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Formulation of vancomycin loaded PLGA nanoparticles for local treatment of musculoskeletal infections II.
Ptáčková, Karolína ; Šnejdrová, Eva (advisor) ; Zbytovská, Jarmila (referee)
Charles University Faculty of Pharmacy in Hradec Králové Department of Pharmaceutical Technology Author: Karolína Ptáčková Title of thesis: Formulation of vancomycin loaded PLGA nanoparticles for local treatment of musculoskeletal infections II. Supervisor: PharmDr. Eva Šnejdrová, Ph.D. Consultant: Mgr. Vladislav Frolov The aim of the work was to formulate vancomycin hydrochloride (Van-HCl) loaded PLGA nanoparticles (NPs) using a double emulsion method for the local treatment of musculoskeletal infections. During preparation, selected critical formulation factors were modified and their influence on the characteristics of nanoparticles was studied. The size of the NPs determined by the DLS method ranged from 200 to 800 nm, the PDI was lower than 0.2 in most batches. The encapsulation efficiency (EE) determined by the direct method ranged from 2 % to 9 %. Glycerol monostearate at a concentration of 15 mg/ml proved to be a suitable primary emulsion stabilizer. The optimal concentration of PVA for stabilizing the nanosuspension was 30 mg/ml. The size of the NPs was influenced by the intensity of homogenization and the concentration of PVA. The concentration of Van-HCl, the organic solvent used and the intensity of homogenization led to an increase in EE. The DSC method confirmed that Van-HCl remains...
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Formulation of vancomycin loaded PLGA nanoparticles for local treatment of musculoskeletal infections I.
Petrášová, Ivana ; Šnejdrová, Eva (advisor) ; Smékalová, Monika (referee)
Charles University Faculty of Pharmacy in Hradec Kralove Department of Pharmaceutical Technology Author: Ivana Petrášová Title of thesis: Formulation of PLGA nanoparticles with vancomycin for local treatment of musculoskeletal infections I Supervisor: PharmDr. Eva Šnejdrová, Ph.D. The treatment of musculoskeletal infections requires the presence of high antibiotics concentration at the infection site. However, high doses of orally administered drugs cause the risk of increased systemic toxicity and serious adverse effects. Targeted drug delivery, currently one of the main areas of pharmaceutical research, represents a suitable option of a treatment without excessive burden on the organism. This diploma thesis focuses on the formulation of a therapeutic system for the local treatment of musculoskeletal infections in the form of polymer nanoparticles containing the antibiotic vancomycin. Due to the need of incorporation of a hydrophilic antimicrobial substance into them, the suspension-emulsion method of their preparation was used. Different concentrations of polyvinyl alcohol stabilizer and tripentaerythritol branched hydrophobic polymer poly(D,L- lactide-co-glycolide) were used for the preparation. Within the study the size of nanoparticles, polydispersity, zeta potential, encapsulation efficiency...
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Post-polymerization modification of block copolymers as a tool for preparation of new drug delivery nanosystems
Marková, Pavlína ; Uchman, Mariusz Marcin (advisor) ; Košovan, Peter (referee)
Amphiphilic block copolymers self-assemble into clinically efficacious nanostructures, whose size, stability, and surface chemistry can be easily adjusted for each purpose. This versatility has prompted the vast scope of their biomedical applications, especially in the field of drug delivery. In particular, polyester-based nanoparticles have been used in gene, nucleic acid, therapeutic protein and drug delivery for their in vivo biocompatibility and biodegradability. However, most studies have only focused on amphiphilic copolymers with either short hydrophobic segments, no modification or a single preparation pathway. This diploma thesis focuses on the synthesis of poly(ethylene oxide)-b-poly(caprolactone) copolymers containing propargyl groups using two parallel approaches, namely a copolymerization with a modified monomer and a post-polymerization modification. A subsequent thiol-yne click reaction with 1-thioglycerol yielded copolymers with vicinal diols, which can reversibly bind to benzoxaborole- and boronic acid-derived compounds. Both synthetic pathways were evaluated based on macromolecular characteristics afforded by nuclear magnetic resonance spectroscopy and by size exclusion chromatography. Furthermore, we characterized the self-assembled nanoparticles by static and dynamic light...
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Nanofibrous scaffolds in controlled delivery of autologous growth factors
Buzgo, Matej ; Amler, Evžen (advisor) ; Gášková, Dana (referee)
Platelet preparations are a source of various autologous growth factors and have numerous applications in tissues engineering. The aim of this work was to development electrospun nanofiber scaffolds with platelet preparations. Scaffolds based on the adhesion of platelets on nanofiber meshes were developed. The scaffolds were able to enhance chondrocyte proliferation in vitro. The main disadvantage of this system is the burst release of growth factors immediately after adhesion. To overcome this, we developed coaxially electrospun scaffolds with incorporated alpha granules. Alpha granules are novel platelet preparations with high amounts of growth factors. This system was able to stimulate chondrocyte proliferation and maintain TGF- 1 concentrations for 7 days. Additionally, a novel drug delivery system with coaxially incorporated liposomes was developed. Liposomes incorporated into nanofibers remain intact and can be used for the delivery of various molecules. The ability to maintain HRP activity was compared to systems based on coaxial electrospinning with liposomes, coaxial electrospinning without liposomes and blend electrospinning. When compared to other systems, coaxial electrospinning with liposomes preserves enzyme activity twice as long. These results clearly indicate the potential of...
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The preparation and characterization of polymeric, enzymatically cleavable carriers for cancerostatic drugs
Zelený, Jan ; Etrych, Tomáš (advisor) ; Ječmen, Tomáš (referee)
As the development of cancerostatic drugs progresses it is becoming necessary to contemplate the question of how to deliver these drugs, which themselves tend to exhibit carcinogenic properties, effectively and accurately to the affected tissues and thus to circumvent their destructive effects upon the healthy parts of the organism. One approach to delivering drugs selectively to cancerous tissues is to make use of some of the specific properties which these tissues tend to possess, one of which being the so-called enhanced permeability and retention effect (EPR effect). This effect, which will be further discussed within this thesis, allows for macromolecules that are too massive to pass from the bloodstream into healthy tissue, to exit the blood vessels of cancerous tissue and to accumulate there. Therefore, a drug molecule can specifically enter cancerous tissue along with a suitable macromolecule, to which it is conveniently attached. If, moreover, the given drug is connected to the carrier molecule via an enzymatically cleavable spacer, it is possible to make use of lysosomal proteases (such as cathepsin B, which is overexpressed in some cancer cells) in order to attain its detachment from the carrier molecule and its subsequent activation. This bachelor thesis focuses on describing the...
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Synthesis of novel types of acyclic nucleoside phosphonates and preparation of prodrugs and drug delivery systems
Kalčic, Filip ; Janeba, Zlatko (advisor) ; Míšek, Jiří (referee) ; Krečmerová, Marcela (referee)
First part of this thesis was focused on the previously overlooked field of C1'-branched acyclic nucleoside phosphonates (ANPs). Five diverse synthetic approaches were developed/optimized affording key 6-chloropurine intermediates bearing N9 -phosphonomethoxyethyl (PME) branched at C1' position in 2-4 steps. It was demonstrated that these intermediates can be further vastly diversified into ANPs bearing both natural and unnatural nucleobases. Single enantiomers as well as racemates of final C1'-branched ANPs (overall 48 final compounds) were prepared and selected compounds were evaluated with respect to their biological properties. The aforementioned ANPs showed no antiviral potency against studied viruses and only weak to moderate cytostatic activity. Adenine C1'-branched ANPs proved to be the most potent currently known inhibitors of Trypanosoma brucei adenine phosphoribosyl transferase (TbrAPRT), an enzyme involved in purine salvage pathway (PSP) of T. brucei. Further biological evaluation of prepared compounds is in progress. Second part of this thesis was focused on development of novel prodrug moieties with higher selectivity index (i.e. toxicity/potency ratio - SI) based on so-called ProTide prodrugs where phenol (present in ProTides) was replaced by tyrosine derivatives. Tenofovir was...
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Polymer carriers for nuclear medicine
Sedláček, Ondřej
In the thesis, we developed and studied a novel polymer delivery system for the DNA-intercalator bearing radioisotope iodine-125. Auger electrons emitting radioisotopes (such as iodine-125 or indium-111) are a potentially effective cancer treatment. Their use as an effective cancer therapy requires that they will be transported within close proximity of DNA, where they induce double-strand breaks leading to the cell death. This type of therapy may be even more beneficial when associated with drug delivery systems. The DNA intercalators proved to be effective carriers for the delivery of Auger electron emitters into DNA. Therefore, the new radioiodinated DNA-intercalating ellipticinium derivatives were synthesized and characterized. These compounds were linked to N-(2-hydroxypropyl) methacrylamide copolymer with narrow molecular weight distribution via acid-sensitive hydrazone linker. The structure of the linker plays a crucial role in the biological effectivity of the delivery system, so it was optimized to be stable at pH 7.4 (representing the pH of blood plasma), whereas in slightly acidic pH in endosomes after the cell internalization, the radioiodine-containing biologically active intercalator is rapidly released from its polymer carrier. The intercalating ability of the active compound was...
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Polymer carriers for nuclear medicine
Sedláček, Ondřej
In the thesis, we developed and studied a novel polymer delivery system for the DNA-intercalator bearing radioisotope iodine-125. Auger electrons emitting radioisotopes (such as iodine-125 or indium-111) are a potentially effective cancer treatment. Their use as an effective cancer therapy requires that they will be transported within close proximity of DNA, where they induce double-strand breaks leading to the cell death. This type of therapy may be even more beneficial when associated with drug delivery systems. The DNA intercalators proved to be effective carriers for the delivery of Auger electron emitters into DNA. Therefore, the new radioiodinated DNA-intercalating ellipticinium derivatives were synthesized and characterized. These compounds were linked to N-(2-hydroxypropyl) methacrylamide copolymer with narrow molecular weight distribution via acid-sensitive hydrazone linker. The structure of the linker plays a crucial role in the biological effectivity of the delivery system, so it was optimized to be stable at pH 7.4 (representing the pH of blood plasma), whereas in slightly acidic pH in endosomes after the cell internalization, the radioiodine-containing biologically active intercalator is rapidly released from its polymer carrier. The intercalating ability of the active compound was...
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The preparation and characterization of polymeric, enzymatically cleavable carriers for cancerostatic drugs
Zelený, Jan ; Etrych, Tomáš (advisor) ; Ječmen, Tomáš (referee)
As the development of cancerostatic drugs progresses it is becoming necessary to contemplate the question of how to deliver these drugs, which themselves tend to exhibit carcinogenic properties, effectively and accurately to the affected tissues and thus to circumvent their destructive effects upon the healthy parts of the organism. One approach to delivering drugs selectively to cancerous tissues is to make use of some of the specific properties which these tissues tend to possess, one of which being the so-called enhanced permeability and retention effect (EPR effect). This effect, which will be further discussed within this thesis, allows for macromolecules that are too massive to pass from the bloodstream into healthy tissue, to exit the blood vessels of cancerous tissue and to accumulate there. Therefore, a drug molecule can specifically enter cancerous tissue along with a suitable macromolecule, to which it is conveniently attached. If, moreover, the given drug is connected to the carrier molecule via an enzymatically cleavable spacer, it is possible to make use of lysosomal proteases (such as cathepsin B, which is overexpressed in some cancer cells) in order to attain its detachment from the carrier molecule and its subsequent activation. This bachelor thesis focuses on describing the...
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Aliphatic polyester-based nanoparticles as drug delivery systems
Jäger, Alessandro ; Štěpánek, Petr (advisor) ; Sedláček, Jan (referee) ; Sikora, Antonín (referee)
Nanoparticles from biodegradable polymers are considered one of the most promising systems for biomedical application as drug delivery systems. Therefore, the synthesis and characterization of a new aliphatic biodegradable copolyester named PBS/PBDL (poly(butylene succinate-co- butylene dilinoleate)) intended to the application as drug delivery system is reported in the thesis. Surfactant-free biodegradable and narrowly distributed, nanosized spherical particles (RH < 60 nm) have been produced from the biodegradable material by applying a single-step nanoprecipitation protocol. The size of the generated polymer nanoparticles (PNPs) could be controlled by adjusting the polymer concentration, the choice of organic solvent, mixing different organic solvents or by changing temperature and ionic strength. By optimizing such parameters sub-100 nm uniform PNPs can be produced through this methodology including the advantage and ability to scale-up production. The nanoparticles structure was characterized in detail by employing a variety of scattering techniques and transmission electron microscopy (TEM). Combined static light scattering (SLS) and dynamic light scattering (DLS) measurements suggested that the nanoparticles comprise a porous core conferring them a non-compact characteristic. Their porosity...
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