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Development of decorated liposomes for ocular delivery of triamcinolone acetonide
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Os corticosteroides têm sido utilizados por muitos anos para tratar inúmeras condições oftálmicas. O acetonido de triamcinolona é um corticosteroide usado para minimizar muitas condições inflamatórias que afetam os olhos e a pele. Os lipossomas são sistemas avançados de veiculação de fármacos que geralmente transportam fármacos hidrofóbicos a um alvo específico, melhorando a sua farmacodinâmica.
O objetivo deste trabalho foi produzir e caracterizar lipossomas de acetonido de triamcinolona contendo Soluplus e vitamina E-TPGS, para aplicação oftálmica. Esta estratégia foi adotada para melhorar a solubilidade do fármaco e, por outro lado, para estabilizar a bicamada fosfolipídica. O método escolhido para produzir lipossomas foi a hidratação do filme lipídico e posteriormente foi efetuado um planeamento experimental de forma a rastrear as condições de otimização das formulações. As amostras foram submetidas a métodos de caracterização físico-química como a eficiência de encapsulação, tamanho de partícula e índice de polidispersão, análise calorimétrica e finalmente o teste de libertação de fármaco in vitro. Os resultados revelaram que a adição do tensioativo Soluplus e vitamina E-TPGS aumentou a solubilização do fármaco e a estabilidade do sistema lipossomal. Também foi possível verificar que os lipossomas conferiram uma taxa de libertação superior do que o fármaco na sua forma livre, atingindo percentagens próximas de 80%. A eficiência de encapsulação, por outro lado, não foi a esperada, já que não atingiu sequer 50% e possivelmente não obtivemos uma população homogénea de SUVs, mas uma mistura de MLVs e LUVs, já que os valores de índice de polidispersão estiveram abaixo de 0.50 ± 0.1 e a dispersão do tamanho de partícula entre 300 e 800 nm.
Em conclusão, é fundamental continuar a investigar a adequabilidade da hidratação do filme lipídico como método de produção em larga escala de lipossomas, analisando criticamente os erros ocorridos no processo e repetindo os ensaios com diferentes formulações, em que sejam avaliados outros ingredientes e proporções. Apesar dos dados serem preliminares, o comportamento dos lipossomas parece melhorar a libertação e estabilidade do acetonido de triamcinolona na forma lipossomal.
Corticosteroids have been used for many years to treat several ophthalmic conditions. Triamcinolone acetonide is a corticosteroid used to minimize many inflammatory conditions that affects the eyes and skin. Liposomes are advanced drug delivery systems that usually carry hydrophobic drugs to a specific target, improving pharmacodynamics. The aim of this work was to produce and characterize triamcinolone acetonide-loaded liposomes for ophthalmic application decorated with SoluPlus and vitamin E-TPGS. This strategy was, on the one hand, to increase the drug solubilization in water and, on the other hand to stabilize the phospholipid bilayer. The liposome production method chosen was the thin film hydration and after all, a design of experiment was carried out to track down the conditions for optimizing the formulations. The samples were submitted to physicochemical characterization methods such as encapsulation efficiency, particle size and dispersion index, calorimetric analysis and finally the in vitro drug release test. The results showed that the addition of the surfactant Soluplus and vitamin E-TPGS rised the drug solubilization and the stability of the liposomal system. It can also be seen that the liposomes have a higher release rate to the outside than the free form, making it to percentages even close to 80%. The encapsulation performance, on the other hand, was not as expected, since it didn't get to 50% and possibly, a homogeneous population was not obtained but instead, a mixed population of MLVs and LUVs, since the dispersion index values were above 0.50 ± 0.1 and the disparity in particle sizes between 300 and 800 nm. In conclusion, it is important to keep studying the suitability of thin film hydration as a method for large-scale liposome production, critically analyzing errors in the process performed, as well as repeating the tests with different formulations where other ingredients are scanned. Although the data is preliminary, the behavior of the liposomes seems to improve the release and stability of liposomal triamcinolone acetonide.
Corticosteroids have been used for many years to treat several ophthalmic conditions. Triamcinolone acetonide is a corticosteroid used to minimize many inflammatory conditions that affects the eyes and skin. Liposomes are advanced drug delivery systems that usually carry hydrophobic drugs to a specific target, improving pharmacodynamics. The aim of this work was to produce and characterize triamcinolone acetonide-loaded liposomes for ophthalmic application decorated with SoluPlus and vitamin E-TPGS. This strategy was, on the one hand, to increase the drug solubilization in water and, on the other hand to stabilize the phospholipid bilayer. The liposome production method chosen was the thin film hydration and after all, a design of experiment was carried out to track down the conditions for optimizing the formulations. The samples were submitted to physicochemical characterization methods such as encapsulation efficiency, particle size and dispersion index, calorimetric analysis and finally the in vitro drug release test. The results showed that the addition of the surfactant Soluplus and vitamin E-TPGS rised the drug solubilization and the stability of the liposomal system. It can also be seen that the liposomes have a higher release rate to the outside than the free form, making it to percentages even close to 80%. The encapsulation performance, on the other hand, was not as expected, since it didn't get to 50% and possibly, a homogeneous population was not obtained but instead, a mixed population of MLVs and LUVs, since the dispersion index values were above 0.50 ± 0.1 and the disparity in particle sizes between 300 and 800 nm. In conclusion, it is important to keep studying the suitability of thin film hydration as a method for large-scale liposome production, critically analyzing errors in the process performed, as well as repeating the tests with different formulations where other ingredients are scanned. Although the data is preliminary, the behavior of the liposomes seems to improve the release and stability of liposomal triamcinolone acetonide.
Descrição
Trabalho Final de Mestrado Integrado, Ciências Farmacêuticas, 2024, Universidade de Lisboa, Faculdade de Farmácia.
Palavras-chave
Triamcinolone acetonide. Soluplus Vitamin E-TPGS Liposome Thin film hydration Mestrado Integrado - 2024