Geles termorreversíveis na veiculação de fármacos
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Data
2019
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Geles termorreversíveis constituem um potencial sistema para a libertação controlada de fármacos. Estes geles gelificam a determinada temperatura, isto é, quando se encontram a baixas temperaturas comportam-se como soluções e a temperaturas específicas comportam-se como geles, aumentando o tempo de residência do fármaco no alvo. Apresentam-se, portanto, como uma aposta promissora para várias vias de administração de fármacos tais como oftálmica, rectal e aplicação tópica.
O objetivo deste trabalho de campo foi o desenvolvimento e caracterização de quatro hidrogeles termorreversíves usando diferentes composições de polímeros: Poloxamer® F127; F127 com quitosano; F127 com carbómero® 940; F127 com goma xantana.
Os geles foram preparados com base no método “Cold” com algumas adaptações. Os geles depois foram caracterizados em termos de viscosidade, análise térmica e da citotoxicidade geral tendo como referência base o modelo de Sacchamoryces Cerevisiae.
Neste estudo observou-se um aumento de viscosidade proporcional ao aumento da temperatura. Todos os geles se comportaram como soluções a 4°C e como geles a 37°C. Os resultados da análise térmica evidenciaram a transição de estado através dos termogramas obtidos. As imagens obtidas com recurso ao SEM demonstraram a presença de cavidades/poros. Quanto ao estudo da citotoxicidade, este estudo sugere os geles não apresentam citotoxicidade no modelo utilizado.
Concluindo, este trabalho de campo reforça a possível aplicação de geles termoreversíveis como veículo de libertação controlada de fármacos. No futuro irão ser realizados novos passos, incluindo a preparação de nanopartículas e sistemas lipídicos e a sua incorporação nos diferentes geles termorreversíves. Para corroborar estes resultados deverão ainda ser realizados estudos de permeação e adesão in vitro e in vivo bem como de citotoxicidade usando um modelo que inclua outros modelos celulares mais complexos.
Thermo-reversible gels are a potential system for controlled drug delivery. These gels gel at a certain temperature, i.e. when at low temperatures behave as solutions and at specific temperatures behave as gels, increasing the residence time of the drug in the target. They are, therefore, presented as a promising bet for various routes of administration of drugs such as parenteral, ophthalmic, rectal and topical application. The aim of this study, was the development and characterization of four thermoreversible hydrogels using different polymer compositions: Poloxamer® F127; F127 with chitosan; F127 with carbomer® 940; F127 with xanthan gum. The gels were prepared based on the Cold method with some adaptations. The gels were then characterized in terms of viscosity, thermal analysis and general cytotoxicity with reference to the Saccharomyces cerevisiae model. In this study it was observed that a proportional increase in viscosity was observed with the increase in temperature. All gels behaved as solutions at 4 ° C and as gels at 37 ° C. The results of the thermal analysis showed the state transition through the obtained thermograms. The images obtained using SEM showed the presence of cavities / pores. Regarding the study of cytotoxicity, this study suggests gels do not present cytotoxicity in the model used. In conclusion, this experimental study reinforces the application of thermoreversible gels as a vehicle for controlled release of drugs, improving their efficacy. Further steps will be taken in the future, including the preparation of nanoparticles and lipid systems and their incorporation into the different thermoreversive gels. In order to corroborate these results, in vitro and in vivo permeation and adhesion studies as well as cytotoxicity should be performed using a model that includes other more complex cellular models.
Thermo-reversible gels are a potential system for controlled drug delivery. These gels gel at a certain temperature, i.e. when at low temperatures behave as solutions and at specific temperatures behave as gels, increasing the residence time of the drug in the target. They are, therefore, presented as a promising bet for various routes of administration of drugs such as parenteral, ophthalmic, rectal and topical application. The aim of this study, was the development and characterization of four thermoreversible hydrogels using different polymer compositions: Poloxamer® F127; F127 with chitosan; F127 with carbomer® 940; F127 with xanthan gum. The gels were prepared based on the Cold method with some adaptations. The gels were then characterized in terms of viscosity, thermal analysis and general cytotoxicity with reference to the Saccharomyces cerevisiae model. In this study it was observed that a proportional increase in viscosity was observed with the increase in temperature. All gels behaved as solutions at 4 ° C and as gels at 37 ° C. The results of the thermal analysis showed the state transition through the obtained thermograms. The images obtained using SEM showed the presence of cavities / pores. Regarding the study of cytotoxicity, this study suggests gels do not present cytotoxicity in the model used. In conclusion, this experimental study reinforces the application of thermoreversible gels as a vehicle for controlled release of drugs, improving their efficacy. Further steps will be taken in the future, including the preparation of nanoparticles and lipid systems and their incorporation into the different thermoreversive gels. In order to corroborate these results, in vitro and in vivo permeation and adhesion studies as well as cytotoxicity should be performed using a model that includes other more complex cellular models.
Descrição
Orientação: Maria Lídia Palma
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CIÊNCIAS FARMACÊUTICAS, FARMACOLOGIA, SISTEMAS DE LIBERTAÇÃO DE MEDICAMENTOS, PHARMACEUTICAL SCIENCES, PHARMACOLOGY, DRUG DELIVERY SYSTEMS, MESTRADO INTEGRADO EM CIÊNCIAS FARMACÊUTICAS, HIDROGÉIS, HYDROGELS