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Doctoral Thesis
DOI
10.11606/T.75.2019.tde-14032019-095025
Document
Author
Full name
Beatriz Nogueira Messias de Miranda
E-mail
Institute/School/College
Knowledge Area
Date of Defense
Published
São Carlos, 2018
Supervisor
Committee
Carrilho, Emanuel (President)
Florenzano, Fábio Herbst
Bueno, Cecilia Zorzi
Silva, Caio Marcio Paranhos da
Torre, Lucimara Gaziola de la
Yagui, Carlota de Oliveira Rangel
Title in Portuguese
Mucus-penetrating polymersomes as a potential lung drug delivery system: preparation, in vitro characterization, and biodistribution tests
Keywords in Portuguese
auto-agregação
co-polímeros de bloco
entrega controlada
nanotecnologia
partículas muco penetradoras
vesículas poliméricas
Abstract in Portuguese
O muco protege o corpo humano de partículas externas, mas também representa uma barreira para a entrega de controlada de medicamentos através de nanocarregadores. Para ultrapassar a barreira do muco e impedir mucoadesão, nanopartículas sólidas são normalmente revestidas com polímeros inertes, tais como o polietileno glicol (PEG). No entanto, trata-se de um procedimento relativamente complexa. Nesta tese, estudamos métodos para fabricar nanocarreadores com uma excepcional combinação de propriedades, incluindo uma boa capacidade de mucopenetração e uma grande capacidade de carga. Ao contrário dos métodos convencionais de revestimento, usamos um copolímero dibloco, que consiste em dois blocos hidrofóbicos e hidrofílicos, que se auto-organiza em polimerosomos sob hidratação. Devido à inércia do bloco hidrofílico, estes polimerosomos devem ser, por natureza, muco penetradores. Além disso, sua estrutura oca fornece os polimersomos para serem carregados com carga hidrofílica, enquanto a carga hidrofóbica pode ser transportada através da membrana. Por conta da utilização de um polímero hidrolisável na presença de ácido, ácido poli láctico (PLA) como a espinha dorsal copolímero, demonstramos que estes polimerosomos podem liberar o conteúdo, após aplicação do estímulos externo relacionado ao pH. Os experimentos de rastreamento de partículas demonstraram que os polimersomos se difundem mais rápido do que as partículas não revestidas, em muco de intestino de porco, e testes de biodistribuição apresentaram resultados encorajadores para a entrega localizada de fármacos de maneira mais homogênea, melhorando a biodisponibilidade e efeitos terapeuticos. Mais estudos relacionados ao aumento da eficiência de encapsulação e testes de efetividade in vivo no tratamento de doenças devem ser promovidos. Acreditarmos que combinação das vantagens relacionadas à estrutura vesicular dos polimerossomas, estabilidade, e muco penetração possibilitam o desenvolvimento de uma nova plataforma para a entrega controlada de medicamentos na mucosa.
Title in English
Mucus-penetrating polymersomes as a potential lung drug delivery system: preparation, in vitro characterization, and biodistribution tests
Keywords in English
block copolymers
drug-delivery
mucus-penetrating particles
nanotechnology
polymer vesicles
polymersomes
self-assemble
Abstract in English
Mucus protects the human body by trapping foreign particulates but also poses a barrier for drug delivery by slowing down the mobility of drug carriers. To design mucus penetrating carriers, solid particles are typically coated with inert polymers such as polyethylene glycol (PEG) to prevent mucoadhesion. However, the solid structure of these particles limits their loading capabilities and the process to coat them requires a complex synthesis. In this thesis we studied methods to fabricate nanocarriers with an exceptional combination of properties including a good mucus-penetration capability and loading capacity of hydrophilic and hydrophobic cargos. Unlike conventional coating methods, we use a diblock copolymer, consisting of both hydrophobic and hydrophilic blocks, which self-assembles into polymersomes under hydration. Because of the inertness of the hydrophilic block, these polymersomes should be mucus-penetrating by nature. Moreover, their hollow structure provides the polymersomes to be loaded with hydrophilic cargo, whereas hydrophobic cargo can be carried through the membrane. Importantly, by using a hydrolysable acid-catalyzed polymer (poly lactic acid, PLA) as the copolymer backbone, we demonstrate that these polymersomes can release contents upon application of external pH stimuli. Particle Tracking experiments demonstrated that polymersomes diffuse faster than uncoated particles in porcine intestine mucus, and biodistribution tests displayed encouraging results towards more homogeneous local drug-delivery, helping bioavailability as well as therapeutic efects. More studies related to the increase of encapsulation efficiency, and in vivo disease treatment tests should be promoted. Although we believe that combining the advantages of polymersome carrier, and tunning the membrane composition, this mucus-penetrating carrier we propose may provide as a new platform for mucosal drug delivery.
 
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Publishing Date
2019-03-15
 
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