Thesis (Ph. D.)--University of Washington, 2004. / Vita. Includes bibliographical references (leaves 127-141).

Thesis (Ph. D.)--Rutgers University, 2007. / "Graduate Program in Chemistry and Chemical Biology." Includes bibliographical references.

Thesis (Ph. D.)--University of Washington, 2007. / Vita. Includes bibliographical references (leaves 88-97).

Lipossomas (LUV) são estruturas compostas por uma bicamada lipídica que se organizam de forma semelhante a vesículas, contendo um compartimento aquoso em seu interior. Têm sido avaliados como potenciais carreadores de fármacos. No entanto, após sua administração, in vivo, opsoninas do soro adsorvem-se em sua superfície contribuindo para que o sistema fagocitário mononuclear (SFM) reconheça essas partículas, favorecendo sua remoção da circulação. O sistema complemento (SC) parece ter papel importante neste processo, principalmente por gerar fragmentos ativos do componente C3 (C3b/iC3b) que se depositam nas vesículas lipossomais e são reconhecidos por receptores do complemento presentes, por exemplo, nos polimorfonucleares. Antioxidantes, como a quercetina, têm demonstrado importantes e benéficos efeitos sobre a saúde humana, porém sua baixa solubilidade em água e biodisponibilidade limitam seu uso. Assim, o desenvolvimento apropriado de carreadores de flavonoides seria de grande importância para sua aplicabilidade in vivo. O objetivo do presente trabalho é avaliar a ativação das proteínas do SC por lipossomas compostos de fosfatidilcolina de soja e colesterol (PC:CHOL) ou colesteril-etil-éter (PC:CHOL-OET), contendo ou não quercetina. O consumo das vias clássica (VC) e alternativa (VA) provocado pelas diferentes vesículas foi analisado por ensaio hemolítico e a quantificação de iC3b e anticorpos naturais (IgG e IgM) na superfície dessas partículas foi realizada através de kits de ELISA. A ativação de C3 por vesículas contendo ou não quercetina foi avaliada por imunoeletroforese bidimensional (IEF). Os resultados mostram que lipossomas vazios, compostos por grande quantidade de colesterol, consomem mais os componentes do complemento para ambas as vias, VC e VA. Ainda, a substituição de colesterol por colesteril-etil éter reduziu o consumo das duas vias, mas a ativação do SC ainda é dependente da quantidade deste composto. A incorporação de quercetina não alterou o consumo de ambas as vias. O depósito de iC3b, IgG ou IgM nas vesículas compostas de PC:CHOL-OET na proporção de massa 3:1 foi o menor comparado aos demais. A IEF mostrou que vesículas PC:CHOL vazias induzem maior clivagem de C3 em relação às vesículas PC:CHOL-OET. Ainda, a incorporação de quercetina reduz a conversão de C3 em seus fragmentos. Essas observações sugerem que a preparação lipossomal PC:CHOL-OET em proporção de massa 3:1 parece ser a mais adequada para dar continuidade aos estudos que deverão culminar na tentativa de utilizá-la como carreadora de quercetina para administração in vivo / Liposomes (LUV) are structures composed by lipid bilayer that are organized similarly to vesicles, containing an aqueous compartment inside. They have been evaluated as potential drug carriers, however, after in vivo administration, serum opsonins are adsorb on the surface, contributing to their clearance from the circulation by mononuclear phagocytes system (MPS). The complement system (CS) seems to play an important role in this process, mainly to generate active fragments of the C3 component (C3b/iC3b) that are deposited in the liposomal vesicles and are recognized by complement receptors present, for example, in polymorphonuclear cells. Antioxidants such as quercetin have demonstrated significant and beneficial effects on human health, but its low water solubility and bioavailability limit their use. Thus, the proper development of flavonoids carriers would be of great importance to its applicability in vivo. The objective of this study is to evaluate the activation of SC proteins by liposomes composed of soy phosphatidylcholine and cholesterol (PC: CHOL) or cholesteryl ethyl ether (PC: CHOL-OET), with or without quercetin. The consumption of the classical (CP) and alternative pathway (AP) caused by the different vesicles was analyzed by hemolytic assay and quantification of iC3b and natural antibodies (IgG and IgM) on the surface of these particles was performed using ELISA kits. The activation of C3 by vesicles with or without quercetin was assessed by two-dimensional immunoelectrophoresis (IEF). The results show that empty liposomes, composed of large amounts of cholesterol, consume more CS components in both pathways, CP and AP. Moreover the replacement of cholesterol by cholesteryl ethyl ether reduced the consumption of both pathways, but the activation of the SC is still dependent on the amount of the compound. The incorporation of quercetin did not alter the consumption of both pathways. The deposition of iC3b, IgG or IgM in vesicles composed of PC: CHOL-OET at mass ratio of 3:1 was the lowest compared to the others. The IEF showed that empty vesicles of PC:CHOL induce less cleavage of C3 in relation to vesicles of PC: CHOL-OET. In addition, the incorporation of quercetin reduces the conversion of C3 into its fragments. These observation suggest that the liposomes PC:CHOL at mass ratio 3:1 seems to be the most appropriate to continue the studies that could culminate in an attempt to use it as a carrier to administrate quercetin in vivo

Orientador: Anita Jocelyne Marsaioli / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Química / Made available in DSpace on 2018-08-25T07:45:46Z (GMT). No. of bitstreams: 1 Martins_LucasGelain_D.pdf: 5948717 bytes, checksum: d64f37183bfefec1cedc88b263d32340 (MD5) Previous issue date: 2014 / Resumo: Nesta tese consiste no estudo de interações supramoleculares utilizando diferentes metodologias de Ressonância Magnética Nuclear de hidrogênio (RMN de 1H), tais como ROESY 1D, RMN-DOSY e RMN-STD. Os sistemas supramoleculares foram abordados em dois casos de estudo diferentes. O Capítulo I tem como objeto de estudo interações do fármaco Dapsona com diferentes carreadores de fármacos (ß-CD, SBE-ß-CD e lipossoma de EPC), com a finalidade de encontrar formulações nas quais a Dapsona seja mais solúvel. Os complexos binários e ternário formados foram determinadas por medidas de difusão molecular. Foram observadas as formações dos complexos Dap/ß-CD, Da-/SBE-ß-CD, Dap/EPC e o ternário Dap/ß-CD/EPC, os quais contribuem para o aumento de solubilidade do fármaco. O objeto de estudo apresentado no Capítulo II é a inibição da enzima acetilcolinesterase por dois alcaloides, a Fisostigmina e a Crinina. Para determinação das constantes de dissociação aparentes foram utilizados os crescimentos iniciais das curvas de saturação obtids por RMN-STD para construção das Isotermas de Langmuir. De acordo com os valores de constantes obtidos foi possível concluir que a AchE tem mais afinidade com a Fisostigmina do que com a Crinina / Abstract: This thesis consists of the supramolecular interactions study applying different Nuclear Magnetic Resonance methodologies (1H NMR) such as 1D ROESY, DOSY-NMR and STD-NMR. The supramolecular systems were addressed in two different case studies. In chapter I Dapsone solubility was the case study. To solve the solubility problem the interactions between Dapsone and various drug carriers (ß-CD , SBE-ß-CD and EPC liposome) were characterized in terms of the binary and ternary complexes structure using NMR method, such as 1D ROESY and STD-NMR and apparent association constants were determined by measuring molecular diffusion using DOSY-NMR. Dap/ß-CD, Dap/SBE-ß-CD, Dap/EPC and Dap/ß-CD/EPC complexes were observed and Dapsone water solubility was increased. The case study in Chapter II is the inhibition of acetylcholinesterase by two alkaloids, Physostigmine and Crinina. The apparent dissociation constants were determined using the initial growth saturation curves obtained by STD-NMRto construct the Langmuir isotherms. The constants showed that the AChE has more affinity for the Physostigmine than Crinine / Doutorado / Quimica Organica / Doutor em Quimica

Acid-sensitive liposome has drawn much interest as drug and gene carriers that release payloads specifically at the low-pH target sites, such as in solid tumors, tissues with inflammation, and ischemia sites. Also, it helps drug/gene to escape endosome trapping and followed lysosome degradation. The goal of this thesis research is to develop novel trans-2-aminocyclohexanols based lipids and their liposome that can be switched by mildly acidic pH. NMR study · show that in certain acidic medium, the amine group on cyclohexane will attract proton and form hydrogen bond with the neighboring -OH. This change will force the bonds switch to from equatorial conformation to axial conformation. This conformational change is transmitted by the structure of the molecular, and induces consequently dramatic conformational change of the two long lipid tails. Fluorescence leakage assay was conducted on liposomes that encapsulated with ANTs/DPX fluorescence dyes. For certain special designed cyclohexane compounds, the pH triggered lipid conformation change will rupture liposome membrane, release the encapsulated content, and thus help them escape lysosome degradation. This would in tum improve the efficiency of liposome drug delivery and gene transfection. Luciferase gene transfection was conducted on B16F10 cultured cells. The lipoplex comprising trans-2-aminocyclohexanollipid 1 significantly enhanced the Luciferase gene expression. The gene transfection efficiency correlated well with the pH-triggered membrane-rupture in the trans-aminocyclohexanol-based lipoplexes.

Thesis (M. Pharm. (Pharmacology)) -- University of Limpopo, 2021 / Introduction: Zebediela Hospital in Limpopo Province is running an outreach programme as part of its chronic care initiative. In the programme, pharmacy personnel visit the feeder clinics attached to the hospital to dispense chronic medicines to patients. This study aimed at evaluating how this pharmacy chronic care outreach programme is performing, by looking at pharmacy personnel, nursing personnel and patients’ perceptions. Method: A cross-sectional descriptive study was conducted at the six feeder clinics attached to Zebediela Hospital in the Lepelle-Nkumpi municipality of the Capricorn district in Limpopo Province using a quantitative research method. This quantitative research was administered in the form of a survey. Questionnaires were used to collect data from patients, nursing personnel and pharmacy personnel. A total of 399 participants (n=399) took part in the study. The participants included 337 patients from six different clinics, 18 pharmacy personnel and 44 nursing personnel. Data was analysed using the SPSS version 25.0. Results: The pharmacy personnel showed that an allocation of more than three personnel per duty roster sufficed. Regarding transport used by pharmacy personnel when embarking on the Pharmacy Chronic Care Outreach Programme, 71.4% of pharmacy personnel indicated that they always used hospital transport in 83.3% of the cases. The study findings showed that, 71% of patients agreed they were satisfied with the pharmacy times for collecting medicines apart from the fact that 65.6% of patients travelled for more than two hours from their respective homes to their nearest clinic. Sixty eight percent of pharmacy personnel perceived the PCCOP model to be reducing patient waiting time at the clinics. Both the patients and nursing personnel were however not satisfied with the pharmacy personnel’s arrival time at the clinic. The other negative aspect reported was the space problem at the clinics where, 77.8% of pharmacy personnel and 54.5% of nursing personnel reported this as not user-friendly. The patients’ satisfaction levels regarding the PCCOP model for “very satisfied” stood at 64.2% and 0.6% for “very dissatisfied”. Both pharmacy and nursing personnel recommended that the PCCOP model be continued with recommendations towards improving human resources and infrastructure. Conclusion: In conclusion, both pharmacy personnel and nursing personnel showed that the outreach programme was a good initiative in the health system and it benefitted patients. However, the concerns mentioned by patients included long waiting times at the clinic and medicine stock outs. As the results show, the pharmacy chronic care outreach programme should be continued, as long as patients’ complaints can be attended to. Key words: Evaluation, Pharmacy Chronic care Outreach Programme, Zebediela

Development of liposome formulation of an amphiphilic anticancer peptide using the ANTS/DPX leakage assay. The effects of lipid composition on the liposomes' resistance to an amphiphilic cyclic peptide c[KS.S.S.KWL W] were studied by the ANTS/DPX leakage assay. One or more unsaturated acyl chains in the phospholipids, small phospholipid headgroup size, the presence of cholesterol, and the presence of PEG-lipid were demonstrated as critical parameters to stabilize the liposome membrane. A liposome formulation of the peptide comprising POPE/POPC/cholesterol/C16 mPEG 2000 ceramide (20.8:31.2:40:8, mol%) was thereby developed with a peptide-encapsulation efficiency of 47.8%. The liposomal cyclic peptide exhibited dose-dependent toxicity to MCF7 human breast cancer cells and stability under incubation. Design, construction and in vitro characterization of a hydrazone-based convertible liposomal system for anticancer drug delivery. A novel PEG-lipid, PEG2ooo-Hz-DHG, with an acid-labile hydrazone linker between the PEG2ooo head group and the lipidic DHG moiety was synthesized. PEG2000-Hz-DHG was relatively stable at normal physiological pH 7.4, but hydrolyzed more quickly at tumor interstitium pH 6.5-7.0 and endosomal/lysosomal pH 5.0. A novel pH-sensitive "Convertible Liposome System" (CLS) was constructed comprising PEG2ooo-Hz-DHG, positively charged lipid DOTAP, and the zwitterionic phospholipid POPC (8:15:77, mol%). CLS converted from neutrally charged "stealth" liposome to positively charged liposome at tumor interstitual pH owing to the hydrolysis ofPEG2ooo-Hz-DHG. The doxorubicin-encapsulated CLS that had been pre-incubated at pH 6.5 for 30 h exhibited more intensive binding and higher toxicity to Bl6-Fl0 murine melanoma and MDA-MB-435S human breast cancer cells than doxorubicin encapsulated in pH-insensitive stealth liposome.

No description available.

This work deals with preparation of microbubble suspension from a mixture of phospholipids, palmitic acid and polyethylene glycol. Properties of prepared systems were studied using bubble tensiometry and dynamic light scattering method and were compared with commercial contrast agent SonoVue®. Suspensions were prepared in various conditions including different atmosphere and increased temperature in some steps of preparation and different solution. Effect of polyethylene glycol addition on surface activity of the system was studied. Surface activity of phospholipids was insignificant. Surface tension decreased with increasing concentration and molecular weight of polyethylene glycol in the system. Effect of different atmosphere and increased temperature showed no substantial trend. It emerged that dynamic light scattering is not suitable for this type of samples because of high polydispersity and phase separation of the system.