Matrizes híbridas siloxano-poliéter incorporadas com argila montmorilonita para liberação controlada de fármaco
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Data
2014-07-22
Autores
Jesus, Celso Ricardo Nogueira [UNESP]
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
A presente tese teve como propósito preparar e caracterizar nanocompósitos formados por híbridos siloxano-poliéter com a incorporação de argila em diferentes teores, para a utilização no controle da liberação do diclofenaco de sódio. Como fase inorgânica do híbrido foi utilizado o (3-isocianatopropil)trietoxisilano (IsoTreos) e como fase orgânica foi utilizado um polímero modificado, o poli(óxido)etileno de massa molar 1900 g/mol. Foram utilizados 3 tipos de argila comercialmente conhecidas como Cloisite®, Cloisite 20A® e Cloisite 30B®, com o intuito de aproveitar suas propriedades de barreira de difusão no controle do perfil de liberação do fármaco. Tanto a argila como o diclofenaco de sódio foram incorporados durante as etapas de hidrólise e policondensação. A estrutura nanoscópica dos xerogéis foi analisada por espalhamento de raios-X a baixos ângulos (SAXS) e as propriedades de liberação do fármaco por espectroscopia UV-visível. A intercalação ou esfoliação das lamelas das argilas foi investigada por difração de raios X (XRD). As técnicas de calorimetria diferencial de varredura (DSC) e análise termogravimétrica e termodiferencial (TG-DTA) forneceram informações a respeito da estabilidade térmica, do comportamento da cristalização e fusão dos nanocompósitos. Difratogramas de raios X dos nanocompósitos incorporados com a Cloisite® indicam aumento do espaço interlamelar da argila após a formação dos híbridos, levando a estruturas intercaladas, independentemente do teor de argila utilizado. Nanocompósitos contendo a argila Cloisite 30B®, incorporada com um modificador polar, levaram a estruturas esfoliadas, enquanto os que contem a argila Cloisite 20A®, incorporada com um modificador apolar, apresentaram estruturas intercaladas. Pelas curvas de DSC foi possível mostrar que os híbridos contendo argila apresentaram um maior grau de cristalinidade...
In this thesis we intended to prepare and characterize nanocomposites that were obtained from syloxane-polyether containing different amounts of clays, aiming to improve the controlled release properties of sodium diclophenac from these matrixes. The (3- isocyanatepropyl)triethoxysilane (IsoTreos) was used as the inorganic phase and the polyethileneoxide modified polymer, MM 1900g/mol as the organic one. Due to their diffusion barrier properties, three different commercial clays, known as Cloisite®, Cloisite 20A® and Cloisite 30B® were used aiming to improve the release profile of diclofenac. Both the clay and the drug were incorporated during the hydrolysis and condensation steps of samples preparation. The nanoscopic structure of xerogels was analysed by Small-Angle X-Ray Scattering (SAXS) while the release properties of diclofenac were followed by UV-Visible spectroscopy. Intercalation or exfoliation properties of the clay lamellae structure were investigated by X-Ray Diffraction (XRD), while the thermal stability, the fusion and crystallization behaviour of nanocomposites were followed by using differential scattering calorimetry (DSC) and thermal analysis (TG-DTA). Irrespective of the clay amount, the XRD patterns of nanocomposites containing Cloisite® show an increase of the clay interlamellae distance, indicating the formation of intercalated structures. For nanocomposites containing the Cloisite 30B® clay, incorporated by means of a polar modifier, exfoliated structures were observed, while for that prepared with the Cloisite 20A® clay, incorporated using an apolar modifier, intercalated structures were observed. DSC curves have shown that hybrids containing clays present higher fusion point and crystallinity degree than hybrids containing clay and drug. Moreover thermal analysis shows that the clays addition improves the thermal properties of hybrids. The swellling of xerogels was...
In this thesis we intended to prepare and characterize nanocomposites that were obtained from syloxane-polyether containing different amounts of clays, aiming to improve the controlled release properties of sodium diclophenac from these matrixes. The (3- isocyanatepropyl)triethoxysilane (IsoTreos) was used as the inorganic phase and the polyethileneoxide modified polymer, MM 1900g/mol as the organic one. Due to their diffusion barrier properties, three different commercial clays, known as Cloisite®, Cloisite 20A® and Cloisite 30B® were used aiming to improve the release profile of diclofenac. Both the clay and the drug were incorporated during the hydrolysis and condensation steps of samples preparation. The nanoscopic structure of xerogels was analysed by Small-Angle X-Ray Scattering (SAXS) while the release properties of diclofenac were followed by UV-Visible spectroscopy. Intercalation or exfoliation properties of the clay lamellae structure were investigated by X-Ray Diffraction (XRD), while the thermal stability, the fusion and crystallization behaviour of nanocomposites were followed by using differential scattering calorimetry (DSC) and thermal analysis (TG-DTA). Irrespective of the clay amount, the XRD patterns of nanocomposites containing Cloisite® show an increase of the clay interlamellae distance, indicating the formation of intercalated structures. For nanocomposites containing the Cloisite 30B® clay, incorporated by means of a polar modifier, exfoliated structures were observed, while for that prepared with the Cloisite 20A® clay, incorporated using an apolar modifier, intercalated structures were observed. DSC curves have shown that hybrids containing clays present higher fusion point and crystallinity degree than hybrids containing clay and drug. Moreover thermal analysis shows that the clays addition improves the thermal properties of hybrids. The swellling of xerogels was...
Descrição
Palavras-chave
Físico-química, Fármacos, Argila, Espectroscopia de raio X, Polimeros, Ciência dos materiais, Clay
Como citar
JESUS, Celso Ricardo Nogueira. Matrizes híbridas siloxano-poliéter incorporadas com argila montmorilonita para liberação controlada de fármaco. 2014. 143 f. Tese (doutorado) - Universidade Estadual Paulista Júlio de Mesquita Filho, Instituto de Química de Araraquara, 2014.