Contribution à l'étude des gels à base de nanoémulsion : formulations et caractérisation rhéologique

Les nanoémulsions sont des systèmes dispersés constitués de gouttelettes d’une centaine de nanomètres, composés de deux phases non miscibles stabilisées avec des agents tensioactifs, dans le but d’obtenir un système physico-chimique stable. Les formulations de nanoémulsions offrent divers avantages tels que la possibilité d’administration de médicaments à faible solubilité, d'agents de diagnostics ou biologiques. Elles sont également utilisées pour cibler certains tissus et lésions, et peuvent assurer une libération prolongée de médicaments. De manière générale, la formulation de nanoémulsions peut améliorer la biodisponibilité de médicaments. Dans ce cadre, les objectifs de cette thèse de doctorat sont d’une part d’étudier des formulations de gels constitués de nanoémulsions en l’absence de polymères utilisés habituellement pour la réalisation d’hydrogels et d’autre part de caractériser les hydrogels fabriqués d’un point de vue de leurs propriétés rhéologiques. Les différents paramètres de formulation, composition et nature chimique des composés sont également étudiés de manière à permettre de comprendre leur lien avec les profils de libération de molécules modèles encapsulées.Nanoemulsions are dispersed systems consisting of droplets of around one hundred nanometers, composed of two immiscible phases stabilized with surfactants, in order to obtain a stable physicochemical system.Nanoemulsion formulations offer various advantages such as the ability to deliver low solubility drugs, diagnostic or biological agents. They are also used to target certain tissues and lesions, and can provide sustained drug release. In general, the formulation of nanoemulsions can improve the bioavailability of drugs.In this context, the objectives of this doctoral thesis are on the one hand to study gel formulations made up of nanoemulsions in the absence of polymers usually used for the production of hydrogels and on the other hand to characterize the hydrogels produced. From the point of view of their rheological properties, the various formulation parameters, composition and chemical nature of the compounds are also studied so as to make it possible to understand their link with the release profiles of encapsulated model molecules

Carbon nanotubes from synthesis to in vivo biomedical applications

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In Vivo Evaluation of Miconazole-Nitrate-Loaded Transethosomal Gel Using a Rat Model Infected with <i>Candida albicans</i>

Miconazole nitrate (MCNR), an antifungal drug, is used to treat superficial infections. The objective of the current study was to assess the antifungal effectiveness of MCNR-loaded transethosomal gel (MNTG) against Candida albicans in an in vivo rat model. The outcomes were compared with those of the miconazole nitrate gel (MNG) and marketed Daktarin® cream (2%) based on histopathological and hematological studies. The results of the skin irritation test revealed the safety profile of the MNTG. The MNTG demonstrated the greatest antifungal activity in the histological analysis and the visible restoration of the skin, and the rats revealed an apparent evidence of recovery. Compared to the untreated group, the treated group’s lymphocyte and white blood cells counts increased, but their eosinophil counts decreased. In conclusion, MNTG exhibited the greatest antifungal activity, which might be connected to the improved skin permeability of the transethosome’s nanosized vesicles. Therefore, it could be considered a promising carrier for topical usage and the treatment of cutaneous candidiasis. More clinical research needs to be performed in order to demonstrate its effectiveness and safe usage in humans

Novel Hydrogels Based on the Nano-Emulsion Formulation Process: Development, Rheological Characterization, and Study as a Drug Delivery System

In this study, we present a new type of polymer-free hydrogel made only from nonionic surfactants, oil, and water. Such a system is produced by taking advantage of the physicochemical behavior and interactions between nonionic surfactants and oil and water phases, according to a process close to spontaneous emulsification used in the production of nano-emulsions. Contrary to the classical process of emulsion-based gel formulation, we propose a simple one-step approach. Beyond the originality of the concept, these nanoemulgels appear as very promising systems able to encapsulate and deliver various molecules with different solubilities. In the first section, we propose a comprehensive investigation of the gel formation process and its limits through oscillatory rheological characterization, characterization of the sol/gel transitions, and gel strength. The second section is focused on the follow-up of the release of an encapsulated model hydrophilic molecule and on the impact of the rheological gel properties on the release profiles