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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

The effect of particle size and shape on margination and adhesion propensity

Jurney, Patrick Levi 05 October 2011 (has links)
This thesis presents an experimental study of the effect that particle size and shape have on nanoparticle magination and adhesion propensity in micro-capillaries. With the use of half elliptical cross-section microfluidic channels that were fabricated using photolithography as well as wet and dry etching techniques and geometrically mimetic of human microcirculation, particles ranging from 93 to 970 nm were flown and imaged individually adhering to the channel walls. The results show a significant increase in particle adhesion below 200 nm as well as the emergence of a critical particle diameter above which no particle adherence was observed. The volume delivery efficiency was also shown to increase below 200 nm, providing insight for the rational design of nanocarriers for targeted cancer therapeutics. / text
2

PHOTOSWITCHABLE NANOCARRIER WITH REVERSIBLE ENCAPSULATION PROPERTIES

Su, Zhe 03 June 2015 (has links)
No description available.
3

Development of nanocarriers for targeted drug delivery to the placenta

Cureton, Natalie January 2017 (has links)
Pregnancy complications such as fetal growth restriction (FGR) are often attributed to poor uteroplacental blood flow, but the risk of systemic side-effects hinders therapeutic intervention. We have utilised novel placental-specific homing peptides to overcome this and have conjugated these to biocompatible liposomes. Peptide-conjugated liposomes were found to selectively bind to the outer syncytiotrophoblast layer of the human placenta and to the uteroplacental vasculature and labyrinth region of the mouse placenta. The novel vasodilator SE175 was selected as a nitric oxide donor with a favourable stability and release profile, to encapsulate in peptide-conjugated liposomes in an attempt to restore impaired uteroplacental blood flow in a mouse model of FGR, the endothelial nitric oxide synthase knockout mouse. Liposomes containing SE175 or PBS were prepared by lipid film hydration and targeting peptides coupled to the liposomal surface. Vehicle control, free SE175, PBS- or SE175-containing liposomes were intravenously injected on embryonic (E) days 11.5, 13.5, 15.5 and 17.5. Animals were sacrificed at E18.5 and fetal and placental weights recorded. Targeted delivery of SE175 significantly increased fetal weight compared to vehicle control but no other treatment groups, whilst significantly decreasing placental weight, indicating improved placental efficiency. Treatment was well tolerated, having no impact on litter size or resorptions. Targeted delivery of SE175, but no other treatment group, reduced a marker of lipid peroxidation in the placenta, indicating a reduction in oxidative stress. These data suggest that selective delivery of SE175 to the uteroplacental vasculature in peptide decorated liposomes may represent a novel treatment for FGR.
4

MODELAGEM MATEMÁTICA DE PERFIS DE LIBERAÇÃO DE FÁRMACOS A PARTIR DE NANOCARREADORES

Pires, Rafaeli Oleques 29 March 2011 (has links)
Submitted by MARCIA ROVADOSCHI (marciar@unifra.br) on 2018-08-16T12:53:12Z No. of bitstreams: 2 Dissertacao_RafaeliOlequesPires.pdf: 1220663 bytes, checksum: 54cb1e137bd526bbde3fe44c848329e7 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2018-08-16T12:53:12Z (GMT). No. of bitstreams: 2 Dissertacao_RafaeliOlequesPires.pdf: 1220663 bytes, checksum: 54cb1e137bd526bbde3fe44c848329e7 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2011-03-29 / From the 60s, a debate about a new and promising world-wide technologies started, and it was called nanotechnology. Together with the global growth, many fields of research had started to use in their studies, for example, in the pharmaceutical area. Among these innovations, we can include the discovery of new composites, biodegradable products and the development of carries in nanoscale. Among the most used nanocarries there are nanosphere and nanocapsules, showing controlled release compared to conventional drug delivery systems. The release process was studied by some authors that described this process using mathematical equations, one for each use. However, actually, there is no mathematical equation that represents the behavior of the nanocarries, emphasizing the factors relevant at nanoscale. Then, the present study analyzed a specific carrier - nanocapsule - to develop a mathematical equation that represents the behavior of the drug release from polymeric nanocapsules. For the construction of the mathematical model, we used mathematical modeling as methodology. We proved there isn’t change in particle size during the release process, when used poly ( -caprolactone). After that, we noticed that the parameters that interfere in the release process were drug solubility in the oil core of nanocapsule and the encapsulation efficiency. Based in these two parameters, the mathematical model was constructed and then validated, showing to be an good model to describe the drug release profiles from nanocapsules. / A partir da década de 60, iniciou-se o debate sobre uma das mais novas e promissoras tecnologias mundiais, a nanotecnologia. Juntamente com o crescimento mundial, vários campos de pesquisa começaram a utilizá-la em seus estudos, como por exemplo, as inovações na área farmacêutica. Entre estas inovações destacam-se a descoberta de novos compostos, produtos biodegradáveis e o desenvolvimento de carreadores em escala nanométrica: os nanocarreadores. Estes, os mais utilizados são as nanoesferas e nanocápulas, por apresentarem uma liberação sustentada e controlada de fármaco comparada a formulações convencionais. À medida que os anos foram passando, o processo de liberação de fármaco foi sendo explicado e representado por equações matemáticas distintas, cada uma com suas aplicações e peculiaridades. Mas, atualmente, não existe nenhuma equação matemática que represente o comportamento dos nanocarreadores, dando ênfase aos fatores relevantes na nanoescala. Assim, o presente trabalho analisou um carreador específico – nanocápsula – para modelar uma equação matemática que represente o comportamento da liberação de fármacos a partir do mesmo. Para a construção do modelo matemático, foi utilizada a modelagem matemática como metodologia. Foi comprovado que não ocorre modificação no tamanho de partícula durante o processo de liberação, quando utilizado o polímero poli( -caprolactona). Depois disso, percebeu-se que o parâmetro que influencia no processo de liberação é a solubilidade do fármaco no núcleo oleoso da nanocápsula e a taxa de associação às naopartículas. Baseado nestas duas variáveis, foi construído o modelo matemático, que quando validado, mostrou-se ser um excelente modelo para descrever os perfis de liberação de fármacos através das nanocápsulas.
5

Glycated Bovine Serum Albumin for Curcumin Nanoencapsulation: Bio-Nano Interactions

Pfeilsticker Neves, Renata 26 August 2021 (has links)
Glycation of whey proteins results in food-grade composites with modified physicochemical properties. Here, the reaction between glucose and bovine serum albumin (BSA) is promoted under wet-heating conditions. The glycated protein is characterized in depth and compared to the native counterpart and the impact of glycation on properties like net surface charge, particle size and surface hydrophobicity are observed. Conjugation with glucose reduced the surface hydrophobicity of BSA but the interactions between albumin and curcumin became stronger, which contradicts the direct relationship between curcumin binding affinity and protein surface hydrophobicity described in the literature. Nonetheless, curcumin was still capable of quenching the intrinsic fluorescence of the protein after conjugation with glucose and leads to the conclusion that curcumin and BSA interact in a different manner upon glycation. This thesis also depicts mucin as a forthcoming model in the study of nanoparticle interactions with intestinal mucus and glycation posed no effect on such interactions.
6

Desenvolvimento e caracterização de nanopartículas de PLGA funcionalizadas com folato contendo paclitaxel para a otimização da terapia do câncer de ovário / Development and characterization of folate-modified PLGA nanoparticles containing paclitaxel for optimization of ovarian cancer treatment

Luiz, Marcela Tavares 05 April 2018 (has links)
O paclitaxel (PCX) é o fármaco de primeira escolha para o tratamento do câncer de ovário. Contudo, a baixa solubilidade do PCX torna necessária a adição de adjuvantes tóxicos à formulação comercial (Taxol®). Assim, o desenvolvimento de sistemas de liberação nanoestruturados têm sido estudados para promover a redução dos efeitos tóxicos e aumentar a segurança e a eficiência terapêutica do PCX. Uma das estratégias utilizadas para aumentar a seletividade dos nanocarreadores às células tumorais é a funcionalização de suas superfícies com folato, devido a superexpressão dos receptores de folato nas células tumorais. O objetivo do presente trabalho foi desenvolver e caracterizar nanopartículas de PLGA funcionalizadas (NP-PCX-AF) e não funcionalizadas (NP-PCX) para a veiculação do PCX, bem como a avaliação in vitro da eficácia dos sistemas desenvolvidos em linhagens celulares de adenocarcinoma de ovário. Os nanocarreadores foram produzidos pela técnica de nanoprecipitação e avaliados por meio das análises físico-químicas de diâmetro médio de partícula, índice de polidispersão, potencial zeta, eficiência de encapsulação, estabilidade coloidal e espectro de infravermelho. Além disso, foi avaliada a eficácia antitumoral e o uptake dos sistemas desenvolvidos por meio dos ensaios de citotoxicidade celular por resazurina e internalização por microscopia confocal e citometria de fluxo. Os resultados obtidos mostraram que as formulações funcionalizadas e não funcionalizadas apresentaram reduzidos valores de diâmetros médios de partículas (menor que 150 nm) e índices de polidispersão reduzidos (menor que 0,2) com elevada eficiência de encapsulação do PCX, próximo a 100%, o que é adequado para a via de administração endovenosa e promoção do direcionamento ativo e passivo no ambiente tumoral. Os resultados de citotoxicidade celular in vitro em linhagens OVCAR-3 e SKOV-3 demostraram a elevada capacidade das formulações desenvolvidas em liberar o PCX em tempo hábil para ocasionar dano celular. Além disso, a formulação NPPCX- AF apresentou maior capacidade citotóxica que a formulação NP-PCX nas menores concentrações de PCX avaliadas, com redução máxima da viabilidade celular, aproximadamente 22 % para a linhagem celular SKOV-3 e 11% para OVCAR-3, utilizando a concentração de 1000 nM no tempo de 72 horas. Os ensaios de citometria de fluxo e de microscopia confocal mostraram a elevada capacidade de ambos os carreadores serem internalizados através do processo de endocitose, com valores de internalização celular superiores a 80% após 1 hora de tratamento. Estudos in vivo subsequentes serão necessários para confirmar o potencial da formulação NP-PCX-AF no tratamento do câncer de ovário / Paclitaxel (PCX) is a first-line medicinal treatment for ovarian cancer. However, the low PCX water solubility makes necessary the addition of toxic adjuvants to the commercial formulation (Taxol®). Thus, the development of nanostructured delivery systems has been studied to promote a reduction on side effects and an increase on safety and PCX therapeutic efficacy. One of strategies used to increase nanocarriers selectivity to tumor cells is the modification of their surfaces with folate due to folate receptor overexpression on tumor cells membrane. The aim of this work was the development and characterization of folate-modified PLGA nanoparticles (NP-PCXAF) and unmodified nanoparticles (NP-PCX) to PCX delivery, as well as the evaluation of in vitro efficacy of developed systems using human ovarian cancer cell lines. The nanocarriers were produced through nanoprecipitation technique and evaluated through physico-chemical parameters like particle size, polydispersity index, zeta potential, encapsulation efficiency, colloidal stability and infrared spectroscopy. Besides that, antitumoral efficacy and cellular uptake were evaluated using resazurin cytotoxicity assay, confocal microscopy and flow cytometry. The results obtained for folate-modified nanoparticles and unmodified nanoparticles showed low particle size distribution (less than 150 nm) and polydispersity index (less than 0.2) with high PCX encapsulation efficiency (about 100%) which is suitable for intravenous administration and for promoting active and passive targeting to tumor microenvironment. The in vitro cellular cytotoxicity assays of OVCAR-3 and SKOV-3 cell lines demonstrated the high ability of both formulations to release PCX and consequently to cause cellular damage. Furthermore, in lower concentrations NP-PCX-AF formulation showed higher cytotoxicity capacity than NP-PCX with higher cell viability reduction, about 22% for SKOV-3 cell line and 11% for OVCAR-3, using concentration of 1000 nM at 72 hours. Finally, flow cytometry and confocal microscopy assays indicated a high capacity of both nanocarriers to be internalized through endocytosis process. Therefore, subsequent in vivo studies are necessary to confirm the NP-PCX-AF potential for ovarian cancer treatment
7

Utilisation de nanoparticules pour le développement de nouvelles thérapies antituberculeuses / Application of nanoparticles for the development of new antituberculosis therapies

Costa Gouveia, Joana 01 December 2017 (has links)
La tuberculose (TB) est un problème de santé mondiale majeur à l’origine de 10.4 millions de nouveaux cas et 1.8 millions de morts en 2015 selon l’Organisation Mondiale de la Santé (OMS). Cette maladie est causée par la bactérie Mycobacterium tuberculosis (Mtb) qui infecte principalement les poumons et se transmet par l'inhalation d’aérosols contaminés.Le traitement de TB nécessite la prise quotidienne d’antibiotiques pendant 6 mois, dont une mauvaise utilisation peut être à l’origine de l’apparition de souches Mtb multi-résistantes.La nouvelle stratégie de l’OMS, “End TB”, vise à réduire de 90% l’incidence de TB d'ici 2035. Pour y parvenir, il est important de définir de nouvelles approches pour réduire la durée et la toxicité des traitements et améliorer leur efficacité vis-à-vis des bactéries actives et latentes.L’approche abordée lors de ma thèse vise à utiliser des nanoparticules (NP) pour développer de nouvelles thérapies anti-TB. La bibliographie sur le sujet montre que cela pourrait être une stratégie prometteuse. Nous avons par conséquent étudié quatre applications potentielles des NP:1-Vectorisation des médicaments pour les administrer au niveau pulmonaire. L’éthionamide (ETH) est un antibiotique utilisé pour le traitement de TB avec des effets secondaires indésirables. L’ETH est une «pro-drogue» qui nécessite une activation par une monooxygenase bactérienne, dont l’efficacité peut être elle-même augmentée par des molécules chimiques appelées “booster”. Nous avons étudié l’effet de l’ETH et de booster co-encapsulés dans des NP de poly-β-cyclodextrine (pCD) pour le traitement de TB. Nous avons d’abord évalué leur efficacité in vitro sur la croissance extracellulaire et intracellulaire (dans les macrophages) de Mtb grâce à l'utilisation d'un système automatisé de microscopie confocale à haut contenu. Dans les deux essais, nous avons constaté que les médicaments conservaient leur activité après encapsulation et que les NP n'étaient pas cytotoxiques. L’efficacité de ces NP a ensuite été étudiée in vivo chez des souris infectées avec Mtb. La suspension de NP a été délivrée sous forme d’aérosols directement dans les poumons par voie endotrachéale à l’aide d’un Microsprayer Aerosolizer. Une réduction significative de la charge bactérienne dans les poumons de 3 log a été observée après 6 administrations de doses inférieures à celles thérapeutiques.2-Amélioration de la solubilité et biodisponibilité des antibiotiques. La Clofazimine (CLZ) est un antibiotique utilisé dans le traitement de la lèpre et pourrait être, au regard de son efficacité in vitro sur les souches de Mtb multi-résistantes, un candidat potentiel pour celui de TB. La CLZ est extrêmement lipophile, gênant ainsi sa solubilité. Dans notre étude, son encapsulation dans des particules de silice nanoporeuses a stabilisé l'état amorphe de la CLZ et a augmenté radicalement sa solubilité. Après encapsulation ou solubilisation dans le DMSO, la CLZ a d’autre part montré une activité antibactérienne similaire sur Mtb.3-Stabilisation des antibiotiques. La Vancomycine (VAN) est utilisée pour des applications cliniques comme alternative de la pénicilline dans le traitement de Staphylococcus aureus et pourrait être utilisée pour celui de TB. Alors que la VAN présente une faible stabilité dans les milieux biologiques, nous avons montré que l'encapsulation de cet antibiotique à l'intérieur de NP à base de PLGA a amélioré son efficacité tant sur les bactéries Mtb extracellulaires qu’intracellulaires.4-Activité antimycobacterial Intrinsèque de NP. Différentes NP (60 pCD, 1 NanoMOF et 1 NP en argent) ont été évaluées in vitro. Aucune n'a présenté d'activité antituberculeuse intrinsèque prometteuse.En conclusion et au regard des options thérapeutiques limitées pour combattre les souches résistantes et de la rareté de solutions innovantes dans le pipeline de découverte de médicament, ces travaux ont montré que les NP pouvaient constituer une approche anti-TB originale. / Tuberculosis (TB) is a major problem of global health, responsible for 10.4 million new cases and 1.8 million deaths in 2015 according to the World Health Organization (WHO). This disease is caused by inhalation of small aerosol droplets containing Mycobacterium tuberculosis (Mtb), and lungs are usually the major site of infection.TB can usually be treated with a daily six months course of standard, or first-line, anti-TB drugs. If first-line drugs are misused, the onset of multidrug-resistant Mtb can occur.The new WHO global public health strategy “End TB” aims at the reduction of TB incidence 90% by 2035. To reach these ambitious targets, new approaches are urgently needed to get a faster, less harmful and more-efficient treatment for active and latent TB.My thesis focused on the use of nanoparticles (NPs) to develop new anti-TB therapies. Our review of the literature showed that it could be a promising approach. Here, we investigated four potential uses of the NPs.1- Nanocarrier for pulmonary delivery of drugs. Ethionamide (ETH) is a second line antibiotic with high toxicity and several adverse side effects. ETH is a prodrug that requires bioactivation by a bacterial monooxygenase, which can be enhanced by chemical molecules named “boosters”. We investigated the simultaneous delivery of ETH and boosters coencapsulated in biodegradable poly-β-cyclodextrin (pCD) based NPs by the pulmonary route for the treatment of TB. First, we evaluated the in vitro efficacy of the designed formulations on Mtb extracellular growth and intracellular growth inside macrophages using an automated confocal high-content microscopy system. And we found for both assays that the drugs maintained their activity after encapsulation and the pCD were not cytotoxic. Given these promising results, their efficacy was then tested in vivo. The NPs suspension, administered directly into mouse lungs by endotracheal way using a Microsprayer® aerosolizer, was proved to be well-tolerated and led to a 3-log decrease of the pulmonary mycobacterial load after 6 administrations and using lower doses than the therapeutic ones.2- Enhancement of the solubility and the bioavailability of antibiotics. Clofazimine (CLZ) is an antibiotic usually used in a combination therapy for the treatment of leprosy and could be a potential candidate for the treatment of TB because of its in vitro efficacy on resistant Mtb strains. CLZ is extremely lipophilic and has important solubility problem. In our study, its encapsulation in nanoporous silica particles stabilized the amorphous state of CLZ and dramatically increased the drug solubility. On the other hand, CLZ encapsulated in nanoporous silica particles or efficiently dissolved in DMSO showed a similar antibacterial activity on Mtb, validating the assessment of solubility of CLZ by encapsulation.3- Improvement of the antibiotic stabilization. Vancomycin (VAN) is used for clinical applications for nearly 50 years as a penicillin alternative to treat penicillinase-producing strains of Staphylococcus aureus. VAN can be used for TB treatment as a repurpose. While VAN presented low stability in biological media at 37°C, we showed that the encapsulation of this antibiotic inside PLGA-based NPs enhanced its efficacy both on extracellular and intracellular bacteria.4- Intrinsic antimycobacterial activity of NPs. Different NPs (60 pCD, 1 NanoMOF, and 1 silver NP) were tested in vitro but none presented promising intrinsic antitubercular activity. However some pCD were slightly active in vitro on extracellular Mtb but cytotoxic.In conclusion, these works demonstrated that nanoparticles can provide a novel anti-TB approach regarding the limited therapeutic options to fight drug-resistant Mtb and the scarcity of novel antituberculosis drugs in the drug discovery pipeline.
8

EFEITO DAS β-CICLODEXTRINAS SOBRE PARÂMETROS BIOQUÍMICOS, DO METABOLISMO ENERGÉTICO E DO ESTRESSE OXIDATIVO EM RATOS WISTAR

Oliveira, Amanda Lima de 30 November 2012 (has links)
Made available in DSpace on 2018-06-27T18:56:01Z (GMT). No. of bitstreams: 2 Amanda Lima de Oliveira.pdf: 513074 bytes, checksum: 393de3a3c8893cb2dad143281cc76ca4 (MD5) Amanda Lima de Oliveira.pdf.jpg: 3435 bytes, checksum: d98e4a9d95435991a70b3e949f124696 (MD5) Previous issue date: 2012-11-30 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Cyclodextrins (CDs) are cyclic oligosaccharides formed by 6 (αCD), 7 (bCD) or 8 (γCD) glucose units with an internal hydrophobic cavity and outside surface hydrophilic. These three derivatives, the b-cyclodextrin (bCD) seems to be the most advantageous for pharmaceutical use for their availability, cavity size and low cost. The CDs have a future quite promising for their properties as greater absorption of drugs through the biological barriers and time of release, however, some types may not be considered non-toxic. The objective of this study was to investigate the intraperitoneal administration of βCD, M-β-CD and HP-ß-CD for 8 weeks with administered dose of 65.65 mg of CDs/kg rats/day, on parameters of biochemical analyzes, enzymes of energy metabolism, enzymes tiolicas sensitive to increase reactive oxygen species and to make this relationship, also evaluate parameters of oxidative stress in cerebral cortex, liver, kidneys and heart of wistar rats. The results showed that for the group treated with βCD there has been a significant increase in serum urea and creatinine levels, indicating nephrotoxicity, however not related to the other parameters. There was also a great reduction in serum levels of iron for the 3 CDs. The heart showed a reduction in the activity of CKmitocondrial and increase for AK by M-β-CD and reduction of CKmit by HP-ß-CD, but showed a reduction in the levels of diclorofluorceina (DCF) to the 3 CDs and protein carbonyl) by βCD. For the rim there was no significant change in comreducao activity of CKmit by HP-β-CD. In liver tissue, the βCD and M-β-CD reduced the activity of PK, but this is not reflected in blood glucose levels. In the cerebral cortex, the βCD reduced the activity of enzymes CK mitochondrial and PK, also reduced TBARS, but increased carbonyl protein. The indices lipidemic reduced reported by other researchers was not observed in this work, because the group of M-β- CD has a significant increase in serum levels of LDL cholesterol, in addition to aspartate aminostransferase AST, albumin, total protein, alkaline phosphatase, sodium, calcium, magnesium and phosphate. Our results indicate that some CDs alter enzymes crucial for energy metabolism, mainly of brain tissue with a reduction in activity and the PK by βCD. If changes in the activity of these enzymes occur in people who use drugs by intraperitoneal route, it is possible that the energy metabolism and brain functioning may be affected causing damage to the tissue. However more studies are needed to elucidate how there was a reduction of serum iron and as the cyclodextrins affect a structure so well protected by blood-brain barrier as the brain. / As ciclodextrinas (CDs) são oligossacarídeos cíclicos formados por 6 (αCD), 7 (bCD) ou 8 (γCD) unidades de glicose com uma cavidade interna hidrofóbica e superfície externa hidrofílica. Destes três derivados, a b-ciclodextrina (bCD) parece ser a mais vantajosa para utilização farmacêutica pela sua disponibilidade, tamanho da cavidade e baixo custo. O interesse pelas CDs se dá pelas suas propriedades como maior absorção dos fármacos através das barreiras biológicas e tempo de liberação, entretanto, alguns tipos não podem ser considerados atóxicas. O objetivo deste estudo foi investigar a administração intraperitoneal de βCD (Beta Ciclodextrina), M-β-CD (Metil Beta Ciclodextrina) e HP-β-CD (Hidroxypropil Beta Ciclodextrina) durante 8 semanas com dose administrada de 65,65 mg das CDs/kg rato/dia, sobre parâmetros de análises bioquímicas, de enzimas do metabolismo energético, enzimas tiólicas sensíveis ao aumento de espécies reativas e para fazer a relação, também avaliar parâmetros de estresse oxidativo em córtex cerebral, fígado, rins e coração de ratos wistar. Os resultados mostraram que para o grupo tratado com βCD houve um aumento significativo nos níveis séricos de uréia e creatinina, indicando nefrotoxidade, porém não relacionada com os demais parâmetros. Também houve uma grande redução nos níveis séricos de ferro para as 3 CDs. O coração apresentou redução na atividade da Creatinaquinase mitocondrial (CKmit) e aumento para Adenilatoquinase (AK) pela M- β-CD e redução da CKmit pela HP-β-CD, porém apresentou uma redução nos níveis de diclorofluoresceína (DCF) para as 3 CDs e carbonilas proteicas pela βCD. Para o rim houve alteração significativa com redução na atividade da CKmit pela HP-β-CD. No tecido hepático, a βCD e M-β-CD reduziram a atividade da Piruvatoquinase (PK), porém isto não refletiu nos níveis glicêmicos. No córtex cerebral, a βCD reduziu a atividade das enzimas CK mitocondrial e PK, também reduziu TBARS (Espécies reativas ao ácido tiobarbitúrico), mas aumentou carbonilas proteicas. Os índices lipidêmicos reduzidos relatados por outros pesquisadores não foi observado neste trabalho, pois o grupo da M-β-CD apresentou um aumento significativo nos níveis séricos de LDL (lipoproteína de baixa densidade), além de AST (aspartato aminostransferase), albumina, proteínas totais, fosfatase alcalina, sódio, cálcio, magnésio e fosfato. Os resultados indicam que algumas CDs alteram enzimas cruciais do metabolismo energético, principalmente do tecido cerebral com redução na atividade da PK pela βCD. Possíveis alterações na atividade destas enzimas podem afetar o metabolismo energético e o funcionamento cerebral causando dano ao tecido. Entretanto mais estudos são necessários para elucidar de que forma ocorreu a redução sérica de ferro e como as ciclodextrinas afetaram uma estrutura tão bem protegida pela barreira hemato-encefálica como a cerebral.
9

CARACTERIZAÇÃO DO RESVERATROL COMPLEXADO À HP-β-CD E O EFEITO DESTE COMPLEXO SOBRE PARÂMETROS DO METABOLISMO ENERGÉTICO EM RATOS HIPERGLICÊMICOS

Nishihira, Vivian Shinobu Kishimoto 27 August 2013 (has links)
Made available in DSpace on 2018-06-27T18:56:09Z (GMT). No. of bitstreams: 2 Viviam Shinobu Kishimoto Nishihira.pdf: 1449623 bytes, checksum: 695b00eba00a141bcd8f0d653cbcb917 (MD5) Viviam Shinobu Kishimoto Nishihira.pdf.jpg: 3806 bytes, checksum: 4f2ac7a7687ef7a61a7e4f8e64b1c9ef (MD5) Previous issue date: 2013-08-27 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The use of nanoparticles (NPs) as drugs carriers has been widely studied, among these NPs are highlighted the cyclodextrins (CDs), they are cyclic oligosaccharides composed of glucose residues with hydrophobic cavity and a hydrophilic external surface, which enables the formation inclusion complexes with lipophilic substances such as resveratrol (RSV) thereby increasing their solubility in water. RSV is a polyphenol founded in products derived from plants, for example, in the grape skins has been extensively studied for its antioxidant properties, anti-inflammatory, as well as their estrogenic effects in the prevention and treatment of various metabolic disorders, including, Diabetes. The aims of this study were to characterize the complex of RSV in HP-β-CD, validate the method on UV/vis spectrophotometer and after the in vitro treatment, comparing the effect of oral administration of free RSV and complexed with HP-β-CD (Hidroxypropil-Beta-Cyclodextrin) for two months, dose giving of 1 mg RSV / kg rat / day, on the enzyme activity of energy metabolism, pyruvate kinase (PK), creatine kinase (CK), adenylate kinase (AK), in tissue such as kidney, liver, heart, cerebral cortex and hippocampus and lactate dehydrogenase (LDH) in cerebral cortex and hippocampus, some of these compromised in diabetes. And also examine the toxicity and hypoglycemic effect of the complex through biochemical serum parameters. With the characterization been demonstrated that complexation was successfully. On the other hand, with to validate method, the analytical parameters studied indicate a simple, fast and precise, accurate and can be applied safely and reliably to determine the level of RSV incorporated into the inclusion complex. The hypoglycemic effect of RSV glycemic was not observed in our study when treated with both free RSV and complexed RSV. All diabetic groups showed elevated levels of urea, which may have derived from protein catabolism of DM1, however, no increase in the levels of creatinine, a marker of renal injury. Moreover, almost all results of the activities PK, AK, and CKmit CKcit showed no significant difference, indicating again that the kidney tissue is not compromised. Lipidemics levels are associated with vascular injury in DM1. High concentrations of triacylglycerol (TG) and very low density lipoprotein (VLDL) for diabetic groups were reversed by the complex and did not occur with free RSV. This lipid imbalance seems to be due to liver dysfunction, because the levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST) and albumin are not altered in diabetic control. All diabetic groups showed significant increases in the activity of alkaline phosphatase (ALP). Several parameters were not affected after two months of treatment as albumin, high-density lipoprotein (HDL), uric acid, direct bilirubin (DB), total bilirubin (TB), total protein (TP), calcium (Ca), iron (Fe) and phosphate. Insulin stimulates the functioning of the liver PK in the absence of this hormone, a feature in DM1, the liver PK activity is reduced in all diabetic groups characteristic inhibition by insulin deficiency, both free RSV and the complex did not revert this situation, which can be proven by hyperglycemia and elevated serum concentration of fructosamine. In the heart, the administration of the complex reduced the activity of PK in diabetic rats and CKcit, but increased the activity of CKmit. The complex also reduced the activity of PK and CKcit in the cerebral cortex of normoglycemic animals. In the hippocampus, the activity of PK is high for all hyperglycemic animals in all diabetic groups and these complexes reinforce this elevation. For the diabetic groups in this tissue, the free RSV strongly reduced activity in both fractions of CK complex and reduces the activity of CKcit. For the diabetic group, RSV also inhibits CKmit complex and inhibits the activity of CKcit though both reductions appear to be offset by an increase in the activity of PK. Catches the attention that HP-β-CD significantly reduces the activity of AK compared to the two controls: diabetic and non diabetic.It is concluded that despite the complex does not affect biochemical markers of toxicity such as creatinine, urea, AST and ALT, it reduces the activity of key enzymes of energy metabolism in various organs, wich can alter cellular energy homeostasis. These findings reinfore the need to evaluate the mechanisms of action of nanoparticles. / A utilização de nanopartículas (NPs) como carreadores de fármacos tem sido amplamente estudada, dentre essas NPs se destacam as ciclodextrinas (CDs), que são oligossacarídeos cíclicos compostos por resíduos de glicose com uma cavidade hidrofóbica e superfície externa hidrofílica. O que permite a formação de complexos de inclusão com substâncias lipofílicas como o resveratrol (RSV) aumentando assim sua solubilidade em água. O RSV é um polifenol encontrado em produtos derivados de plantas como, por exemplo, na casca da uva, o qual tem sido extensivamente estudado pelas suas propriedades antioxidantes, anti-inflamatórias, seus efeitos estrogênicos bem como na prevenção e tratamento de algumas doenças metabólicas, entre elas, o diabetes. Os objetivos deste estudo foram caracterizar o complexo do RSV com a hidroxipropil-beta-ciclodextrina (HP-β-CD), validar o método através do espectrofotômetro no UV/vis e avaliar o efeito da administração por via oral de 1 mg de RSV livre e complexado/kg rato/dia, durante dois meses, em ratos normo- e hiperglicêmicos, sobre as atividades de enzimas chaves do metabolismo energético, piruvatocinase (PK), creatinacinase (CK), adenilatocinase (AK), de tecidos como rim, fígado, coração, córtex cerebral e hipocampo, e lactato desidrogenase (LDH) no córtex cerebral e hipocampo, alguns destes comprometidos no diabetes. E, também analisar a toxicidade e efeito hipoglicemiante do complexo, através de parâmetros séricos bioquímicos. As caracterizações na espectroscopia do infravermelho (IV) e de ressonância magnética nuclear de hidrogênio (RMN 1H) comprovaram que a complexação foi realizada com sucesso. Por outro lado, foi realizada a validação do método, os parâmetros analíticos estudados indicam um método simples, rápido, preciso e exato que pode ser aplicado com segurança e confiabilidade na determinação do teor de RSV incorporado no complexo de inclusão. O efeito hipoglicemiante do RSV, não foi observado neste trabalho tanto para o grupo diabético tratado com o RSV livre quanto aquele tratado com o complexo. Todos os grupos diabéticos apresentaram níveis elevados de ureia, porém, não houve elevação nos níveis de creatinina, um marcador de lesão renal. Da mesma forma, as atividades da PK, AK, CKmit e CKcit deste tecido praticamente não apresentaram alterações entre os grupos. As concentrações elevadas de triacilglicerol (TAG) e lipoproteína de muito baixa densidade (VLDL) para os grupos diabéticos foram revertidas pelo complexo, mas não pelo RSV livre. Este desequilíbrio lipídico parece não ser decorrente de disfunção hepática, pois os níveis das transaminases ALT, AST e albumina não estão alterados no controle diabético. Todos os grupos diabéticos apresentaram aumentos expressivos na atividade da fosfatase alcalina (FAL). Vários parâmetros não foram afetados após os dois meses de tratamento como albumina, lipoproteína de alta densidade (HDL), bilirrubina direta (BD), bilirrubina total (BT), proteína total (PT), colesterol total (CT), cálcio (Ca), ferro (Fe) e fosfato. A atividade da PK hepática encontra-se reduzida em todos os grupos diabéticos, inibição característica pela deficiência de insulina, e tanto RSV quanto o complexo não reverteram este quadro, o que pode ser comprovado pela hiperglicemia e concentração elevada de frutosamina sérica. No coração, o complexo reduziu a atividade da PK de ratos diabéticos e da CKcit, porém elevou a atividade da CKmit. O complexo também reduziu a atividade da CKcit no córtex cerebral dos animais normoglicêmicos, mas elevou a atividade da fração mitocondrial. Já no hipocampo, a atividade da PK encontra-se elevada para todos os grupos hiperglicêmicos e o complexo reforça este aumento. Nos animais normoglicêmicos, o complexo inibiu a atividade das duas frações da CK e também da fração mitocondrial dos diabéticos. Conclui-se que apesar do complexo não afetar marcadores de toxicidade como creatinina, ureia, AST e ALT, ele altera a atividade de importantes enzimas do metabolismo energético em vários órgãos, o que pode alterar a homeostasia energética celular. Estes achados reforçam a necessidade de avaliar mecanismos de ação de nanopartículas.
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DESENVOLVIMENTO E CARACTERIZAÇÃO DE UMA NOVA BLENDA POLIMÉRICA DE POLI(METIL METACRILATO)-POLI(ETILENOGLICOL) PARA PRODUÇÃO DE NANOCÁPSULAS E APLICAÇÃO EM DRUG DELIVERY

Santos, Cayane Genro 20 March 2017 (has links)
Submitted by MARCIA ROVADOSCHI (marciar@unifra.br) on 2018-08-20T12:23:08Z No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Tese_CayaneGenroSantos.pdf: 3426105 bytes, checksum: 7a9b15fe21608009c9d6ca592e708bf4 (MD5) / Made available in DSpace on 2018-08-20T12:23:08Z (GMT). No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Tese_CayaneGenroSantos.pdf: 3426105 bytes, checksum: 7a9b15fe21608009c9d6ca592e708bf4 (MD5) Previous issue date: 2017-03-20 / Polymers are part of our life and have many applications in different branches of industry. In pharmaceutics they are widely used in systems for the modified release of drugs. Polymer blends appear as an alternative to the use of individual polymers and have been utilized to produce nanocarriers. In the present study a polymeric material was developed to respond to a specific aim of the pharmaceutical industry, which is the sustained release of drugs. For this purpose, for the first time, a polymeric blend of poly(methyl methacrylate) - polyl(ethylenoglycol) (PMMA-PEG) was developed for the production of nanocapsules and the appication for the sustained delivery of a model-pharmaceutical, in this case, simvastatin. Tests were also performed for the characterization and stability of this nanostructure. Further, the cyto and genotoxicity of the nanocapsules in mononuclear cells of peripheral blood was evaluated, and an intermediate product was developed (nanocapsules of powdered simvastatin) to be used later by the pharmaceutical industry. The polymer blend of PMM-PEG was obtained with a high yield, 94 ± 3.7%. The infrared spectrum shows the typical bands at 3349 cm-1 and 2922 cm-1 corresponding to the vibration of the lengthening of -O-H and -C-H bonds. Characteristic bands at 1731 and 1102 cm-1 were attributed to -C=O and -C-O-C lengthening. In the 1H-RMN spectrum the sign of methylenic protons was observed at 3.68 ppm (-CH2OCH2-) of PEG and the peak at 3.61 ppm of the protons of cluster -OCH3 of PMMA. The molecular weight determined by GPC was 101.581 Da and the polydispersion index was 5.342. Analyses of DSC suggested that the mixture is a molecularly well dispersed system, and the curves of TGA indicated two weight losses in relation to both polymers. The nanocapsules produced by the polymeric blend presented a particle size and polydispersion index of 198.2 ± 1.4 nm and 0.08 ± 0.01 for the white nanocapsules and 194.4 ± 1.7 nm and 0.07 ± 0.00 for the nanocapsules with simvastatin. The zeta potential value was -11.22 ± 3,01 mV for the nanocapsule with simvastatin and -9.19 ± 0.26 mV for the white nanocapsules, and efficiency of simvastatin encapsulation was high, 98.64 ± 0.00%. The condition of refrigerated storage (± 4 ºC) was what best ensured the preservation of the physicochemical characteristics of the suspensions over 90 days. The cyto and genotoxicity tests indicated that the samples tested were not toxic and, therefore, are safe for biomedical application. The release of the drug from the nanocapsules was more sustained than its free form and the presence of PEG in the polymer blend of PMMA-PEG modified the release mechanism and increased the quantity of simvastatin released compared to the nanocapsules produced only with PMMA. Forty-five per cent release of simvastatin was observed in 24 hours, from the nanocapsules produced by the PMMA-PEG blend, and 34% from the capsules produced only with PMMA., while the non-encapsulated simvastatin was fully released in 17 hours. Finally, the suspensoins were efficiently dried by spray-drying, and resulted in an intermediate product with a yield of 66.83% and presented adequate physicochemical characteristics. Thus, we can conclude that the polymer blend was obtained successfully through a simple, efficient process, and served to develop a nanocarrier of drug.s The nanocapsules produced by the polymer blend promoted a sustained release of the drug, indicating that these nanocapsules are good candidates for use as drug carriers. / Os polímeros fazem parte da nossa vida e têm inúmeras aplicações em diversos setores industriais. Na área farmacêutica, são amplamente empregados em sistemas de liberação modificada de fármacos. As blendas poliméricas surgem como uma alternativa ao uso de polímeros individuais e têm sido utilizadas para produção de nanocarreadores. Neste trabalho, desenvolveu-se um material polimérico para atender a um fim específico da indústria farmacêutica, que é a liberação sustentada de fármacos. Para isso, produziu-se pela primeira vez, uma blenda polimérica de poli(metil metacrilato) (PMMA)-poli(etilenoglicol) (PEG) para a produção de nanocápsulas e aplicação na entrega sustentada de um fármaco-modelo, nesse caso, a sinvastatina. Realizaram-se testes de caracterização e estabilidade dessa nanoestrutura. Avaliou-se a cito e genotoxicidade das nanocápsulas em células mononucleares de sangue periférico e desenvolveu-se um produto intermediário (nanocápsulas de sinvastatina em pó) para ser usado posteriormente pela indústria farmacêutica. A blenda polimérica de PMMA-PEG foi obtida com alto rendimento, 94 ± 3,7%. O espectro de infra-vermelho mostra as bandas típicas em 3349 cm-1 e 2922 cm-1 correspondente à vibração de alongamento das ligações -O-H e -C-H. Bandas características em 1731 e 1102 cm-1 foram atribuídas ao alongamento -C=O e -C-O-C-. No espectro de 1H-RMN foi observado o sinal de prótons metilênicos em 3,68 ppm (-CH2OCH2-) do PEG e o pico em 3,61 ppm dos prótons do grupamento -OCH3 do PMMA. O peso molecular determinado por GPC foi 101.581 Da e índice de polidispersão foi 5,342. Análises de DSC sugeriram que a mistura é um sistema molecularmente bem disperso e as curvas de TGA indicaram duas perdas de peso em relação a ambos os polímeros. As nanocápsulas produzidas pela blenda polimérica apresentaram tamanho de partícula e índice de polidispersão de 198,2 ± 1,4 nm e 0,08 ± 0,01 para as nanocápsulas brancas e de 194,4 ± 1,7 nm e 0,07 ± 0,00 para as nanocápsulas com sinvastatina. O valor de potencial zeta foi -11,22 ± 3,01 mV para as nanocápsulas com sinvastatina e de -9,19 ± 0,26 mV para as nanocápsulas brancas e a eficiência de encapsulação da sinvastatina foi elevada, 98,64 ± 0,00%. A condição de armazenamento sob refrigeração (± 4 ºC) foi a que melhor garantiu a preservação das características físico-químicas das suspensões ao longo de 90 dias. Os ensaios de cito e genotoxicidade indicaram que as amostras testadas não foram tóxicas e, portanto, são seguras para aplicação biomédica. A liberação do fármaco das nanocápsulas foi mais sustentada do que a sua forma livre e a presença do PEG na blenda polimérica de PMMA-PEG modificou o mecanismo de liberação e aumentou a quantidade de sinvastatina liberada quando comparada com nanocápsulas produzidas apenas com o PMMA. Observou-se 45% de liberação, em 24 horas, da sinvastatina das nanocápsulas produzidas pela blenda de PMMA-PEG e 34% das nanocápsulas produzidas apenas com PMMA, enquanto a sinvastatina não encapsulada foi liberada totalmente em 17 horas. Por fim, a secagem das suspensões por spray-drying foi eficiente e resultou em um produto intermediário cujo rendimento foi de 66,83% e apresentou características físico-químicas adequadas. Assim, podemos concluir que a blenda polimérica foi obtida com sucesso através de um processo simples e eficiente e serviu para o desenvolvimento de um nanocarreador de fármacos. As nanocápsulas produzidas pela blenda polimérica promoveram uma liberação sustentada do fármaco indicando que estas nanocápsulas são bons candidatos para uso como transportadores de fármacos.

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