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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

Microesferas de PCL como sistema de libera??o controlada de herbicida glifosato / PCL Microspheres as Controlled Release System of Glyphosate Herbicide

Holz, Juliana Pelisoli 30 October 2017 (has links)
Submitted by PPG Engenharia e Tecnologia de Materiais (engenharia.pg.materiais@pucrs.br) on 2018-10-18T18:56:51Z No. of bitstreams: 1 TESE_JULIANA_PELISOLI_HOLZ_HOMOLOGA??O.pdf: 1545312 bytes, checksum: f915686f1b1663c40d8c1dba1f335b6d (MD5) / Rejected by Sheila Dias (sheila.dias@pucrs.br), reason: Devolvido devido ? falta da capa institucional no arquivo PDF. on 2018-10-19T12:03:09Z (GMT) / Submitted by PPG Engenharia e Tecnologia de Materiais (engenharia.pg.materiais@pucrs.br) on 2018-10-19T20:35:58Z No. of bitstreams: 1 TESE_JULIANA_PELISOLI_HOLZ_HOMOLOGA??O_PUCRS.pdf: 1572906 bytes, checksum: 81eb2ad136f458f673745debe4a6fa13 (MD5) / Approved for entry into archive by Sheila Dias (sheila.dias@pucrs.br) on 2018-10-22T11:20:21Z (GMT) No. of bitstreams: 1 TESE_JULIANA_PELISOLI_HOLZ_HOMOLOGA??O_PUCRS.pdf: 1572906 bytes, checksum: 81eb2ad136f458f673745debe4a6fa13 (MD5) / Made available in DSpace on 2018-10-22T11:30:50Z (GMT). No. of bitstreams: 1 TESE_JULIANA_PELISOLI_HOLZ_HOMOLOGA??O_PUCRS.pdf: 1572906 bytes, checksum: 81eb2ad136f458f673745debe4a6fa13 (MD5) Previous issue date: 2017-10-30 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES / Glyphosate is the most widely used herbicide in the world, due to its broad spectrum of action. But there is a need for reduction measures in its application, due to the risks associated with contamination of water and the environment. The development of controlled release systems appears as an alternative to minimize the application of this herbicide. This work aimed at the preparation of glyphosate-containing Poly (?-caprolactone) (PCL) microspheres. These were characterized as to their morphology, structure, physicochemical properties, and a bioassay was carried out to evaluate their use in rice cultivation, in order to create a possible alternative for the use of these herbicides in plantations. The PCL / glyphosate microspheres produced by the multiple emulsion technique and solvent evaporation were in the form of solid beads with mean sizes of 3 ?m ? 0.6 ?m. It was possible to incorporate 9.3% glyphosate in relation to the polymer mass in the formed particles, revealing an efficiency of incorporation IE of 30.9%. From the techniques used to quantify the incorporated glyphosate (UVvis, TGA and CHN), it can be stated that with the increase of glyphosate concentration in the formulation there is an increase in its IE. On the other hand, this increase leads to a decrease in the average size of the microspheres. The release of the herbicide from the microspheres was evidenced by bioassays, and in the assessment of the glyphosate release profile of the microspheres, it can be seen that approximately 17% of the herbicide was released into the medium, 0.01 M CaCl2 solution at room temperature, after 360 minutes of testing. This study allowed to affirm that the theoretical model described by Korsmeyer-Peppas is adequate to characterize the phenomenon of transport of glyphosate release from the microspheres, revealing an anomalous transport not governed by Fick diffusion. / O glifosato ? o herbicida mais utilizado no mundo, devido ao seu amplo espectro de a??o. Por?m existe a necessidade de medidas de redu??o na sua aplica??o, devido aos riscos associados ? contamina??o da ?gua e do meio ambiente. O desenvolvimento de sistemas de libera??o controlada surge como uma alternativa para minimizar a aplica??o deste herbicida. Este trabalho teve como objetivo a prepara??o de microesferas de Poli (?-caprolactona) (PCL) contendo glifosato. Estas foram caracterizadas quanto a sua morfologia, estrutura, propriedades f?sicoqu?micas, e ainda, realizou-se um bioensaio para a avalia??o do seu uso na cultura do arroz, a fim de criar uma poss?vel alternativa para o uso destes herbicidas em planta??es. As microesferas de PCL/glifosato produzidas atrav?s da t?cnica de emuls?o m?ltipla e evapora??o do solvente apresentaram a forma de esferas s?lidas com tamanhos m?dios de 3 ?m ? 0,6 ?m. Foi poss?vel incorporar 9,3% de glifosato em rela??o ? massa de pol?mero nas part?culas formadas, revelando uma efici?ncia de incorpora??o (EI) de 30,9%. A partir das t?cnicas utilizadas para quantifica??o do glifosato incorporado (UVvis, TGA e CHN), pode-se afirmar que com o aumento da concentra??o de glifosato na formula??o existe um aumento de sua EI. Por outro lado este aumento acarreta na diminui??o no tamanho m?dio das microesferas. A libera??o do herbicida das microesferas foi evidenciada atrav?s de bioensaios, e na avalia??o do perfil de libera??o do glifosato das microesferas, pode-se constatar que aproximadamente 17% do herbicida foi liberado para o meio, solu??o de CaCl2 0,01 M em temperatura ambiente, ap?s transcorridos 360 minutos de ensaio. Este estudo permitiu afirmar que o modelo te?rico descrito por Korsmeyer-Peppas ? adequado para caracterizar o fen?meno de transporte de libera??o do glifosato das microesferas, revelando um transporte an?malo n?o governado pela difus?o de Fick.
2

Microemuls?o contendo Crisina com potencial a??o antinociceptiva

Ramalho, ?zola Morais de Medeiros 22 February 2018 (has links)
Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2018-04-02T13:58:33Z No. of bitstreams: 1 IzolaMoraisDeMedeirosRamalho_DISSERT.pdf: 4457596 bytes, checksum: 5f1145abd03b8d8ff0715911db87789b (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2018-04-05T11:02:28Z (GMT) No. of bitstreams: 1 IzolaMoraisDeMedeirosRamalho_DISSERT.pdf: 4457596 bytes, checksum: 5f1145abd03b8d8ff0715911db87789b (MD5) / Made available in DSpace on 2018-04-05T11:02:29Z (GMT). No. of bitstreams: 1 IzolaMoraisDeMedeirosRamalho_DISSERT.pdf: 4457596 bytes, checksum: 5f1145abd03b8d8ff0715911db87789b (MD5) Previous issue date: 2018-02-22 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / A Crisina (5,7-Dihidroxiflavona) pertence ? classe flavona de flavonoides. ? encontrada naturalmente em mel, pr?polis, e v?rias esp?cies de plantas, incluindo esp?cies do g?nero Pelargonium, Passiflora e da fam?lia Pinaceae. A Crisina (CS) ? atualmente comercializada como suplemento diet?tico e, como outros flavonoides, tamb?m exibe diversos efeitos farmacol?gicos, dentre os quais est?o a atividade antinociceptiva e anti-inflamat?ria. Entretanto, sua efic?cia tem sido limitada devido ? sua baixa biodisponibilidade oral. As microemuls?es (ME) s?o sistemas de libera??o modificada definidos como sistemas termodinamicamente est?veis e isotropicamente transl?cidos de dois l?quidos imisc?veis, usualmente ?gua e ?leo, estabilizados por um filme interfacial de tensoativo, e quando necess?rio um cotensoativo. Estes sistemas possuem a capacidade de solubilizar compostos hidrof?bicos, melhorar absor??o, biodisponibilidade e estabilidade, incrementar a efic?cia e reduzir a toxicidade de f?rmacos incorporados. O objetivo deste trabalho foi a obten??o, caracteriza??o de um sistema microemulsionado para incorpora??o da CS e avalia??o da atividade antinociceptiva desse. A formula??o obtida atrav?s de um diagrama de fase tern?rio foi caracterizada f?sico-quimicamente quanto ao pH, condutividade e ?ndice de refra??o. Suas caracter?sticas estruturais e morfol?gicas foram analisadas atrav?s de espalhamento de luz din?mica (DLS) e microscopia de luz polarizada (MLP). Enquanto, a estabilidade da formula??o foi avaliada atrav?s dos estudos de estresse por centrifuga??o, aquecimento-resfriamento e congelamento-descongelamento. O perfil de libera??o in vitro foi determinado utilizando o modelo de c?lulas de Franz. A avalia??o analg?sica foi realizada atrav?s de um teste comportamental que avalia o aumento do limiar de for?a sobre a pata dos camundongos para analisar o reflexo de retirada atrav?s de um analges?metro. Al?m da determina??o da capacidade de preven??o da forma??o de citocinas inflamat?rias avaliadas atrav?s de ELISA imunoensaio. Para isso foi administrada 30 minutos ap?s a indu??o por carragenina a dose de 25mg/kg de CS e MECS. A ME desenvolvida ? constitu?da por 5 % de miristato de isopropila, 55 % de ?gua e 40 % de LAS?, e apresentou pH compat?vel com a administra??o via oral, condutividade condizente com sistemas ?leo em ?gua, al?m de comportamento isotr?pico. A distribui??o de tamanho de got?culas foi do tipo monomodal e homog?neo, com tamanhos m?dios de got?culas de 170,7 ? 5,3 e 158,9 ? 26,7 nm, e potencial zeta negativo de -16,1 ? 1,9 e -10 ? 2,1, para formula??es com e sem CS, respectivamente. A ME mostrou-se est?vel frente aos estresses t?rmicos e por centrifuga??o. A libera??o in vitro da MECS obedeceu ao modelo cin?tico de ordem zero e preveniu a forma??o de citocinas inflamat?rias (redu??o de TNF ? e aumento de IL-10, p<0,01), al?m de apresentar atividade antinociceptiva no modelo de hiperalgesia induzida por carragenina (p<0,001). Portanto, p?de-se concluir que a veicula??o da CS atrav?s de um sistema microemulsionado mostrou-se como uma alternativa interessante para expandir o uso desse flavonoide como um f?rmaco no tratamento da dor inflamat?ria. / Chrysin (5,7-Dihydroxyflavone) belongs to the flavone class of flavonoids. It is found naturally in honey, propolis and various plant species, including species of the gender Pelargonium, Passiflora and the family Pinaceae. Chrysin (CS) is currently marketed as a dietary supplement and, like other flavonoids, also exhibits several pharmacological effects, among which are antinociceptive and anti-inflammatory activity. However, its efficacy has been limited because of its low oral bioavailability. Microemulsions (ME) are modified release systems defined as thermodynamically stable and isotropic translucent systems of two immiscible liquids, usually water and oil, stabilized by an interfacial surfactant film, and often a co-surfactant. ME systems have the ability to solubilize hydrophobic compounds, enhance absorption, bioavailability and stability, enhance efficacy, and reduce the toxicity of incorporated drugs. The aim of this work was the development, characterization and evaluation of the antinociceptive activity of a ME system containing CS. The formulation obtained through a ternary phase diagram was physic-chemically characterized for pH, conductivity and refractive index. Its structural and morphological characteristics were analyzed through dynamic light scattering (DLS) and polarized light microscopy (MLP). Meanwhile, the stability of the formulation was evaluated through centrifugal stress, heating-cooling and freeze-thaw studies. The in vitro release profile was determined using the Franz cell model. The analgesic evaluation was performed through a behavioral test that evaluates the increase of the force threshold on the paw of the mice to analyze the withdrawal reflex through an analgesimeter. In addition, it was determined the ability to prevent the formation of inflammatory cytokines evaluated by ELISA immunoassay. A dose of 25 mg/kg of CS and MECS was administered 30 minutes after carrageenan-induced inflammation. The developed ME consists of 5% isopropyl myristate, 55% water and 40% LAS?, and presented pH compatible with oral administration, conductivity consistent with oil-in-water systems, as well as isotropic behavior. The droplet size distribution was of the monomodal and homogeneous type, with mean droplet sizes of 170.7 ? 5.3 and 158.9 ? 26.7 nm, and negative zeta potential of -16.1 ? 1.9 and -10 ? 2.1, for formulations with and without CS, respectively. ME was stable during the thermal stresses and centrifugation. The in vitro release of MECS followed the zero order kinetic model and prevented the formation of inflammatory cytokines (reduction of TNF? and increase of IL-10, p<0.01), as well as antinociceptive activity in carrageenan-induced inflammation model (p<0.001). Therefore, CS delivery through a microemulsion system proved to be an interesting alternative to expand the use of this flavonoid as a drug in the treatment of inflammatory pain.

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