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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.
31

DESENVOLVIMENTO E CARACTERIZAÇÃO DE SUSPENSÕES CONTENDO NANOCÁPSULAS DE ADAPALENO COM DIFERENTES NÚCLEOS OLEOSOS

Barrios, Jerusa Goi 30 June 2010 (has links)
Submitted by MARCIA ROVADOSCHI (marciar@unifra.br) on 2018-08-15T13:27:18Z No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Dissertacao_JerusaGoiBarrios.pdf: 2507299 bytes, checksum: b0357f55d1ddf8dd63d987592cf16a6e (MD5) / Made available in DSpace on 2018-08-15T13:27:18Z (GMT). No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Dissertacao_JerusaGoiBarrios.pdf: 2507299 bytes, checksum: b0357f55d1ddf8dd63d987592cf16a6e (MD5) Previous issue date: 2010-06-30 / Acne is one of the most common inflammatory conditions affecting the skin. There are several drugs to treat it, but despite the benefits of these treatments in their free form, there are common side effects to them, especially when applied topically. Among these drugs is the adapalene with comedolitic action and effects on the abnormal process of keratinization and epidermal differentiation, phenomena present in acne vulgaris. This study aimed to prepare polymer nanocapsules of adapalene through the method of interfacial deposition of preformed polymer using different oil cores (tea tree oil and Miglyol®). The suspensions were characterized by determining the pH, particle diameter, polidispersion rate, zeta potential, association rate and dosage of the drug. The stability was determined at different temperatures and under light UVA. In vitro release studies and analysis of mathematical modeling of kinetic release profiles were carried out by comparing suspensions containing adapalene polymer nanocapsules and nanodispersions and without the presence of the polymer. The formulations were stored at room temperature (25 ° C), refrigerator (-4 ° C) and oven (40 ° C) for 3 months and analyzed at 0, 7, 15, 30, 60 and 90 days after preparation. Both suspensions containing Miglyol® polymer nanocapsules (NC-AD-Miglyol®) as the tea tree oil polymer nanocapsules (NC-AD-tea tree oil) showed acidic pH, particle diameter below 300 nm and zeta potential negative. The rate of association of adapalene in the NC-AD-tea tree oil was 95.4% while the NC-AD-Miglyol® was 84.1%. The dosage of the drug showed that the NCAD- tea tree oil exerts a greater stabilizing effect than the other formulations. The shelf life estimated for the NC-AD-tea tree oil was higher when compared to nanodispersion (ND) and NC-AD-Miglyol®. Mathematical modeling showed that the ND and NC-AD-Miglyol® followed a kinetic profile, according to the mono-exponential model with half-lives of 3.53 and 8.43 hours. On the other hand, NC-AD-tea tree oil suspension followed a bi-exponential, model with half-lives of 4.07 hours for the fast phase and 230.6 hours for the sustained phase. Therefore, we can say that the adapalene formulation NC-AD-Miglyol® locates largely more externally in the polymer nanocapsule, while in the NC-AD-tea tree oil, it is dissolved in the oil core of the polymer nanocapsule, suggesting a sustained release. We evaluated the photostability of adapalene nanocoated with Miglyol® oil and tea tree oil under UVA irradiation, and concluded that the nanoencapsulation with tea tree oil increases the stability of the active, offering increased protection it from degradation. In analysis by multiple scattering of light, the suspensions showed a tendency of sedimentation, but the NC-ADMiglyol ® proved to be more likely to destabilization. The validation of the method was satisfactory for all parameters analyzed. Though the results obtained, it can be concluded that the suspension containing NC-AD-tea tree oil showed better physical and chemical characteristics and stability, representing best technological feasibility fot the pharmaceutical area. / A acne é uma das condições inflamatórias mais comuns que afetam a pele. Existem diversos fármacos para o tratamento da acne, porém apesar dos benefícios desses tratamentos na sua forma livre, existem efeitos adversos comuns a eles, principalmente quando aplicados topicamente. Dentre estes fármacos, destaca-se o adapaleno com ação comedolítica e efeitos sobre o processo anormal de queratinização e diferenciação epidérmica, fenômenos presentes na acne vulgar. O presente trabalho teve como objetivo, preparar nanocápsulas poliméricas (NC) de adapaleno através do método de deposição interfacial do polímero pré-formado utilizando diferentes núcleos oleosos (Miglyol® e óleo de melaleuca). As suspensões foram caracterizadas através da determinação do pH, diâmetro de partícula, índice de polidispersão, potencial zeta, taxa de associação e doseamento do fármaco. A estabilidade foi determinada em diferentes temperaturas e frente à luz UVA; estudos de liberação in vitro e análises de modelagem matemática dos perfis cinéticos de liberação foram realizados comparando-se suspensões contendo NC de adapaleno e nanodispersões, sem a presença do polímero. As formulações foram armazenadas em temperatura ambiente (25 °C), geladeira (-4 °C) e estufa (40 °C) durante 3 meses e analisadas nos tempos 0, 7, 15, 30, 60 e 90 dias após preparação. Tanto as suspensões contendo NC com Miglyol® (NC-AD-Miglyol®) como as NC com óleo de melaleuca (NC-AD-Melaleuca) apresentaram pH ácido, diâmetro de partícula inferior a 300 nm e potencial zeta negativo. A taxa de associação do adapaleno na NC-AD-Melaleuca foi de 95,4% enquanto na NC-AD-Miglyol® foi 84,1%. Através do doseamento do ativo, concluiu-se que as NC-AD-Melaleuca exercem efeito estabilizante maior que as demais formulações. O prazo de validade estimado para a NC-AD-Melaleuca foi superior quando comparado à nanodispersão (ND) e a NC-AD-Miglyol®. A modelagem matemática demonstrou que a ND e a NC-AD-Miglyol® seguiram um perfil cinético segundo o modelo monoexponencial com tempo de meia-vida de 3,53 e 8,43 horas, respectivamente. Já a suspensão NC-AD-Melaleuca seguiu modelo biexponencial com tempo de meia-vida para a fase rápida de 4,07 horas e 230,6 horas para a fase sustentada. Pode-se concluir que o adapaleno na formulação NC-AD-Miglyol® encontra-se em grande parte mais externamente nas NC enquanto na NC-AD-Melaleuca, o fármaco encontra-se dissolvido no núcleo oleoso das NC, sugerindo dessa forma, uma liberação sustentada. Avaliou-se a fotoestabilidade do adapaleno nanoencapsulado com Miglyol® e óleo de melaleuca frente à irradiação por UVA e concluiu-se que a nanoencapsulação com óleo de melaleuca aumenta a estabilidade do ativo, protegendo-o da degradação. Em análises por espalhamento múltiplo de luz, as suspensões apresentaram tendência à sedimentação, porém a NC-AD-Miglyol® demonstrou mais probabilidade à desestabilização. A validação da metodologia apresentou resultados satisfatórios para todos os parâmetros analisados. Através dos resultados obtidos, pode-se concluir que a suspensão contendo NC-AD-Melaleuca apresentou melhores características físico-químicas e de estabilidade, representando melhor viabilidade tecnológica para a área farmacêutica.
32

The role of mycorrhizal fungi in nutrient supply and habitat specificity of the rare mycoheterotrophic underground orchid, Rhizanthella gardneri

Bougoure, Jeremy J. January 2009 (has links)
Rhizanthella gardneri (Rogers) is a critically endangered orchid restricted to two isolated regions of south-western Australia. Rhizanthella gardneri is an entirely subterranean mycoheterotrophic species that purportedly forms a tripartite relationship with a mycorrhizal fungus (Ceratobasidiales) that links with an autotrophic shrub of the Melaleuca uncinata complex to acquire nutrients. Whether the rarity of R. gardneri is intrinsic is overshadowed by the recent effect of extrinsic factors that means R. gardneri requires some form of conservation and may also be a viable candidate for restoration. To create an integrated conservation strategy for R. gardneri, reasons for its decline and knowledge of its biological and ecological functioning must be elucidated. This thesis focuses on three key questions; 1) what are the habitat requirements and limitations to R. gardneri survival; 2) what is the identity and specificity of the fungus R. gardneri forms mycorrhizas with; and 3) does R. gardneri form a nutrient-sharing tripartite relationship with a mycorrhizal fungus and autotrophic shrub. Key climate, soil and vegetation characteristics of known R. gardneri habitats were quantified to provide baseline data for monitoring known R. gardneri populations, to better understand how R. gardneri interacts with its habitat, and to identify possible new sites for R. gardneri introduction. Habitats of the two known R. gardneri populations differed considerably in soil chemistry, Melaleuca structure and Melaleuca productivity. Individual sites within populations were relatively similar in all attributes measured while overall Northern and Southern habitats were distinct from each other. These results suggest that R. gardneri can tolerate a range of conditions and may be more widespread than previously thought, given that there are extensive areas of Melaleuca thickets with similar habitat characteristics across south-western Australia. The fungus forming mycorrhizas with R. gardneri was identified, using nuclear ribosomal DNA sequences, as a Rhizoctonia-type fungus within the Ceratobasidiales. All fungi isolated from R. gardneri individuals representative of its currently known distribution were genetically similar, suggesting R. gardneri is highly dependent on this specific fungal species. Given that R. gardneri appears to exclusively associate with a specific fungal species, species-specific molecular primers were designed and used to analyse the fungi’s presence in known and potential R. gardneri habitats. These results 6 suggest that the fungus exists beyond the known R. gardneri habitats and gives hope to finding new populations.
33

The role of mycorrhizal fungi in nutrient supply and habitat specificity of the rare mycoheterotrophic underground orchid, Rhizanthella gardneri

Bougoure, Jeremy J. January 2009 (has links)
Rhizanthella gardneri (Rogers) is a critically endangered orchid restricted to two isolated regions of south-western Australia. Rhizanthella gardneri is an entirely subterranean mycoheterotrophic species that purportedly forms a tripartite relationship with a mycorrhizal fungus (Ceratobasidiales) that links with an autotrophic shrub of the Melaleuca uncinata complex to acquire nutrients. Whether the rarity of R. gardneri is intrinsic is overshadowed by the recent effect of extrinsic factors that means R. gardneri requires some form of conservation and may also be a viable candidate for restoration. To create an integrated conservation strategy for R. gardneri, reasons for its decline and knowledge of its biological and ecological functioning must be elucidated. This thesis focuses on three key questions; 1) what are the habitat requirements and limitations to R. gardneri survival; 2) what is the identity and specificity of the fungus R. gardneri forms mycorrhizas with; and 3) does R. gardneri form a nutrient-sharing tripartite relationship with a mycorrhizal fungus and autotrophic shrub. Key climate, soil and vegetation characteristics of known R. gardneri habitats were quantified to provide baseline data for monitoring known R. gardneri populations, to better understand how R. gardneri interacts with its habitat, and to identify possible new sites for R. gardneri introduction. Habitats of the two known R. gardneri populations differed considerably in soil chemistry, Melaleuca structure and Melaleuca productivity. Individual sites within populations were relatively similar in all attributes measured while overall Northern and Southern habitats were distinct from each other. These results suggest that R. gardneri can tolerate a range of conditions and may be more widespread than previously thought, given that there are extensive areas of Melaleuca thickets with similar habitat characteristics across south-western Australia. The fungus forming mycorrhizas with R. gardneri was identified, using nuclear ribosomal DNA sequences, as a Rhizoctonia-type fungus within the Ceratobasidiales. All fungi isolated from R. gardneri individuals representative of its currently known distribution were genetically similar, suggesting R. gardneri is highly dependent on this specific fungal species. Given that R. gardneri appears to exclusively associate with a specific fungal species, species-specific molecular primers were designed and used to analyse the fungi’s presence in known and potential R. gardneri habitats. These results 6 suggest that the fungus exists beyond the known R. gardneri habitats and gives hope to finding new populations.

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