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1
Easley, Christina A. "Electrically-assisted enhancement of transdermal drug delivery using magainin peptides." Thesis, Georgia Institute of Technology, 2002. http://hdl.handle.net/1853/21419.
Повний текст джерела
2
SOLLAMI, DELEKTA SZYMON. "Hexosomes as Drug Delivery Vehicles for Antimicrobial Peptides." Thesis, KTH, Skolan för kemivetenskap (CHE), 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-172360.
Повний текст джерелаАнотація:
This master thesis project was carried out at SP Technical Research Institute of Sweden within the FORMAMP project which goal is to increase the efficiency and stability of antimicrobial peptides (AMPs) by exploring and developing a number of innovative formulation strategies for the drug delivery of those systems. In view of the growing problem of bacterial resistance to traditional antibiotics, AMPs represent one of the most promising alternatives as therapeutics against infectious diseases: besides having a fast and non-specific mechanism of action, they are less prone to bacterial resistance. In this project, the goal was to develop an efficient method for the formulation of hexagonal lyotropic phase nanodispersions (called hexosomes) as drug delivery vehicles for the AP114, DPK-060 and LL-37 AMPs. Then, these formulations were characterized through size measurements, zeta potential measurements, SAXS, cryo-TEM and UPLC and their stability was assessed. Lastly, the interaction of these systems with model bacterial membranes was tested through QCM-D and ellipsometry. The relevant samples were found to have a hexagonal structure with the lattice parameter being larger when peptide was loaded. The systems were observed to be sufficiently stable and the peptide loading efficiency was found to be higher than 90% in most cases. The hexosomes loaded with LL-37 were observed to preserve the effectiveness of the peptide when interacting with the model membrane through QCM-D.
3
Vellore, Janarthanan Mohanraj. "Formulation of chitosan-based nanoparticles for delivery of proteins and peptides." Thesis, Curtin University, 2003. http://hdl.handle.net/20.500.11937/1224.
Повний текст джерелаАнотація:
Delivery of complex molecules such as peptides, proteins, oligonucleotides and plasmids is an intensively studied subject, which has attracted considerable medical and pharmaceutical interest. Encapsulation of these molecules with biodegradable polymers represents one way of overcoming various problems associated with the conventional delivery of macromolecules, for example instability and short biological half-life. The use of carriers made of hydrophilic polysaccharides such as chitosan, has been pursued as a promising alternative for improving the transport of biologically active macromolecules across biological surfaces. The development of nanoparticles as a delivery system also has major advantages of achieving possible drug protection, controlled release and drug targeting by either a passive or an active means. The aim of this study was to develop a simple and effective method to formulate biodegradable nanoparticles for the delivery of a model protein-bovine serum albumin (BSA) and an angiogenesis inhibitor, arginine-rich hexapeptide (ARE peptide). Major factors which determine nanoparticle formation and loading of the protein and the peptide as well as the underlying mechanisms controlling their incorporation and release characteristics were investigated. The preparation technique, based on the complex coacervation process, is extremely mild and involves the mixture of two aqueous solutions (chitosan and dextran sulfate) at room temperature. The formation of nanoparticles is dependent on the concentrations of chitosan (CS) and dextran sulfate (DS); particles with size, of 257 to 494nm can be obtained with 0.1%w/v solutions of CS and DS. Zeta potential of nanoparicles can be modulated conveniently from -34.3mV to +52.7mV by varying the composition of the two ionic polymers.Both bovine BSA and the ARH peptide were successfully incorporated into CS-based nanoparticles, mainly via an electrostatic interaction, with entrapment efficiency up to 100% and 75.9% for the protein and peptide respectively. Incorporation of both the protein and peptide into nanoparticles resulted in an increase in size suggesting their close association with the nanoparticle matrix material. The difference in sign and magnitude of zeta potential of empty and macromolecules-loaded nanoparticles supports the hypothesis that protein and peptide association with nanoparticles can be modulated by their ionic interaction with the oppositely charged ionic polymer (DS) in the nanoparticles. The release of BSA from the nanoparticles was very slow in water compared to that in l0mM phosphate buffer pH 7.4; whereas, ARH peptide showed extremely low level of release in water at the low ratio of DS but at the high ratio of DS, its release was in biphasic fashion, with an initial burst effect followed by an almost constant but very slow release up to 7 days in both water and 1 OmM phosphate buffer (pH 7.4). It was found that, unlike ARH peptide, the percentage of BSA released was relatively slower for the nanoparticles with a high ratio of DS. It is speculated that this difference in the release behaviour of BSA and ARH peptide, could be due to the effect of molecular size of the compounds and their interaction with the polymer matrix of the nanoparticle. The results of this study suggest that these novel CS/DS nanoparticulate system, prepared by a very mild ionic crosslinking technique, have potential to be a suitable carrier for the entrapment and controlled release of peptides and proteins.
4
Abdulrazzaq, Fadi. "Aquasomes as a drug delivery system for proteins and peptides." Thesis, Aston University, 2016. http://publications.aston.ac.uk/30080/.
Повний текст джерелаАнотація:
Aquasomes are nanocarrier systems consist of three distinctive layers; an inner core, a polyhydroxy carbohydrate layer and an outer layer of an API (Kossovsky et al., 1991). Aquasomes have a unique structure and ability to carry active molecules through a non-covalent bounding and provide superior stability, especially for proteins and peptides (Masatoshi and Yongning, 1998; Kim and Kim, 2002; Khopade et al., 2002). Different core and coating materials were used to prepare aquasomes under different conditions to investigate the relationship between preparation conditions and loading efficiency. In terms of loading efficiency, hydroxyapatite aquasomes, with either lactose or trehalose as a coating material, had the highest BSA loading (40%-60%) when compared to DSPA aquasomes. While DCPA aquasomes, with either lactose or trehalose as a coating material, had the lowest BSA loading (8%-16%). To investigate the interaction of the three layers of aquasomes, Surface analysis, docking and MD simulations were performed. Surface analysis performed by Discovery Studio showed that HA and trehalose interact by hydrogen bonding with the later acting as a hydrogen acceptor, while BSA displayed almost complete SAS and that there are numerous targets for trehalose attachments (no specific active site). MD simulations of BSA performed by AMBER 12 showed a stable MD simulation of BSA for 5 ns. Total energy analysis of BSA on the two conditions performed (300K and 280K) support the experimental data of lower BSA loadings of aquasomes prepared at 400C compared to those manufactured at 250C (p < 0.05). This could be related to that BSA might have either started to denature/unfold or breaking up which eventually resulted in low BSA loadings obtained experimentally. The high loading efficiency highlights aquasomes as a promising carrier for the delivery of proteins and peptides. Following formulation Optimisation, two routes of delivery were investigated, pulmonary and oral routes. For pulmonary delivery of aquasomes, BSA-loaded aquasomes were successfully formulated as pMDI and DPI formulations. Both pMDI and DPI formulations were investigated to identify lung distribution of BSA-loaded aquasomes using NGI. In vitro release studies on the selected size fractions from NGI show a sustained release of BSA over a period of 6 hr. In order to complement the in vitro release data, cell culture studies were performed to demonstrate the controlled release effect of aquasomes with BEAS-2B cell lines. The release of salbutamol sulphate (model drug) from aquasomes post 2 hr started to slow gradually until it reached its highest difference at 6 hr (p<0.05) when compared to the control. For oral delivery of aquasomes, BSA-loaded aquasome tablets were successfully formulated with MCC as multifunctional excipient and talc as a lubricant. Various powder blends of varying aquasomes amounts (25, 37.5, 50, 62.5 and 75%) were prepared and compressed at increasing compression forces (0.5, 1, 2 and 3 tons). It was noticed that under high compression forces of 2 and 3 tons, BSA spreads out of BSA-loaded aquasomes as was presented with confocal microscopy images. Tablets compressed under 1 ton of compression force was therefore chosen for coating as it showed desirable tablet characteristics (hardness, disintegration etc.). Acrylic based coating was used to spray coat the tablets. The coated tablets were found to disintegrate in pH >5.5 and steadily release for 6 hr. Cell culture studies were conducted to demonstrate the controlled release effect of aquasomes using Caco-2 cell lines. The release of metronidazole (model drug) from aquasomes post 2 hr started to slow gradually until it reached its highest difference at 6 hr (p<0.05) when compared to the control.
5
Mitra, Deboleena. "Light Mediated Drug Delivery Using Photocaged Molecules and Photoswitchable Peptides." VCU Scholars Compass, 2014. http://scholarscompass.vcu.edu/etd/3618.
Повний текст джерелаАнотація:
There are many different types of targeted therapy for cancer treatment. The method of light mediated targeted therapy that we have developed uses photocaged molecules and photoswitchable peptides.
In photocaging, a biologically active molecule is made inactive by the attachment of a photocleavable blocking group. On exposure to UV radiation the photocleavable entity is removed and the biologically active molecule is released. Using this concept we have designed a prodrug that consists of a cell impermeable hydrophilic molecule attached to a photocaged doxorubicin. Upon irradiation with UV light the photosensitive group is removed and cytotoxic doxorubicin is released at the tumor site. This concept has been further modified by attaching receptor binding molecules to the photocaged entity to increase its specificity.
A peptide which consists of an azobenzene photoswitch has been used which, in the dark state is randomly coiled and cell impermeable but upon illumination becomes helical and cell permeable and can be used to deliver drugs into the cells. Upon illumination with UV light of suitable wavelength the azobenzene linker will change from a trans to a cis form and this will convert the randomly coiled cell impermeable peptide into an α helical permeable form. Thus a series of peptides have been designed with different arginine mutations which develop an arginine patch in the helical form. This arginine patch would help in cell permeability by interacting with cell surface glycans. The method could potentially be used to deliver drugs into cells in presence of light.
6
Vellore, Janarthanan Mohanraj. "Formulation of chitosan-based nanoparticles for delivery of proteins and peptides." Curtin University of Technology, School of Pharmacy, 2003. http://espace.library.curtin.edu.au:80/R/?func=dbin-jump-full&object_id=14517.
Повний текст джерелаАнотація:
Delivery of complex molecules such as peptides, proteins, oligonucleotides and plasmids is an intensively studied subject, which has attracted considerable medical and pharmaceutical interest. Encapsulation of these molecules with biodegradable polymers represents one way of overcoming various problems associated with the conventional delivery of macromolecules, for example instability and short biological half-life. The use of carriers made of hydrophilic polysaccharides such as chitosan, has been pursued as a promising alternative for improving the transport of biologically active macromolecules across biological surfaces. The development of nanoparticles as a delivery system also has major advantages of achieving possible drug protection, controlled release and drug targeting by either a passive or an active means. The aim of this study was to develop a simple and effective method to formulate biodegradable nanoparticles for the delivery of a model protein-bovine serum albumin (BSA) and an angiogenesis inhibitor, arginine-rich hexapeptide (ARE peptide). Major factors which determine nanoparticle formation and loading of the protein and the peptide as well as the underlying mechanisms controlling their incorporation and release characteristics were investigated. The preparation technique, based on the complex coacervation process, is extremely mild and involves the mixture of two aqueous solutions (chitosan and dextran sulfate) at room temperature. The formation of nanoparticles is dependent on the concentrations of chitosan (CS) and dextran sulfate (DS); particles with size, of 257 to 494nm can be obtained with 0.1%w/v solutions of CS and DS. Zeta potential of nanoparicles can be modulated conveniently from -34.3mV to +52.7mV by varying the composition of the two ionic polymers.Both bovine BSA and the ARH peptide were successfully incorporated into CS-based nanoparticles, mainly via an electrostatic interaction, with entrapment efficiency up to 100% and 75.9% for the protein and peptide respectively. Incorporation of both the protein and peptide into nanoparticles resulted in an increase in size suggesting their close association with the nanoparticle matrix material. The difference in sign and magnitude of zeta potential of empty and macromolecules-loaded nanoparticles supports the hypothesis that protein and peptide association with nanoparticles can be modulated by their ionic interaction with the oppositely charged ionic polymer (DS) in the nanoparticles. The release of BSA from the nanoparticles was very slow in water compared to that in l0mM phosphate buffer pH 7.4; whereas, ARH peptide showed extremely low level of release in water at the low ratio of DS but at the high ratio of DS, its release was in biphasic fashion, with an initial burst effect followed by an almost constant but very slow release up to 7 days in both water and 1 OmM phosphate buffer (pH 7.4). It was found that, unlike ARH peptide, the percentage of BSA released was relatively slower for the nanoparticles with a high ratio of DS. It is speculated that this difference in the release behaviour of BSA and ARH peptide, could be due to the effect of molecular size of the compounds and their interaction with the polymer matrix of the nanoparticle. The results of this study suggest that these novel CS/DS nanoparticulate system, prepared by a very mild ionic crosslinking technique, have potential to be a suitable carrier for the entrapment and controlled release of peptides and proteins.
7
Karthauser, Zoe. "A new approach to drug delivery : non-peptidic, high load macrocyclic alternatives to cell penetrating peptides." Thesis, University of East Anglia, 2013. https://ueaeprints.uea.ac.uk/48136/.
Повний текст джерелаАнотація:
Calixarenes are versatile macrocycles formed from the condensation of para-tertbutyl- phenol and formaldehyde. Chapter 1 describes the synthesis of these molecules and how conformational control and selective functionalisation can give an array of molecules with customised properties; this allows for various applications including those of biological relevance. The copper catalysed alkyne-azide cycloaddition (CuAAC) reaction is also introduced as a tool for functionalising calixarenes. The phenomenon of cell penetration is of interest where a molecule has an intracellular target, for example gene therapy, delivery of cytotoxic agents or cellular imaging. Chapter 2 introduces the mechanisms of cell uptake and the design and applications of cell penetrating peptides. Calixarenes are presented as alternatives to cell penetrating peptides and the work published to date on intracellular delivery of calixarenes is summarised. A synthetic route for calixarenes with variable fluorescent dyes and different functionalities on the upper rim via a common intermediate is presented. Synthesis of an analogue featuring guanidinium groups on the upper rim was achieved using carboxybenzyl (Cbz) protecting groups as a less labile alternative to butoxycarbonyl (Boc) groups. The syntheses of analogues with varied linkers for attachment of the dye are also presented. Biological evaluation revealed that the dynamics of cellular uptake and the intracellular localisation were sensitive to the upper-rim functionalisation and the dye molecule. The linker attaching the dye had less impact. Chapter 3 describes the suitability of calixarenes as scaffolds to form glycoconjugates. These can be used to target Pseudomonas aeruginosa; research towards development of novel treatments of infections from this pathogen is summarised. A route that has been developed towards bifunctional calixarenes featuring a fluorescent tag and points of attachment for sugars via CuAAC reactions is presented. The use of alkyne protecting groups to maintain the integrity of the scaffold during transformations was found to be particularly important.
8
Mäe, Maarja. "Rational modifications of cell-penetrating peptides for drug delivery : Applications in tumor targeting and oligonucleotide delivery." Doctoral thesis, Stockholms universitet, Institutionen för neurokemi, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-8374.
Повний текст джерелаАнотація:
High molecular weight biomolecules are becoming important in the development of new therapeutics. However, their size and nature creates a major limitation for their application – poor penetration through biological membranes. A new class of peptides, cell-penetrating peptides (CPPs), has shown the capability to transport various macromolecules inside the cells. However, there are at least two limiting factors for successful application of CPPs: the lack of cell-type specificity and restricted bioavailability resulting from endocytic uptake of CPPs and entrapment in endosomal compartments. This thesis aims at designing delivery vehicles for therapeutic substances. In papers I-III, the CPPs have been rationally modified in order to achieve in vivo selectivity towards cancer cells. The first two papers employ tumor homing peptides as targeting moieties coupled to the N-termini of CPPs. In the third paper, a CPP is C-terminally prolonged with a matrix metalloproteinase 2 (MMP-2) specific cleavage site followed by an inactivating amino acid sequence. In tissues overexpressing MMP-2, i. e. in proximity to cancer, the CPP is activated after proteolytic removal of the inactivating sequence, thus the cargo can be transported inside the cells. In paper IV, several CPPs have been N-terminally modified with a stearyl moiety and applied for the delivery of splice-correcting oligonucleotides. We show that stearyl-TP10 is as effective in oligonucleotide delivery as Lipofectamine™ 2000. Moreover, stearyl-TP10 has preserved efficacy in serum and is not toxic to cells. In conclusion, the rational modifications of CPPs greatly potentiate their application in cargo delivery both in vitro and in vivo.
9
Barman, Poulami. "The interaction of peptides with functionalized carbon nanotubes /." Online version of thesis, 2009. http://hdl.handle.net/1850/8688.
Повний текст джерела
10
Mozaffari, Saghar. "Amphiphilic Cell-Penetrating Hybrid Cyclic-Linear Peptides as a Drug Delivery System." Chapman University Digital Commons, 2019. https://digitalcommons.chapman.edu/pharmaceutical_sciences_dissertations/2.
Повний текст джерелаАнотація:
A number of cyclic peptides containing a positively charged ring composed of arginine residues attached to hydrophobic tail made of tryptophan residues through a lysine linker namely [R5K]W5, [R6K]W5, [R5K]W6, [R7K]W5, [R5K]W7, [R6K]W6, and [R7K]W7 were synthesized and evaluated as molecular transporters. The peptides were evaluated for their ability to deliver, fluorescence-labeled cell-impermeable negatively charged phosphopeptide (F′-GpYEEI), and fluorescent labeled anti-HIV drugs (F′-FTC and F′-d4T). The results indicated that the presence of positively charged arginine residues on the ring and hydrophobic tryptophan residues in a sequential linear outside the ring was an optimal approach to improve the intracellular uptake of cargo molecules through non-covalent interactions. Some of these peptides were also evaluated for their efficiency for intracellular delivery of siRNA to triple-negative breast cancer cell lines in the presence and absence of 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE). [R6K]W6 and [R5K]W5 were found to be very efficient in the delivery of siRNA. Furthermore, co-formulation of peptides with lipid DOPE significantly enhanced the efficiency of siRNA delivery compared to peptide alone. Silencing of kinesin spindle protein (KSP) and Janus kinase 2 (JAK2) was evaluated in MDA-MB-231 cells in the presence of the peptides. The addition of DOPE significantly enhanced the silencing efficiency for all selected peptides.
A chemotherapeutic drug, doxorubicin (Dox) was covalently conjugated to the cyclic peptide [R5K]W7A and linear peptide R5KW7A, and the biological activity was evaluated in cell-based assays. Comparative antiproliferative assays between covalently conjugated peptide-Dox and the corresponding noncovalent physical mixtures of the peptides and Dox were performed. The conjugation of Dox with cyclic [R5K]W7A-Dox exhibited similar antiproliferative activity compared to Dox alone after 72 h incubation time in all cancer cell lines, such as leukemia, ovarian and gastric cancer cells. However, [R5K]W7A-Dox significantly reduced the cell cytotoxicity in normal cell lines such as normal heart muscle and normal kidney cells after 72 h when compared with Dox alone. These results revealed that this cyclic peptide prodrug can be used as a potential candidate for the treatment of cancer cells with reduced side effects against normal cells in the body.
11
Stulz, Anja [Verfasser], and Heiko [Akademischer Betreuer] Heerklotz. "Biophysical interactions of peptides and their analogues with lipid membranes: applications in drug development and drug delivery." Freiburg : Universität, 2019. http://d-nb.info/1211956326/34.
Повний текст джерела
12
Cooke, Fiona Ghina Mary. "Can exosomes be used as drug delivery vesicles?" Thesis, University of St Andrews, 2018. http://hdl.handle.net/10023/13657.
Повний текст джерелаАнотація:
The inflammatory arthritis Ankylosing Spondylitis (AS) is linked to the human leucocyte antigen HLA-B27. HLA-B27 is thought to drive AS because it misfolds during assembly in the endoplasmic reticulum (ER), inducing ER cell stress. Modulating HLA-B27 folding in the ER is therefore a therapeutic target pathway. The recent discovery of polymorphisms in the ER-resident peptidase ERAP1 that can impact on HLA-B27 and AS, makes ERAP1 one such target. Exosomes are small, typically 50-200 nm sized particles, formed in the endosomal recycling pathway, which can be released into the extracellular environment. Exosomes have a wide range of biological activities depending on the cell type of origin, and on the delivered cargo, which can include bio-active proteins, lipids, mRNA and miRNA. There is interest in the use of exosomes as drug delivery agents. Here, exosomes were studied as a delivery agent to modulate ERAP1, as a potential therapeutic tool for the treatment of AS. Exosomes, isolated from cell lines including CEM and Jurkat (T cell lineage), Jesthom (B cell lineage), U937 (monocyte lineage) and the epithelial HeLa cell line, were characterized by nanoparticle tracking analysis, flow cytometry and immunoblotting using markers including CD9, CD63, CD81 and TSG101. Differential expression of these markers in the immune cell lines indicated the complexity of defining exosomes. EVs were then tested using cell penetrating peptides, electroporation, lipid transfection and sonication for their ability to load FITC-siRNA or FITC-antibody as cargo. Significantly, post-loading RNase A or trypsin incubation demonstrated that many techniques do not lead to efficient cargo loading of exosomes. Sonication proved the most effective technique, with up to 30% efficiency. Loading of exosomes with ERAP1-targetted siRNA did not however lead to notable ERAP1 inhibition. The data indicates that external loading of exosomes with cargo remains a significant challenge in developing exosomes as therapeutic tools.
13
Delfino, Davi Barbosa [UNESP]. "Sistemas drug delivery aplicados a novos inibidores de topoisomerases estruturalmente derivados de toxinas bacterianas." Universidade Estadual Paulista (UNESP), 2011. http://hdl.handle.net/11449/87961.
Повний текст джерелаАнотація:
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Este trabalho descreve a síntese de peptídeos em fase sólida (SPFS) derivados de toxinas bacterianas, tais como CcdB e ParE, e a produção de sistemas nanoestruturados como lipossomas e microemulsões. As toxinas intracelulares, produzidas por sistemas de morte pós-segregacional (PSK) em bactérias são exemplos recentes de agentes inibidores de enzimas fundamentais para a reprodução do microrganismo. Resultados promissores foram obtidos em relação a inibição da atividade da DNA girase, por derivados peptídicos destas duas proteínas. In vitro, os valores de concentração inibitória têm sido abaixo de 5 μmol.L-1, porém ensaios in vivo não demonstraram reprodutibilidade, basicamente devido à baixa permeabilidade da membrana bacteriana a estes derivados. Desta forma, foram produzidos lipossomas e microemulsões com o objetivo de promover o acesso de moléculas peptídicas sintéticas, derivadas do CcdB e ParE, ao meio intracelular e, conseqüentemente, aos seus alvos: DNA girase ou topoisomerase IV. Lipossomas do tipo SUV (small unilamellar vesicles) foram preparados por extrusão a partir de fosfatidilcolina de soja e estearilamina e mostraram uma eficiência de encapsulação de 77% e inibiram o crescimento tanto de bactéria Gram positiva quanto Gram negativa em 58 e 75%, respectivamente. Sistemas microemulsionados a base de fosfatidilcolina de soja, Tween 20, etanol e ácido oléico apresentaram uma incorporação do peptídeo acima de 90% e a formulação com 15% de ácido oléico e CcdBET2 a 4 μmol.L-1 apresentou uma inibição do crescimento de bactéria Gram negativa de 75,5%. O diâmetro dos lipossomas foi medido por espalhamento dinâmico de luz e as microemulsões foram caracterizadas por microscopia de luz polarizada e sua viscosidade determinada por reologia. Portanto, lipossomas e microemulsões podem ser utilizados como sistemas de drug delivery para análogos peptídicos derivados do CcdB e do ParE
This work describes the synthesis of peptides derived from bacterial toxins, such as CcdB and ParE, by solid phase peptide synthesis (SPPS) and the production of nanostructured systems such as liposomes and microemulsions. Intracellular toxins produced by systems of killer post-segregational (PSK) in bacteria are recent examples of inhibitors of key enzymes for the reproduction of the microorganism. Promising results were obtained for the inhibition of DNA gyrase activity by peptide derivatives of these proteins. In vitro, the IC100 values have been below 5 μmol.L-1, but not demonstrated in vivo reproducibility, mainly due to the low permeability of the bacterial cell to these derivatives. Thus, the aim with this work was develop of liposomes and microemulsions to promote access of synthetic peptide molecules derived from the CcdB and ParE, to the intracellular medium and consequently to their targets: DNA gyrase and topoisomerase IV. Liposomes SUV type (small unilamellar vesicles) were prepared by extrusion from soybean phosphatidylcholine and estearilamina and showed an encapsulation efficiency of 77% and inhibited the growth of both Gram positive and Gram negative in 58 and 75% respectively. Microemulsion systems based soybean phosphatidylcholine, Tween 20, ethanol and oleic acid showed an incorporation of the peptide above 90% and the specific formulation with 15% oleic acid and the 4 μmol.L-1 CcdBET2 incorporate showed a growth inhibition of Gram negative of 75.5%. The diameter of liposomes was measured by dynamic light scattering and microemulsions were characterized by polarized light microscopy and its viscosity determined by rheology. Therefore, liposomes and microemulsions may be used as drug delivery systems for peptide analogues derived from the CcdB and ParE
14
Silva, Nigenda Ezequiel. "Synthesis of drug delivery systems based on pantothenic acid and cationic amphiphilic peptides modifications." Thesis, University of Glasgow, 2017. http://theses.gla.ac.uk/8917/.
Повний текст джерелаАнотація:
The constant problems encountered in the fields of medicinal and pharmaceutical chemistry, especially those related to the side effects of drug candidates, have risen the concern of developing methods that can help us achieve the therapeutic effect without undesired properties. This thesis describes the development of two different Drug Delivery Systems based on the modification of natural occurring molecules. The first one is directed to the treatment of parasitic tropical diseases. The alteration of pantothenic acid with the introduction of a double bond has proved to increase the uptake of fluorescent labelled molecules in different model systems with low cytotoxicity. The concept of this Drug Delivery System relies on the necessity of the parasites to consume the host’s pantothenic acid for their own biological processes. Due to their inability to synthesise this vitamin along with the huge supply they need to survive, it was hypothesised that the increased uptake of CJ-15,801 would allow us to attach interesting molecules that could be selectively delivered into parasites. The second example of a Drug Delivery System presented in this work is based on peptides released by cells of the immune system. The so called Cationic Amphiphilic Peptides are released by an organism that is under the attack of potential pathogens. Due to their physicochemical properties, they can stop an infection by direct killing of microorganisms by different mechanisms. Either by the membrane disruption or internalisation and intracellular targeting, the presence of positively charged residues play a major role on the activity of these peptides. By substitution of the natural occurring lysine and arginine residues with a new class of phosphonium based amino acids, a new class of cationic amphiphilic peptides was synthesised. Fluorescent versions of these peptides have allowed us to investigate their properties. They are characterised by their ability to cross cellular membranes with relatively low toxicity compared to the natural occurring versions of the sequences and even though their direct antimicrobial activity is diminished they can be used as potential Cell Penetrating Peptides. Finally, due to the nature of the cation present in these new peptides, it is theorised that they can have certain selectivity to deliver drugs into mitochondria. Although further studies to prove this need to be done, an initial experiment is reported at the end of this work.
15
Liang, Wanling, and 梁婉玲. "Formulation of nucleic acid with pH-responsive amphipathic peptides for pulmonary delivery." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2014. http://hdl.handle.net/10722/207996.
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16
Akasov, Roman. "Novel 3D in vitro models based on multicellular tumor spheroids to test anticancer drugs and drug delivery vehicles." Thesis, Strasbourg, 2017. http://www.theses.fr/2017STRAF013/document.
Повний текст джерелаАнотація:
Les sphéroïdes multicellulaires tumoraux (SMT) constituent un outil prometteur dans le domaine de l’étude biologique des tumeurs. Le but de la thèse était de développer une technique de la formation de SMT et de démontrer la disponibilité de ces sphéroïdes comme modèle in vitro 3D pour tester l’efficacité de principes actifs anticancéreux ainsi que celle de formulations de délivrance de médicaments. L'effet d’auto-assemblage de cellules induit par une addition des peptides RGD cycliques a été étudié pour 16 lignées cellulaires de différentes origines. Le peptide cyclique RGDfK et sa modification avec le cation triphenylphosphonium (TPP) ont permis de mettre en évidence l’induction de formation de sphéroïdes. Les sphéroïdes ont été employés comme modèles pour évaluer la cytotoxicité de principes actifs antitumoraux (doxorubicine, curcumine, temozolomide) et un certain nombre de formulations nano- et micrométriques (microréservoirs, nano-émulsions et micelles)Multicellular tumor spheroids (MTS) are a promising tool in tumor biology. The aim of the Thesis was to develop a novel highly reproducible technique for MTS formation, and to demonstrate the availability of these spheroids as 3D in vitro model to test anticancer drugs and drug delivery vehicles. Cell self-assembly effect induced by an addition of cyclic RGD-peptides directly to monolayer cultures was studied for 16 cell lines of various origin. Cyclo-RGDfK peptide and its modification with triphenylphosphonium cation (TPP) were found to induce spheroid formation. The spheroids were used as a model to evaluate the cytotoxicity of antitumor drugs (doxorubicin, curcumin, temozolomide) and a number of nano- and micro- formulations (microcontainers, nano-emulsions and micelles)
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Qian, Ziqing. "Developments and Applications of Cyclic Cell Penetrating Peptides." The Ohio State University, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=osu1405340891.
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Regberg, Jakob. "Cell-penetrating peptide based nanocomplexes for oligonucleotide delivery." Doctoral thesis, Stockholms universitet, Institutionen för neurokemi, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-133794.
Повний текст джерелаАнотація:
Oligonucleotide-based drugs hold great promise for the treatment of many types of diseases, ranging from genetic disorders to viral infections and cancer. The problem is that efficient delivery across the cell membrane is required for oligonucleotides to have their desired effect. Cell-penetrating peptides (CPPs) provide a solution to this problem. CPPs are capable of transporting cargoes such as drugs or nucleic acids for gene therapy into the cell, either by covalent conjugation to the cargo or by non-covalent complex formation. This thesis is focused on the development of a class of peptides called PepFects, peptides with fatty acid modifications capable of forming nanoparticle-sized complexes with oligonucleotides. These complexes are efficiently internalized by many different cell types and are generally non-toxic and non-immunogenic. We have developed a number of novel PepFect peptides and a quantitative structure-activity model to predict the biological effect of our peptides. In addition, the involvement of scavenger receptors class A in the endocytic uptake of PepFect complexes as well as other CPPs and polymeric transfection agents was studied. Lastly, we have developed a series of PepFect peptides for delivery across the blood-brain barrier and a model system mimicking the blood-brain barrier in order to evaluate the passage of these peptides. The general aim of this thesis is to improve the understanding of intracellular delivery of oligonucleotides with PepFect peptides from both a chemical and a biological viewpoint, and further improve the efficacy of this delivery system with the long-term goal of making it useful in clinical settings.
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Delfino, Davi Barbosa. "Sistemas drug delivery aplicados a novos inibidores de topoisomerases estruturalmente derivados de toxinas bacterianas /." Araraquara [s.n.], 2011. http://hdl.handle.net/11449/87961.
Повний текст джерелаАнотація:
Orientador: Reinaldo MarchettoCoorientador: Saulo Santesso Garrido
Banca: Marlus Chorilli
Banca: Pietro Ciancaglini
Resumo: Este trabalho descreve a síntese de peptídeos em fase sólida (SPFS) derivados de toxinas bacterianas, tais como CcdB e ParE, e a produção de sistemas nanoestruturados como lipossomas e microemulsões. As toxinas intracelulares, produzidas por sistemas de morte pós-segregacional (PSK) em bactérias são exemplos recentes de agentes inibidores de enzimas fundamentais para a reprodução do microrganismo. Resultados promissores foram obtidos em relação a inibição da atividade da DNA girase, por derivados peptídicos destas duas proteínas. In vitro, os valores de concentração inibitória têm sido abaixo de 5 μmol.L-1, porém ensaios in vivo não demonstraram reprodutibilidade, basicamente devido à baixa permeabilidade da membrana bacteriana a estes derivados. Desta forma, foram produzidos lipossomas e microemulsões com o objetivo de promover o acesso de moléculas peptídicas sintéticas, derivadas do CcdB e ParE, ao meio intracelular e, conseqüentemente, aos seus alvos: DNA girase ou topoisomerase IV. Lipossomas do tipo SUV (small unilamellar vesicles) foram preparados por extrusão a partir de fosfatidilcolina de soja e estearilamina e mostraram uma eficiência de encapsulação de 77% e inibiram o crescimento tanto de bactéria Gram positiva quanto Gram negativa em 58 e 75%, respectivamente. Sistemas microemulsionados a base de fosfatidilcolina de soja, Tween 20, etanol e ácido oléico apresentaram uma incorporação do peptídeo acima de 90% e a formulação com 15% de ácido oléico e CcdBET2 a 4 μmol.L-1 apresentou uma inibição do crescimento de bactéria Gram negativa de 75,5%. O diâmetro dos lipossomas foi medido por espalhamento dinâmico de luz e as microemulsões foram caracterizadas por microscopia de luz polarizada e sua viscosidade determinada por reologia. Portanto, lipossomas e microemulsões podem ser utilizados como sistemas de drug delivery para análogos peptídicos derivados do CcdB e do ParE
Abstract: This work describes the synthesis of peptides derived from bacterial toxins, such as CcdB and ParE, by solid phase peptide synthesis (SPPS) and the production of nanostructured systems such as liposomes and microemulsions. Intracellular toxins produced by systems of killer post-segregational (PSK) in bacteria are recent examples of inhibitors of key enzymes for the reproduction of the microorganism. Promising results were obtained for the inhibition of DNA gyrase activity by peptide derivatives of these proteins. In vitro, the IC100 values have been below 5 μmol.L-1, but not demonstrated in vivo reproducibility, mainly due to the low permeability of the bacterial cell to these derivatives. Thus, the aim with this work was develop of liposomes and microemulsions to promote access of synthetic peptide molecules derived from the CcdB and ParE, to the intracellular medium and consequently to their targets: DNA gyrase and topoisomerase IV. Liposomes SUV type (small unilamellar vesicles) were prepared by extrusion from soybean phosphatidylcholine and estearilamina and showed an encapsulation efficiency of 77% and inhibited the growth of both Gram positive and Gram negative in 58 and 75% respectively. Microemulsion systems based soybean phosphatidylcholine, Tween 20, ethanol and oleic acid showed an incorporation of the peptide above 90% and the specific formulation with 15% oleic acid and the 4 μmol.L-1 CcdBET2 incorporate showed a growth inhibition of Gram negative of 75.5%. The diameter of liposomes was measured by dynamic light scattering and microemulsions were characterized by polarized light microscopy and its viscosity determined by rheology. Therefore, liposomes and microemulsions may be used as drug delivery systems for peptide analogues derived from the CcdB and ParE
Mestre
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Capriotti, Lisa A. "Surface-induced peptide folding." Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file, 347 p, 2009. http://proquest.umi.com/pqdweb?did=1824967161&sid=6&Fmt=2&clientId=8331&RQT=309&VName=PQD.
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Fernandez, Christian Antonio. "Development of PEGylated polyacridine peptides for in vivo gene delivery of plasmid DNA." Diss., University of Iowa, 2010. https://ir.uiowa.edu/etd/800.
Повний текст джерелаАнотація:
Gene therapy provides an opportunity to ameliorate several genetic disorders and treat numerous diseases by using nucleic acid-based materials to modulate gene activity. However, the greatest challenge for successful gene therapy applications remains delivery. Two general approaches are currently under investigation to improve gene delivery efficiencies. The first is by encapsulating therapeutic genes into modified viruses that are effective at transfecting cells but that have also caused serious side effects during clinical evaluations in 1999 and 2003. In contrast, non-viral gene therapy provides the safety of conventional pharmaceutical products, but possesses inadequate transfection efficiencies for clinical use. Successful non-viral gene delivery systems require evasion of the reticuloendothelial system (RES) while in circulation, a targeting ligand for efficient cellular uptake, and perhaps several additional components for efficient cellular disposition once the carrier has been internalized.
Engineering sophisticated gene delivery systems requires modular designs that are well characterized and optimized to circumvent each limiting barrier associated with gene delivery. The following thesis is focused on developing stabilized DNA polyplexes for in vivo applications and coupling their administration with current physical methods of non-viral gene delivery. The aim behind this approach is to systematically prepare gene carriers and evaluate their ability to maintain DNA transfection competent in order to determine which bioconjugate is the most successful for ultimately creating gene carriers that do not require physical interventions for gene expression.
The non-viral gene delivery systems presented in the thesis are based on PEGylated polyacridine peptides that bind to DNA predominantly by intercalation rather than by ionic interactions with DNA. The initial experimental chapters deal with the discovery of these novel DNA polyplexes, and the latter chapters focus on the optimization of their design for targeted in vivo gene delivery. The results demonstrate that PEGylated polyacridine DNA polyplexes possess improved compatibility for in vivo administration and that their flexible design is beneficial for preparing multi-component gene delivery systems.
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Nadkarni, Priya. "PULMONARY DELIVERY OF ANORECTIC GUT SECRETED PEPTIDES FOR APPETITE SUPPRESSION IN RATS." VCU Scholars Compass, 2009. http://scholarscompass.vcu.edu/etd/1941.
Повний текст джерелаАнотація:
This dissertation project aimed to demonstrate that pulmonary delivery of two anorectic gut secreted peptides, peptide YY (PYY) and oxyntomodulin (OXM) enabled food intake suppression and reduced body weight gain in rats via their systemic absorption from the lung and interaction with the brain. After PYY and OXM were administered to the lungs at varying doses, food intake and body weight gain were monitored in freely feeding rats. Significant 30-35 % food intake suppression was achieved for 4-6 h following pulmonary administration of endogenously active PYY3-36 and OXM1-37 at 0.80 and 0.50 mg/kg, respectively. Moreover, when administered daily for 7 days, these peptides enabled significant reduction of body weight gain by 39.4 and 62.3 %, respectively. However, neither of their active fragment peptides, PYY13-36, OXM30-37 and NAc-OXM30-37 was effective at doses equimolar to the effective doses of PYY3-36 and OXM1-37. For PYY3-36, its pulmonary administration caused c-Fos activation in the hypothalamus arcuate nucleus (ARC) only, which was concurrent to reduced orexigenic neuropeptide Y (NPY), suggesting its appetite suppression was mediated via the central nervous system (CNS). In contrast, OXM1-37 caused c-Fos activation in both the hypothalamus ARC and brainstem AP, which implied the involvement of the CNS control and vagal stimulation for this peptide. As it was clear that these effects resulted from their lung absorption and increased plasma levels, the pharmacokinetics of one of the peptides, PYY3-36 was characterized following pulmonary administration. The plasma profiles were dose-proportional and kinetically, non “flip-flop”, yielding the highest PYY3-36 concentrations (Cmax) of 75.0±9.3 and 726.3±69.0 ng/ml at 0.08 and 0.80 mg/kg, respectively, at 10 min. According to a new kinetic model developed in this project, the percent absolute bioavailability (% F) was estimated to be 12-14 %, as derived from the lung absorption (ka) and non-absorptive loss rate constant (knal) of 0.03 min-1 and 0.17-0.22 min-1, respectively. Overall, this research provided the first proof-of-concept for effective appetite suppression with pulmonary delivery of anorectic gut secreted peptides via systemic absorption.
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Deshmukh, Ameya. "MMP-Degradable Biosensors: Applications in Drug Delivery and Personalized Medicine." The Ohio State University, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=osu1585925271421393.
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Albarran, Brian. "TAT-streptavidin : a novel drug delivery vector for the intracellular uptake of macromolecular cargo /." Thesis, Connect to this title online; UW restricted, 2006. http://hdl.handle.net/1773/8016.
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Barthold, Sarah [Verfasser], and Claus-Michael [Akademischer Betreuer] Lehr. "Nanotechnology enabled drug delivery of proteins and peptides to the lung / Sarah Barthold. Betreuer: Claus-Michael Lehr." Saarbrücken : Saarländische Universitäts- und Landesbibliothek, 2016. http://d-nb.info/1104733315/34.
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Wang, Jingda. "IN VITRO COMPARATIVE STUDY OF THE BINDING AFFINITY AND TARGETED-DRUG DELIVERY EFFICIENCY OF EGFR-TARGETING PEPTIDES." Scholarly Commons, 2021. https://scholarlycommons.pacific.edu/uop_etds/3750.
Повний текст джерелаАнотація:
Peptides have been used as targeting ligands in targeted drug delivery. Conjugating peptides to cytotoxicity agents via a linker to build peptide-drug conjugate (PDC) is a promising targeting strategy. The binding affinity of the peptide ligand and the receptor plays a crucial role in the PDC targeted drug delivery. Although the ligand binding which can be used in targeted drug delivery has been established conceptually, the quantitative or semi-quantitative contribution of binding affinity in targeting efficiency has not been fully explored. The optimal range of binding affinity of the peptide for targeted delivery remains unknown. Therefore, there is a lack of knowledge on the relationship between the peptide binding affinity and targeted drug delivery efficiency. The major steps in peptide drug delivery include cellular binding, cellular internalization, and tumor cells killing. In this study, three EGFR-targeting peptides with binding affinity levels ranging from 22 nM to 1.25 μM were selected to study their targeted drug delivery efficiency. The cellular binding study of FITC labeled peptides showed that peptide GE11 with the highest binding affinity had the highest cellular binding among three peptides. PEP11 peptide showed enhanced cellular binding compared to the L1 peptide. Moreover, GE11 also showed the selectivity of cellular binding between EGFR-positive cells and EGFR-negative cells. The cellular distribution showed that GE11-FITC could be successfully internalized into cells. The uptake mechanism studies demonstrated that the cellular uptake of GE11-FITC was based on receptor-mediated endocytosis, meaning that the cellular binding of GE11 was able to trigger the endocytosis. MMAE, a non-selective anticancer agent, was conjugated to the peptides through a protease-sensitive linker. The cytotoxicity assay showed that GE11-MMAE had the highest drug delivery efficiency and selectivity of three peptides, with 200 folds lower IC50 value than MMAE in EGFR-positive cells and 1000 times lower in EGFR-negative cells. PEP11-MMAE also showed an enhanced drug delivery than MMAE and L1-MMAE. L1-MMAE failed to show a significant difference with MMAE. Cellular binding kinetics results revealed that GE11-FITC had a higher rate of cellular uptake than PEP11-FITC.
In conclusion, in the range from micromolar to the nanomolar, higher binding affinity of peptide ligand will contribute to higher cellular binding, targeted drug delivery efficiency, and cellular uptake rate. These results suggest that in EGFR-targeting delivery, the nanomolar level binding affinity is necessary for peptides to be used as targeting moiety in the targeted drug delivery. This study provides a starting point for further quantitative probing of the optimal binding affinity for designing and developing peptide ligand-based targeted delivery.
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Lei, Xia. "Study of Zwitterionic Functionalized Materials for Drug Delivery and Protein Therapeutics." University of Akron / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=akron1555511296878391.
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Nadal, Bufi Ferran. "Peptide-based drugs to inhibit LDH5, a potential target for cancer therapy." Thesis, Queensland University of Technology, 2022. https://eprints.qut.edu.au/232526/1/Ferran_Nadal%20Bufi_Thesis.pdf.
Повний текст джерелаАнотація:
This thesis investigates novel strategies to target lactate dehydrogenase 5 (LDH5), a protein involved in cancer. After decades of research without success, this thesis reports the development of the first molecules able to inhibit the activity of LDH5 with an alternative mechanism of action: disrupting its structure. To do that, an emerging class of drugs called peptides are explored. The lead peptide of this work successfully kills breast cancer cells via LDH5 inhibition. The validation of this strategy is relevant because it can be applied to many other cancer targets that have been traditionally considered “undruggable”.
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Uesaka, Akihiro. "Precise Structural and Functional Control of Molecular Assemblies Composed of Amphiphilic Peptides Having a Hydrophobic Helical Block." 京都大学 (Kyoto University), 2015. http://hdl.handle.net/2433/199273.
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Morin, Zetterberg Malin. "Development and Evaluation of Lipodisks Intended for Use as Biomimetic Membranes and Drug Carriers." Doctoral thesis, Uppsala universitet, Analytisk kemi, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-268667.
Повний текст джерелаАнотація:
Polyethylene glycol-stabilized lipodisks have emerged as a novel type of lipid-based nanoparticles with high potential as both drug carriers and biomimetic membranes. In this thesis we assess both of these applications, and show how the properties of the lipodisks can be further developed and optimized. Initially, we show that the antimicrobial peptides melittin, alamethicin and magainin 2, in spite of their very different physico-chemical properties and suggested modes of action on membranes, all have high affinity to lipodisks. Using melittin as a model peptide, we confirm a maintained antimicrobial effect of disk-formulated peptides. We also show that melittin dissociates slowly from the disks, resulting in extended drug release and prolonged antibacterial effect. Additionally, we present evidence that the peptide is protected against enzymatic degradation when formulated in the disks. Further, we develop a stable HPLC-MS system with immobilized lipodisks as model membranes. The stability of the system is confirmed by drug partitioning analysis using 15 different drug compounds. We also show how the lipodisk column can be supplemented with cyclooxygenase by in situ incorporation of the protein in the lipodisks. The specific binding of the protein to the disks is confirmed using QCM-D. Finally, by changing the polymer length and applying a new preparation protocol, we have optimized the lipodisks for use as drug carriers and biomimetic membranes. Previous lipodisk studies have been conducted on systems containing PEG-lipids with polymer molecular weights of 2000 or 5000 Da. Also, conventional protocols for the preparation of lipodisks typically require a PEG-lipid concentration of 15 mol% or more. Here we show that stable lipodisks can also be produced using PEG-lipids with a 1000 Da molecular weight polymer and that the use of shorter PEG-lipids dramatically improve the amount of lipodisks that can be immobilized on silica surfaces. Moreover, through the development of a method in which lipid mixtures are sonicated at low temperatures, we produce lipodisks containing as little as 2 mol% PEG-lipid. We present data verifying that these disks are superior to disks with higher PEG-lipid content in terms of their ability to incorporate externally added PEG-lipids functionalized with targeting agents.
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Alsoraj, Monerah. "siRNA depletion of endocytic proteins and pathways for analysing the cellular uptake of cell penetrating peptides as vectors for drug delivery." Thesis, Cardiff University, 2011. http://orca.cf.ac.uk/54430/.
Повний текст джерелаАнотація:
Cell-penetrating peptides (CPPs) have the potential to deliver a host of macromolecular therapeutics into cells including peptides, proteins, and nucleotides. The mechanism by which they are internalised has been hotly-disputed but is important if improvements are to be made in their delivering capacities. Endocytosis is thought to be of significant importance but identifying the exact uptake mechanism has been difficult due predominantly to a lack of specific tools. Multiple pathways have been reported to contribute to uptake, including macropinocytosis and those regulated by clathrin and cavaeolin-1. The aim of this thesis was to utilise siRNA-depletion to develop cell models with defects in specific endocytic proteins and pathways that could then be utilised to study the uptake of drug delivery vectors such as CPPs. Targeted pathways were those regulated by clathrin heavy chain, dynamin-2, caveolin-1, flotillin-1 and P21-activated kinase (PAK-1). Significant variation between cell lines emerged in the expression of these proteins and the ease with which they could be depleted. Single siRNA sequences were, however, discovered that effectively depleted these proteins and using a variety of endocytic probes the effects of depletion could be determined. Eventually, model cell lines were generated that were measurably defective in at least one of the five different endocytic pathways and these were tested to determine routes utilised by two well characterised CPPs, HIV-Tat and octaarginine. Only cells depleted of pak-1 protein and thus macropinocytosis were defective in CPP uptake. Further analysis revealed defective actin organisation in these cells that could have caused the effects and support data presented here and elsewhere on actin disruption with cytochalasin D. With comparative studies using pharmacological inhibitors of endocytic pathways these methods provide new tools to study drug delivery systems as shown here for CPPs and also for polyplexes through a collaboration with the University of Ghent, Belgium.
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Tinajero, Díaz Ernesto. "Hybrid block and graft copolymers made from macrolactones and α-amino acids for applications as drug delivery nanosystems". Doctoral thesis, Universitat Politècnica de Catalunya, 2019. http://hdl.handle.net/10803/667299.
Повний текст джерелаАнотація:
Naturally produced peptides or proteins can be regarded as highly refined polymers. When synthetic polymers are married to proteins or peptides, the resulting bioconjugates can synergistically combine the properties of the individual components and overcome their separate limitations. This Thesis is focused on the study of hybrid copolymers based on polypeptides and polymacrolactones. Block and graft copolymers have been synthesized by making use of the ring opening polymerization method (ROP) mainly and extensively characterized including both their chemical structure and their structure in the solid state. The self-assembly properties of the new copolymers have been preliminary examined regarding their potential application as nanocarriers for pharmaceutical compounds.
This Thesis initially reports the ROP of w-pentadecalactone (PDL) using different amino-ended initiators and assisted by either organic or enzymatic catalysts. This method was then extended for the ROP of PDL using bisamino-ended poly(ethylene glycol) (PEG) for the preparation of poly(w-pentadecalactone)-b-poly(ethylene glycol)-b-poly(wpentadecalactone) [PPDLx-PEG-PPDLx] triblock copolymers. These amphiphilic ABA-type copolymers were able to selfassemble in water to form nanoparticles with diameters between 100 and 200 nm.
Hybrid copolymers of poly(ester-peptide) or poly(ether-ester-peptide) type exhibiting different architectures (e.g. diblock, triblock, graft or triblock/grafted) respectively, were then synthesized using as building blocks: poly(w-pentadecalactone), poly(globalide) (PGl), PEG as well as polypeptides derived from the L-glutamic acid (Glu), L-lysine (Lys), L-alanine (Ala) and L-phenylalanine (Phe) a-amino acids. The hybrid copolymers were synthesized through several stages depending on the desired architecture. The first stage in the preparation of these copolymers was the synthesis of macroinitiators from PDL or PGl containing either an amino group at the end of the chain or multiple amine groups along their polymeric chain. In the second stage, such macroinitiators were used to trigger the polymerization of the a-amino acid N-carboxyanhyrides (NCA) with the COOH group of L-glutamic acid and NH2 of L-lysine duly protected as g-benzyl-L-glutamate (BLG) and eNcarbobenzoxy-L-lysine (ZLL) respectively. Some copolymers containing BLG or ZLL units were treated with acids to render copolymers bearing the amino acids residues with their COOH or NH2 functionalities in the free form.
All of the synthesized copolymers were fully characterized through GPC and NMR spectroscopy. The thermal properties were studied by TGA and DSC techniques. The conformation adopted by the peptide-based copolymers in the solid-state was assessed by FTIR, and their crystalline structure was examined by X-ray diffraction using synchrotron radiation in most cases. The conformation in aqueous solution of water-soluble copolymers containing Glu or Lys residues in the free form was explored by circular dichroism.
The self-assembly behavior in aqueous medium of all the amphiphilic copolymers was investigated with the purpose of obtaining nanoparticles with the appropriated diameters required for their application as biomedical nanocarriers. The nanoparticles were duly characterized by light scattering and SEM and TEM microscopies. Block and graft copolymers were able to load doxorubicin and release it under pH control. Copolymers containing L-lysine were shown to be able of condensing DNA. The potential of these copolymers as DDS of anticancer drugs and vectors for transfection have been evidenced.Los polipéptidos o proteínas obtenidos de manera natural son considerados como polímeros altamente refinados. Cuando los polímeros sintéticos se unen a proteínas o polipéptidos, los sistemas bioconjugados que se obtienen pueden sinérgicamente combinar las propiedades de sus componentes individuales y mejorar las propias limitaciones que tienen por separado. La proteína o el elemento polipeptídico puede impartir propiedades bifuncionales al bioconjugado, mientras que el polímero sintético puede mejorar la estabilidad proteica, la solubilidad y la biocompatibilidad. Esta tesis está enfocada en el estudio de copolímeros híbridos basados en polipeptidos y polimacrolactonas. Copolímeros tipo bloque e injerto fueron sintetizados utilizando principalmente la polimerización por apertura de anillo y extensamente caracterizados tanto su estructura química, como su estructura en estado sólido. Las propiedades de auto-agregación de los nuevos copolímeros han sido anteriomente examinadas respecto a su potencial aplicación como nanotransportadores de compuestos farmacéuticos. Esta Tesis inicialmente reporta la homopolimerización de w-pentadecalactona (PDL) usando diferentes iniciadores aminoterminados mediante el uso de catalizadores tanto orgánicos como enzimáticos. Este se extiende a la ROP de PDL usando poli(etilén glicol) bisamino-terminado (PEG) para la preparar copolímeros tribloque poli(w-pentadecalactona)-b-poli(etilén glicol)-b-poli(w-pentadecalactona) [PPDLx-PEG-PPDLx]. Estos copolímeros de tipo ABA fueron capaces de auto-agregarse en agua para formar nanopartículas con diámetros entre 100 y 200 nm. Por otra parte, sistemas híbridos de tipo poli(éster-péptido) o poli(éter-éster-péptido) que presentan distintas arquitecturas (por ejemplo dibloque, tribloque, injerto, o tribloque-injertado) respectivamente, se sintetizaron utilizando como bloques de construcción derivados de macrolactonas (w-pentadecalactona), globalida) y a-amino ácidos (ácido L-glutámico (Glu), Llisina (Lys), L-alanina (Ala) y L-fenilalanina (Phe) así como poli(etien glicol) telequélico. Los copolímeros híbridos fueron sintetizados en varias etapas dependiendo de cuál fuese la arquitectura deseada. La primera etapa fue la preparación de los macroiniciadores a partir de PDL o PGl conteniendo en su estructura ya sea un grupo amino en el extremo de la cadena, o múltiples grupos aminos a lo largo de la cadena polimérica. En la segunda etapa, los macroiniciadores fueron utilizados en la polimerización de a-amino ácidos N-carboxianhídridos (NCA), con los grupos COOH del ácido L-glutámico y el grupo NH2 de la L-lisina apropiadamente protegidos como g-bencil-L-glutamato (BLG) y eN-carbobenzoxi-L-lisina (ZLL) respectivamente. Para los copolímeros que contienen bloques peptídicos de BLG o ZLL, las funcionalidades COOH o NH2 fueron regeneradas bajo condiciones ácidas, para producir así los copolímeros conteniendo el amino ácido en su forma libre. Todos los copolímeros sintetizados fueron completamente caracterizados mediante GPC y espectroscopia de RMN. Las propiedades térmicas fueron estudiadas por las técnicas de TGA y DSC. La conformación adoptada por los copolímeros en el estado sólido fue estudiada por FTIR, y su estructura cristalina fue analizada mediante difracción de rayos X usando radiación sincrotrón en la mayoría de los casos. La conformación en solución acuosa de los copolímeros solubles en agua, que contienen residuos de Glu o Lys, fue analizada por dicroísmo circular. Se estudió el comportamiento de todos los copolímeros para auto-agregarse en agua obteniéndose partículas con diámetros del orden nanométrico, como se demostró por DLS así como también por SEM y TEM, las cuales son apropiadas para ser aplicadas en biomedicina. Las nanopartículas de copolímeros dibloque y de injerto conteniendo ácido L-glutámico fueron capaces de incorporar doxorubicina y efectuar su liberación bajo control por medio del pH. Por otro lado, los copolímeros dibloque y de injerto con bloques conteniendo L-lisina mostraron la habilidad de condensar el ADN, demostrando así su potencial uso como vectores en transfección.
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Dumont, Camille. "Nanovecteurs lipidiques pour la délivrance orale de peptides." Thesis, Lyon, 2020. http://www.theses.fr/2020LYSE1022.
Повний текст джерелаАнотація:
Les peptides thérapeutiques peuvent traiter de nombreuses pathologies de manière efficace et sélective. Leur biodisponibilité orale est limitée par une forte dégradation liée à l’action de protéases dans le lumen intestinal et par une faible absorption par la barrière intestinale. Nous avons évalué la capacité des nanoparticules lipidiques solides (SLN) et des vecteurs lipidiques nanostructurés (NLC) à augmenter la biodisponibilité orale d’un peptide modèle : le Leuprolide (LEU). L’augmentation de sa lipophilie par formation d’une paire d’ions hydrophobe (HIP) avec le docusate permet d’augmenter significativement le taux d’encapsulation du LEU dans les nanovecteurs. Ceux-ci sont obtenus par homogénéisation haute pression avec une taille de 120 nm et une structure en plaquettes. Malgré leur stabilité dans les milieux gastro-intestinaux simulés, une libération importante de l’actif est observée dans le milieu intestinal à jeun. Vis-à-vis de la dégradation protéolytique, les NLC montrent une protection significative du LEU en présence de trypsine. L’évaluation du passage intestinal sur des monocouches de Caco-2 (modèle entérocyte) et de Caco-2/HT29-MTX (modèle sécrétant des mucines) révèle une internalisation des nanovecteurs mais aucune amélioration de l’absorption. En effet, la morphologie en plaquettes des SLN et NLC associée à la faible stabilité de l’HIP dans le milieu provoquent une libération importante du LEU, annulant la capacité de transport des nanovecteurs à travers la barrière intestinale. Il convient d’améliorer la stabilité de la hydrophobisation pour augmenter la biodisponibilité orale des peptides via l’encapsulation dans des nanovecteurs lipidiques solidesTherapeutic peptides are able to treat a wide variety of diseases with selective and potent action. Their oral bioavailability is strongly limited by an important proteolytic activity in the intestinal lumen and poor permeation across the intestinal border. We have evaluated the capacity of Solid Lipid Nanoparticles (SLN) and Nanostructured Lipid carriers (NLC) to overcome both oral bioavailability limiting aspects, using Leuprolide (LEU) as model peptide. Lipidization of LEU by formation of a Hydrophobic Ion Pair (HIP) with docusate enables a significant increase of peptide encapsulation efficiency in both SLN and NLC. The nanocarriers, obtained by high pressure homogenization, measured 120 nm and were stable in simulated gastro-intestinal fluids. However, due to particles platelet-shape, an important quantity of LEU is released in simulated fasted state intestinal fluid. Regarding the protective effect towards proteolytic degradation, only NLC maintain LEU integrity in presence of trypsin. Intestinal transport, evaluated on Caco-2 (enterocyte-like model) and Caco-2/HT29-MTX (mucin-secreting model) monolayers, show nanocarriers internalization by enterocytes but no improvement of LEU permeability. Indeed, the combination of nanoparticles platelet-shape with the poor stability of the HIP in the transport medium induces a high burst release of the peptide, limiting nanoparticles capacity to transport LEU across the intestinal border. Stability of peptide lipidization needs to be improved to withstand biorelevant medium to benefit from the advantages of encapsulation in solid lipid nanocarriers and consequently improve their oral bioavailability
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Kaur, Kuljeet. "Synthesis, evaluation, and applications of hydrogen sulfide-releasing supramolecular materials." Diss., Virginia Tech, 2020. http://hdl.handle.net/10919/104204.
Повний текст джерелаАнотація:
H2S is a biologically relevant signaling gas that is endogenously produced throughout the body. The (patho)physiological roles of H2S have led researchers to develop various compounds that decompose to release H2S (H2S donors) for exogenous H2S administration. However, many small molecule H2S donors suffer from poor solubility, low stability, and lack of control over H2S release rates. As a result, there has been an increasing interest in utilizing supramolecular materials for exogenous H2S delivery.
With growing potential applications of supramolecular H2S-releasing materials, it is important to explore their properties, e.g., solubility and stability under physiological conditions. We investigated the hydrolytic stability over a range of pH conditions of a series of peptides containing H2S-releasing S-aroylthiooximes (SATOs). The SATO-peptides showed structure–reactivity relationships with SATO ring substituents playing a crucial role in hydrolysis rates. Electron-donating substituents accelerate the rate of hydrolysis while electron-withdrawing substituents slows it down. We also explored their hydrolysis mechanisms at different pH values.
SATO-peptides were then used to form hydrogels at 1 wt.% triggered by Ca2+. Hydrogels can be applied directly at a site of interest, potentially improving the efficacy of H2S compared with small molecule donors that diffuse away. We developed a H2S-releasing hydrogel capable of slowly releasing H2S locally to test its efficacy on intimal hyperplasia. The hydrogel delivered H2S over the period of several hours and inhibited the proliferation of human vascular smooth muscle cells (VSMCs) significantly better than fast-releasing NaSH salts. This study shows a promising application of supramolecular H2S-releasing materials over widely used sulfide salts.
The macroscopic properties of peptide hydrogels could be further modulated to achieve additional control over the H2S release properties. We synthesized a series of peptide hydrogels incorporating different linker segments to study their effects on hydrogelation properties. Most peptides formed hydrogels but with significantly different rheological behavior. We found that peptides with flexible linkers such as ethyl, substituted O-methylene, and others, formed stronger hydrogels compared to those with more rigid linkers. Interestingly, we found that stiffer hydrogels released H2S over longer periods than softer ones by retarding the diffusion of a thiol trigger, likely due to bulk degradation of the soft gels but surface erosion of the stiff gels as they release H2S.Doctor of Philosophy
H2S has long been known as a foul smelling gas until it was discovered that it is endogenously produced throughout the body and plays many (patho)physiological roles. Therapeutic benefits of H2S have led researchers to develop various compounds that release H2S (H2S donors) for exogenous H2S administration. However, many small molecule H2S donors suffer from poor solubility, low stability, and unregulated H2S release. As a result, there has been an increasing interest in utilizing materials for exogenous H2S delivery. With growing potential applications of H2S-releasing materials, it is important to explore their properties, e.g., solubility and stability under physiological conditions. We investigated the stability of a series of peptides containing H2S-releasing S-aroylthiooximes (SATOs) over a range of pH conditions. The stability of SATO-peptides was dependent on chemical makeup of the SATO part of the peptides. We also explored their hydrolysis mechanisms at different pH values. SATO-peptides were then used to form hydrogels triggered by Ca2+. Hydrogels can be applied directly at a site of interest, potentially improving the efficacy of H2S compared with small molecule donors that diffuse away. We developed a H2S-releasing hydrogel capable of slowly releasing H2S locally to test its efficacy on intimal hyperplasia. The hydrogel delivered H2S over the period of several hours and inhibited the proliferation of human vascular smooth muscle cells (VSMCs) significantly better than fast-releasing NaSH salts. This study shows a promising application of supramolecular H2S-releasing materials over widely used sulfide salts. The macroscopic properties of peptide hydrogels could be further modulated to achieve additional control over the H2S release properties. We synthesized a series of peptide hydrogels incorporating different linker segments to study their effects on hydrogelation properties. Most peptides formed weak to strong hydrogels with calcium chloride.We found that peptides with flexible linkers formed stronger hydrogels compared to those with more rigid linkers. Interestingly, we found that stiffer hydrogels released H2S over longer periods than softer ones.
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Cao, Yichen. "APPLICATION OF LINEAR FREE ENERGY RELATIONSHIPS IN THE PREDICTION OF TRIGLYCERIDE/WATER PARTITION COEFFICIENTS AND LIPID BILAYER PERMEABILITY COEFFICIENTS OF SMALL ORGANIC MOLECULES AND PEPTIDES." UKnowledge, 2008. http://uknowledge.uky.edu/gradschool_diss/655.
Повний текст джерелаАнотація:
Computational methods such as linear free energy relationships (LFERs) offer a useful high-throughput solution to quickly evaluate drug developability, e.g. membrane permeability, organic solvent/water partition coefficients, and solubility. LFERs typically assume the contribution of structural components/functional groups to the overall properties of a given molecule to be constant and independent. This dissertation describes a series of studies in which linear free energy relationships were developed to predict solvation of small organic molecules in lipid formulations, specifically, triglyceride containing solvents and phospholipid-based liposomes. The formation of intermolecular HBs in triglyceride solvents (homogenous with H-bond accepting ability) and intramolecular HBs within the bilayer barrier domain (hydrocarbon-like) proved to be the major factors to consider in developing LFERs to account for the increased oil/water partition coefficients and enhanced bilayer permeability of small organic molecules.
The triglyceride solvent/water partition coefficients of a series of model compounds varying in polarity and H-bond donating/accepting capability were used to establish a correlation between the solvent descriptors and the ester concentration in these solvents using the Abraham LFER approach. The LFER analyses showed that the descriptors representing the polarizability and H-bond basicity of the solvents vary systematically with the ester concentration.
A fragment-based LFER to predict membrane permeability or 1,9- decadiene/water partition coefficients of small organic molecules including small peptides was systematically constructed using a total of 47 compounds. Significant nonadditivity was observed in peptides in that the contribution of the peptide backbone amide to the apparent transfer free energy from water into the bilayer barrier domain is considerably smaller than that of a “well-isolated” amide and greatly affected by adjacent polar substituents on the C-termini.
In order to explain the phenomenon of nonadditivity, the formation of intramolecular HBs and inductive effects of neighboring polar groups on backbone amide, were investigated using FTIR and MD simulations. Both spectroscopic and computational results provided supportive evidence for the hypothesis that the formation of intramolecular HBs in peptides is the main reason for the observed nonadditivity of Δ(ΔG°)-CONH-. The MD simulation results showed that the inductive effect of neighboring groups is not as important as the effect of intramolecular HBs.
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Mazza, Mariarosa. "Peptide nanofibres for drug delivery." Thesis, University College London (University of London), 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.553693.
Повний текст джерелаАнотація:
It is possible that peptides and proteins may be used to treat a wide range of Central Nervous System diseases if these molecules were able to cross the blood brain barrier (BBB). Currently these molecules do not cross the BBB due to their hydrophilic nature and large size. The aim of this work was to investigate the therapeutic applicability of peptide nanofibres as a new peptide brain delivery system. We hypothesise that hydrophilic peptides, when made lipophilic by attaching an acyl chain via a cleavable ester linkage, are able to cross the blood brain barrier and that the resulting lipidic peptides nanofibres assist in the delivery of these molecules to the brain. Dalargin, a neuropeptide and hexapeptide analogue of Leu-enkephalin that is unable to cross the blood brain barrier, was chosen as model drug; on direct injection into the brain, dalargin acts on brain opioid receptors, resulting in analgesia. An amphiphilic derivative of dalargin, palmitoyl dalargin (pDal) was synthesized which self assembled into high-axial-ratio nanostructures in aqueous environments. We have investigated the physicochemical interactions that control to the formation of peptide nanofibres and found that hydrophobic interactions as well as the formation of amino acid ~-sheets are the main drivers of self-assembly. Brain peptide delivery was assessed following intravenous administration of formulations containing pDal nanofibres, nanofibres prepared from pDal and a chitosan amphiphile - quaternary ammonium palmitoyl glycol chitosan (GCPQA) and dalargin (in the absence and presence of GCPQA). While the administration of control samples of dalargin did not result in dalargin being detected in any tissues (only the primary metabolite was detected), pDal was clearly detected in the brain both in the presence and absence of GCPQA. Furthermore only animals administered with pDal experienced analgesia when assayed using the tail flick test. We conclude that peptide nanofibres offer a unique method for delivering hydrophilic peptides across the blood brain barrier.
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Wang, Yan. "Peptide-drug conjugate for Her2-targeted drug delivery." Scholarly Commons, 2018. https://scholarlycommons.pacific.edu/uop_etds/3567.
Повний текст джерелаАнотація:
Recent strategies for anticancer drug design have been focused on utilizing antibody as a drug or targeted moiety for targeted drug delivery. Antibody−drug conjugates (ADCs) have become a promising new class of targeted therapeutic agents for treatment of cancer. ADCs are designed to preferentially direct a cytotoxic drug to a cell-surface antigen recognized by an antibody. However, there are some challenges in developing ADCs, such as limited solid tumor penetration, high manufacturing costs and antibody-drug stoichiometry. Smaller molecules such as peptides have been shown to specifically bind to cancer related targets. These peptides can be used to form peptide-drug conjugates (PDCs) to overcome above-mentioned drawbacks presented by ADCs.
In this study, it was hypothesized that novel synthesized PDCs can be a strategy for breast cancer therapy. HER2 specific binding peptides, MARAKE and MARSGL, were modified by addition of a cysteine at C-terminus. The modified peptides were coupled with monomethylauristatin E (MMAE) by using maleimidocaproyl (MC) as a non-cleavable linker to form peptide-drug conjugates (YW1, YW2) and maleimidocaproyl-valine-citrulline (MC-VC) as a cleavable linker to form peptide-drug conjugates (YW3 and YW4). The peptides, peptide-drug conjugates and MC-MMAE, MC-VC-MMAE were characterized using ESI-MS and purified by using high-performance liquid chromatography (HPLC). Cellular uptake study was performed to determine binding specificity and internalization of two HER2 specific peptides and cysteine-modified peptides (MARAKEC, MARSGLC). In vitro cell viability assay was conducted to assess the cytotoxicity and determine the targeting specificity as well as the potency of the peptide-drug conjugates.
The purity of each compound was greater than 90%. Internalization of both HER2 specific binding peptides and cysteine-modified peptides were significantly higher than random peptides in HER2 over-expressed cell lines, MDA-MB361 and ZR75, while negligible uptake in HER2 negative cell line, HEK293. MC linked PDCs showed similar cytotoxicity as peptide in all cell lines; while MC-VC linked PDCs have higher cytotoxicity than MMAE in HER2 positive cell line and significant lower cytotoxicity than MMAE in normal cell line HEK293. However, PDCs with MC link do not show significant difference in cytotoxicity compared to the peptide in all cell lines.
In conclusion, specificity of HER2 binding for both peptides was preserved after modification with cysteine. The derivation of MMAE to link drug and peptide played a crucial role in the anticancer activity. Peptide-MMAE conjugates with cleavable linker showed a promising targeting capability for delivery of MMAE to HER2 overexpressed cancer cells.
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Penchala, Sravan C. "Characterization of AG10, a potent stabilizer of transthyretin, and its application in enhancing in vivo half-life of therapeutic peptides." Scholarly Commons, 2016. https://scholarlycommons.pacific.edu/uop_etds/130.
Повний текст джерелаАнотація:
The misassembly of soluble proteins into toxic aggregates, including amyloid fibrils, underlies a large number of human degenerative diseases. Cardiac amyloidoses, which are most commonly caused by aggregation of Immunoglobulin (Ig) light chains or transthyretin (TTR) in the cardiac interstitium and conducting system, represent an important and often underdiagnosed cause of heart failure. Two types of TTR-associated amyloid cardiomyopathies are clinically important. The Val122Ile (V122I) mutation, which alters the kinetic stability of TTR and affects 3% to 4% of African Americans, can lead to development of familial amyloid cardiomyopathy. In addition, aggregation of WT TTR in individuals older than age 65 years causes senile systemic amyloidosis. TTR-mediated amyloid cardiomyopathies are chronic and progressive conditions that lead to arrhythmias, biventricular heart failure, and death. As no Food and Drug Administration-approved drugs are currently available for treatment of these diseases, the development of therapeutic agents that prevent TTR-mediated cardiotoxicity is desired. Here, we report the characterization of AG10 , a potent and selective kinetic stabilizer of TTR. AG10 prevents dissociation of V122I-TTR in serum samples obtained from patients with familial amyloid cardiomyopathy. In contrast to other TTR stabilizers currently in clinical trials, AG10 stabilizes V122I- and WT-TTR equally well and also exceeds their efficacy to stabilize WT and mutant TTR in whole serum. Crystallographic studies of AG10 bound to V122I-TTR give valuable insights into how AG10 achieves such effective kinetic stabilization of TTR, which will also aid in designing better TTR stabilizers. The oral bioavailability of AG10 , combined with additional desirable drug-like features, makes it a very promising candidate to treat TTR amyloid cardiomyopathy. The second part of the thesis discusses harnessing TTR as a platform to enhance in vivo half-life of therapeutic peptides. The tremendous therapeutic potential of peptides has not yet been realized, mainly owing to their short in vivo half-life. Although conjugation to macromolecules has been a mainstay approach for enhancing protein half-life, the steric hindrance of macromolecules often harms the binding of peptides to target receptors, compromising the in vivo efficacy. Here we report a new strategy for enhancing the in vivo half-life of a model peptide Gonadotropin Releasing Hormone (GnRH) and its analog GnRH-A without compromising their potency. Apart from GnRH, we have used other peptides to study their proteolytic stability in vitro . Our approach involves endowing peptides with a small molecule that binds reversibly to the serum protein transthyretin. Although there are a few molecules that bind albumin reversibly, we are unaware of designed small molecules that reversibly bind other serum proteins and are used for half-life extension in vivo . We show here that our strategy was effective in enhancing the half-life of an agonist for GnRH receptor while maintaining its binding affinity, which was translated into superior in vivo efficacy.
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Soane, Robert J. "Bioadhesive polymers as intranasal drug delivery systems for peptide and protein drugs." Thesis, University of Nottingham, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.298078.
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Kansara, Viral Mitra Ashim K. "Ocular delivery of peptide ganciclovir prodrugs following subconjunctival injection evaluation of episcleral drug delivery approach /." Diss., UMK access, 2007.
Знайти повний текст джерелаАнотація:
Thesis (Ph. D.)--School of Pharmacy. University of Missouri--Kansas City, 2007."A dissertation in pharmaceutical sciences and pharmacology." Advisor: Ashim K. Mitra. Typescript. Vita. Title from "catalog record" of the print edition Description based on contents viewed May 23, 2008. Includes bibliographical references (leaves 210-225). Online version of the print edition.
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Wilson, Sarah, and n/a. "Vaccine peptide delivery by virus particles." University of Otago. Department of Microbiology & Immunology, 2007. http://adt.otago.ac.nz./public/adt-NZDU20080131.161222.
Повний текст джерелаАнотація:
Vaccination with immunogenic peptides offers a safe and specific way of inducing protection against pathogens, however as of yet there are no peptide-based vaccines available. The limitations on the therapeutic use of peptides are due to their poor immunogenicity and short life span in vivo. Peptide delivery systems act to circumvent these issues. The aims of this research were to investigate the ability of virus-like particles (VLP) from Rabbit haemmorhagic disease virus (RHDV) to deliver immunogenic peptides, to characterize the immune response to these particles, and to investigate whether baculovirus could also act as a delivery system. The vaccine peptides HAT (representing a T helper cell epitope) and HAB (representing the major B cell epitope) derived from the haemagglutinin antigen of influenza virus A/PR/8/34 were used as a model to investigate the ability of these virus particles to act as delivery vehicles to the immune system.
A scheme for the production and purification of RHDV VLP was established. Expression of the capsid protein from RHDV in a serum-free recombinant baculovirus system using suspension cultures of up to 200 ml, and separation by isopycnic centrifugation on cesium chloride gradients led to high yields of purified RHDV VLP. Up to 20 mg of pure VLP could be obtained from an 800 ml culture of insect cells infected with recombinant baculovirus.
In vitro testing revealed that RHDV VLP carrying the peptide HAT as a genetic fusion were processed by dendritic cells (DC), and that this peptide could be presented to induce activation of T cells. However, the purified RHDV VLP alone were not able to induce significant upregulation of cell activation markers CD40, CD86, and CD80.
A preliminary in vivo study revealed that when RHDV VLP carrying the HAT peptide were delivered by an intraperitoneal injection in the absence of adjuvant, the immune response to the peptide was weak, therefore the route of delivery and the use of immune adjuvants with the VLP were optimised.
Five different routes of delivery and two different immune adjuvants were compared. VLP were delivered through subcutaneous, intraperitoneal, transcutaneous, intramuscular and intranasal routes. Delivery of the VLP through each of these routes resulted in potent serum antibody responses. However, the strongest antibody responses were elicited when the VLP were delivered through the intraperitoneal or intranasal routes. Of these two routes, intranasal delivery gave the best mucosal responses at the lung surface, and was therefore chosen as the route of delivery for subsequent trials.
CpG DNA and the wild-type baculovirus Autographa californica nucleopolyhedrovirus (AcMNPV) were tested as adjuvants for the RHDV VLP. These two adjuvants gave similar results, both acting to enhance a T[H]1 type response against the VLP, characterized by significantly increased levels of serum IgG2a and enhanced IFN-γ production. Two approaches were then tested: using the RHDV VLP as a peptide carrier with a CpG adjuvant, and using baculovirus particles directly as self-adjuvanting carriers for vaccine peptides.
HAT and HAB peptides were chemically coupled to RHDV VLP. Mice that were vaccinated with these VLP mixed with a CpG adjuvant were able to raise low levels of specific antibody in the serum against influenza, and specific IgA against influenza was detected in the lung. These results indicated that, though the immune responses raised were modest, the RHDV VLP was able to deliver the vaccine peptides to the immune system.
HAT and HAB peptides were chemically coupled to baculovirus particles. When mice were immunized with the baculovirus carrying the vaccine peptides, they raised significant levels of IgG1 (p<0.001) and IgG2a (p<0.05) against influenza in the serum, when compared to peptide delivered alone. A significant level of influenza-specific IgA was also detected in the lung at 10 ng/ml in the mice that received the baculovirus coupled with peptide. Analysis of splenocyte cytokines showed that these mice also responded to restimulation with IFN-γ production at around 100 pg/ml.
This research revealed that RHDV VLP are able to act as carriers for vaccine peptides, however there are some limitations to their use with the HAT and HAB model peptides. It also showed that baculovirus can be rapidly modified to carry vaccine peptides by chemical conjugation, and that these peptides can be delivered to induce specific systemic and mucosal immunity, raising both B cell and cell mediated responses. Both virus particles have potential as components for new strategies for vaccination.
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Kim, Yeu Chun. "Transdermal Drug Delivery Enhanced by Magainin Peptide." Diss., Georgia Institute of Technology, 2007. http://hdl.handle.net/1853/19738.
Повний текст джерелаАнотація:
The world-wide transdermal drug delivery market is quite large, but only a small number of agents have FDA approval. The primary reason for such limited development is the difficulty in permeating the stratum corneum layer of human skin.
In our study, we developed a novel percutaneous delivery enhancing approach. Magainin peptide was previously shown to disrupt vesicles from stratum corneum lipid components and this ability of magainin allows us to propose that magainin can increase skin permeability. Therefore, we tested the hypothesis that magainin, a pore-forming peptide, can increase skin permeability by disrupting stratum corneum lipid structure and that magainin¡¯s enhancement requires co-administration of a surfactant chemical enhancer to increase magainin penetration into the skin. In support of these hypotheses, synergistic enhancement of transdermal permeation can be observed with magainin peptide in combination of N-lauroyl sarcosine (NLS) in 50% ethanol-PBS solution. The exposure to NLS in 50% ethanol solution increased in vitro skin permeability to fluorescein 15 fold and the addition of magainin synergistically increased skin permeability 47 fold. In contrast, skin permeability was unaffected by exposure to magainin without co-enhancement by NLS-ethanol.
To elucidate the mechanism of this synergistic effect, several characterization methods such as differential scanning calorimetry, Fourier transform infrared spectroscopy, and X-ray diffraction were applied. These analyses showed that NLS-ethanol disrupted stratum corneum lipid structure and that the combination of magainin and NLS-ethanol disrupted stratum corneum lipids even further. Furthermore, confocal microscopy showed that magainin in the presence of NLS-ethanol penetrated deeply and extensively into stratum corneum, whereas magainin alone penetrated poorly into the skin. Together, these data suggest that NLS-ethanol increased magainin penetration into stratum corneum, which further increased stratum corneum lipid disruption and skin permeability.
Finally, skin permeability was enhanced by changing the charge of magainin peptide via pH change. We modulated pH from 5 to 11 to change the magainin charge from positive to neutral, which decreased skin permeability to a negatively charged fluorescein and increased skin permeability to a positively charged granisetron. This suggests that an attractive interaction between the drug and magainin peptide improves transdermal flux.
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Doyen, Camille. "Utilisation de la RMN pour la caractérisation structurale et cinétique d'associations peptide-liposome comme aide à la conception de formulation." Thesis, université Paris-Saclay, 2020. http://www.theses.fr/2020UPASS110.
Повний текст джерелаАнотація:
L’encapsulation de principes actifs (PA) dans des liposomes est utilisée dans de nombreux domaines tels que les industries pharmaceutiques et cosmétiques. Les liposomes sont des systèmes d’administration de médicaments utilisés pour leur relargage contrôlé des PA. Pour augmenter l’efficacité de peptides comme PA, nous cherchons à optimiser des liposomes en jouant à la fois sur leur composition et la structure des peptides. Les paramètres à améliorer sont leurs interactions, l’efficacité d’encapsulation et la cinétique de relargage. Pour atteindre cet objectif, j’ai évalué l’intérêt de la spectroscopie par Résonance Magnétique Nucléaire (RMN) pour caractériser les peptides, les liposomes et leurs comportements pendant le relargage. Les peptides utilisés dans cette étude sont dérivés de l’apeline, qui a un intérêt pour la régulation homéostatique du système cardiovasculaire. Les structures des liposomes et des peptides ainsi que leurs interactions ont été étudiées par RMN ¹H et ³¹P et par cryo-EM. J’ai montré que les méthodes de diffusion par RMN, en s’appuyant sur la taille apparente des molécules, permettent de différencier les compartiments internes et externes des liposomes et de suivre les cinétiques in situ en temps réel de relargage de peptide, sans perturber le processus. Les cinétiques de relargage ont aussi été quantifiées par intégration spectrale de spectres RMN ¹H. J’ai aussi montré que la méthode de préparation des liposomes avait un impact sur leur structure, leur cinétique de relargage et leurs interactions avec des peptides. L’addition d’une chaîne lipidique augmente les interactions avec les liposomes, mais la longueur et le type de chaîne induisent peu de différences. Les outils de RMN mis en place pourront être étendus à d’autres PA et systèmes d’administration pour des applications pharmaceutiques et cosmétiquesThe encapsulation of active ingredients (AI) in liposomes is used in several domains such as pharmaceutical and cosmetic industries. Liposomes are drug delivery systems (DDS) used for a controlled release of AIs. To increase the efficiency of peptide drugs, I aim at designing optimized peptide/liposomes formulation by playing both on their composition and peptide structure. Potential parameters to be improved are their interactions, encapsulation efficiency and release kinetics. To reach this goal, I explored the potentiality of Nuclear Magnetic Resonance (NMR) spectroscopy to characterize peptides, liposomes and their behavior during release. The AIs used in this study are apelin-derived peptides that are of interest for homeostasis regulation of the cardiovascular system. Liposome and peptide structures as well as their interactions were characterized by ¹H and ³¹P NMR and cryo-EM. I showed that diffusion NMR methods that report on the apparent size of molecules can discriminate between the inner and the outer space of liposomes and for release quantification in-situ and in real-time without perturbing the process. Moreover, ¹H NMR spectra were used to monitor and quantify peptide release kinetics by spectral integration. I showed that the preparation method of liposomes drastically impacts their structure, release kinetics and interactions with peptides. Addition of a lipid chain increases the interaction with the liposomes, but the type and length of the chain induce only few differences. This approach could certainly be extended to other AIs and DDSs used for pharmaceutical and cosmetic applications
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Haraszti, Reka A. "Engineered Exosomes for Delivery of Therapeutic siRNAs to Neurons." eScholarship@UMMS, 2018. https://escholarship.umassmed.edu/gsbs_diss/971.
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Extracellular vesicles (EVs), exosomes and microvesicles, transfer endogenous RNAs between neurons over short and long distances. We have explored EVs for siRNA delivery to brain. (1) We optimized siRNA chemical modifications and siRNA conjugation to lipids for EV-mediated delivery. (2) We developed a GMP-compatible, scalable method to manufacture active EVs in bulk. (3) We characterized lipid and protein content of EVs in detail. (4) We established how protein and lipid composition relates to siRNA delivering activity of EVs, and we reverse engineered natural exosomes (small EVs) into artificial exosomes based on these data.
We established that cholesterol-conjugated siRNAs passively associate to EV membrane and can be productively delivered to target neurons. We extensively characterized this loading process and optimized exosome-to-siRNA ratios for loading. We found that chemical stabilization of 5'-phosphate with 5'-E-vinylphosphonate and chemical stabilization of all nucleotides with 2'-O-methyl and 2'-fluoro increases the accumulation of siRNA and the level of mRNA silencing in target cells. Therefore, we recommend using fully modified siRNAs for lipid-mediated loading to EVs. Later, we identified that α-tocopherol-succinate (vitamin E) conjugation to siRNA increases productive loading to exosomes compared to originally described cholesterol.
Low EV yield has been a rate-limiting factor in preclinical development of the EV technology. We developed a scalable EV manufacturing process based on three-dimensional, xenofree culture of mesenchymal stem cells and concentration of EVs from conditioned media using tangential flow filtration. This process yields exosomes more efficient at siRNA delivery than exosomes isolated via differential ultracentrifugation from two-dimensional cultures of the same cells.
In-depth characterization of EV content is required for quality control of EV preparations as well as understanding composition–activity relationship of EVs. We have generated mass-spectrometry data on more than 3000 proteins and more than 2000 lipid species detected in exosomes (small EVs) and microvesicles (large EVs) isolated from five different producer cells: two cell lines (U87 and Huh7) and three mesenchymal stem cell types (derived from bone marrow, adipose tissue and umbilical cord Wharton’s jelly). These data represent an indispensable resource for the community. Furthermore, relating composition change to activity change of EVs isolated from cells upon serum deprivation allowed us to identify essential components of siRNA-delivering exosomes. Based on these data we reverse engineered natural exosomes into artificial exosomes consisting of dioleoyl-phosphatidylcholine, cholesterol, dilysocardiolipin, Rab7, AHSG and Desmoplakin. These artificial exosomes reproduced efficient siRNA delivery of natural exosomes both in vitro and in vivo. Artificial exosomes may facilitate manufacturing, quality control and cargo loading challenge that currently impede the therapeutic EV field.
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Danton, Malcolm. "Peptide synthesis : evaluation of lipidic A-amino acids as drug and peptide delivery systems." Thesis, University College London (University of London), 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.339201.
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Flinn, Nicholas Sean. "A lipidic amino acid based system for peptide delivery and enhancing peptide immunogenicity." Thesis, University College London (University of London), 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.244682.
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Kenworthy, Sarah. "The use of synthetic polymers in oral peptide delivery." Thesis, Keele University, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.361831.
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Larnaudie, Sophie. "Supramolecular cyclic peptide-polymer nanotubes as drug delivery vectors." Thesis, University of Warwick, 2017. http://wrap.warwick.ac.uk/96206/.
Повний текст джерелаАнотація:
The objective of this thesis is to develop a range of polymeric nanotubes based on self-assembling cyclic peptides suitable to be used as drug delivery systems, and to investigate their behaviour in vitro and in vivo. The interest for cylindrical structures in a drug delivery context arises from their reported longer circulation times, and enhanced tumour accumulation in vivo compared to spherical nanoparticles. Moreover, supramolecular systems have attracted a lot of attention thanks to their versatility and potential ability to facilitate clearance. The design of polymeric nanotubes constructed around a cyclic peptide scaffold is described, and various systems are developed. Firstly, the two main synthetic routes (grafting-to and grafting-from) yielding peptide-polymer conjugates are compared in a systematic study, which shows that the two approaches present distinct advantages, and are complementary in nature. This information is then used to design cyclic peptide conjugates specifically directed to drug delivery, using a polymer that combines biocompatible properties and functional handles. Analysis of their self-assembly in solution confirms the cylindrical shape of the obtained supramolecular structures, and a study of their behaviour in vitro and in vivo establishes their potential as delivery systems. Subsequently, the complexation of a highly potent organometallic anticancer agent is described. In vitro studies determined that the use of the nanotubes leads to higher potency and enhanced selectivity towards cancer cells. Finally, a core-shell system designed for drug encapsulation and subsequent pH-triggered release is presented. This approach relies on the use of an amphiphilic and pH responsive system, which in addition confers more stability to the obtained nanotubes. The work presented in this thesis provides a bottom-up approach in the design of novel self-assembled cyclic peptide nanotubes highly tuned for drug delivery applications.
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Grandolfi, George P. "Physicochemical studies of carrier systems for peptide drug delivery /." The Ohio State University, 1991. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487758680160372.
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Marshall, Neil J. "Antibacterial agents designed to exploit peptide transport systems." Thesis, Bangor University, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.262012.
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