silico study of reacti- vation possibilities Author: Zbyněk Večeřa Department: Department of Organic and Bioorganic Chemistry Supervisor: doc. PharmDr. Jaroslav Roh, Ph.D. Advisor: PharmDr. Mgr. Tomáš Kučera, Ph.D. Abstract: Substances known as Novichok agents are banned chemical warfare agents, which were developed in Soviet Union between the 1970s and the 1980s. They were brought to the public attention very recently - they were used to po- ison a double agent named Skripal in 2018 and again in 2020 to poison Russian politician Navalny. It is the 4th generation of nerve agents which cause cholinergic syndrome by irreversible inhibition of acetylcholinesterase (AChE), manifesting symptoms such as depression of bronchial tubes, cramps or even paralysis of re- spiratory muscles and depression of the respiratory control centre in the brain. Victim then dies of asphyxiation unless antidotes are administered as soon as possible. Treatment of nerve agents induced poisoning is based on reactivating AChE by oxime compounds which bind themselves with the toxic substance by nucle- ophilic attack on electropositive point of the nerve agent, releasing acetylcholi- nesterase that can continue with function of acetylcholine hydrolysis. The task was to...
|
guest ::
