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- Evaluation of the biocompatibility and skin hydration potential of vitamin E-loaded lipid nanosystems formulations: in vitro and human in vivo studiesPublication . Vaz, S.; Silva, R.; Amaral, M.H.; Martins, E.; Lobo, J.M. Sousa; Silva, Ana CatarinaLipid-based nanosystems, such as nanostructured lipid carriers (NLC) and nanoemulsions (NE) have been described as promising alternatives to conventional formulations for increase skin hydration. Besides, these systems have been used as efficient vehicles for lipophilic molecules that improve skin properties (e.g. vitamin E). In this study, we performed comparative investigations between hydrogels formulations containing vitamin E-loaded NLC (HG-NLCVE) and vitamin E-loaded nanoemulsion (HG-NEVE). The experiments started with particle size measurements, which showed no significant differences between nanoparticles/nanodroplets sizes after incorporation in the hydrogel net (386 nm vs. 397 nm for HG-NLCVE and 402 nm vs. 514 nm for HG-NEVE). Afterwards, in vitro biocompatibility studies in human keratinocytes were carried out, being observed that the lipid-based nanosystems were more cytotoxic for the cells before incorporation in the hydrogel. Finally, the formulations hydration potential and sensory attributes for skin application were evaluated by in vitro occlusion tests and in vivo human experiments. The results showed that the HG-NLCVE exhibited the best occlusive properties, whereas the HG-NEVE performed a faster skin hydration effect. Furthermore, the latter was selected as the most attractive for skin application, although the HG-NLCVE was described as more suitable to obtain a long-lasting effect. This study demonstrated the in vitro and in vivo safety and hydration potential of hydrogels containing vitamin E-loaded lipid-based nanosystems. These results establish a basis to assess the cutaneous use of these systems, despite more in vivo experiments, for longer periods and in more volunteers, are required before commercialization.
- Lipid nanoparticles for the delivery of biopharmaceuticalsPublication . Silva, Ana Catarina; Amaral, M.H.; Lobo, J.M. Sousa; Lopes, Carla MartinsBiopharmaceuticals comprise therapeutic protein-based, nucleic acids and cell-based products. According to their therapeutic success, the clinical use of these products has been growing. Therefore, the development of efficient biopharmaceuticals delivery systems, which overcome their limitations for administration, remains an excellent prospect for pharmaceutical technologists. In this area, lipid nanoparticles have been increasingly recognized as one of the most promising delivery systems, due to their exclusive advantages. However, no clinical biopharmaceutical lipid nanoparticle-based products are yet available. This fact could be explained by the lack or failure of in vivo studies, regarding stability and toxicological concerns, and also by the complex regulatory issues that must be accomplished. The present review article focuses on the different classes of biopharmaceuticals, their characteristics and limitations for administration. A state of the art regarding the use of lipid nanoparticles to improve biopharmaceuticals delivery is presented and a critical prospect of the future directions that should be addressed by pharmaceutical technologists is also discussed.
- Formulations based on Solid Lipid Nanoparticles (SLN) and Nanostructured Lipid Carriers (NLC) for cutaneous use: a reviewPublication . Garcês, A.; Amaral, M.H.; Sousa Lobo, J.M.; Silva, Ana CatarinaCutaneous use of lipid nanoparticles (solid lipid nanoparticles, SLN and nanostructured lipid carriers, NLC) has been showing promising results. These systems consist of low viscosity aqueous dispersions, being usually employed by means of semi-solid formulations with adequate consistency for skin application. This review addresses the cutaneous use of lipid nanoparticles for therapeutic and cosmetic applications. Initially, general information related to pharmaceutical semi-solid formulations is presented. Afterwards, the effects of SLN and NLC on the skin, and technological aspects related to semi-solid systems based on SLN or NLC are described. Finally, the most relevant studies related to the formulations based on SLN and NLC, for cosmetic and therapeutic applications, are reported. Notwithstanding the cutaneous use of SLN and NLC has been proposed for both local and transdermal delivery, the reported studies show promising results only for local application. In this sense, more research is required to better understanding the interaction mechanisms of lipid nanoparticles with skin lipids. Furthermore, the development of standard methods for skin experiments with nanoparticles is necessary.
- Characterization and biocompatibility evaluation of cutaneous formulations containing lipid nanoparticlesPublication . Eiras, F.; Amaral, M.H.; Silva, R.; Martins, E.; Lobo, J.M. Sousa; Silva, Ana CatarinaNanostructured lipid carriers (NLC) are well-known systems that show effectiveness to improve skin hydration, being suggested for cosmetic and dermatological use. Nonetheless, NLC dispersions present low viscosity, which is non-attractive for cutaneous application. To circumvent this drawback, the dispersions can be gelled or incorporated in semisolid systems, increasing the final formulation consistency. In this study, we prepared a hydrogel based on NLC containing vitamin E (HG-NLCVE) and evaluated its suitability for cutaneous application. The experiments started with the HG-NLCVE characterization (organoleptic analysis, accelerated stability, particle size, morphology, pH, texture and rheology). Afterwards, in vitro experiments were carried out, evaluating the formulation biocompatibility (MTT and Neutral Red) and irritant potential (Hen's egg test on the chorioallantoic membrane, HET-CAM) for cutaneous application. The results showed that the HG-NLCVE has adequate features for skin application, is biocompatible and non-irritant. From this study, it was predicted the in vivo irritant potential of the developed formulation, avoiding the need to perform a high number of tests on human volunteers. Regarding vitamin E and NLC potential to improve skin hydration, we suggest that the HG-NLCVE could be used in cosmetic (e.g. moisturizers and anti-aging) or dermatologic (e.g. xerosis and other skin disorders) products.
- Intranasal lipid nanoparticles for the treatment of neurodegenerative diseasesPublication . Cunha, S.; Almeida, H.; Amaral, M.H.; Lobo, J.M. Sousa; Silva, Ana CatarinaBackground: treatments for neurodegenerative diseases are challenging, due to the absence of fully effective medicines. One of the major problems associated to these is the occurrence of non-targeting events, which leads to adverse effects and requires frequent dose administration. Methods: Researches have been performed to develop new drug delivery systems administrated by alternative routes. For example, the direct nose-to-brain delivery of drugs by means of lipid nanoparticles, such as solid lipid nanoparticles (SLN) and nanostructured lipid carriers (NLC), has been showing promising results. Results: Among the advantages of intranasal administration is the avoidance of passing the blood-brain barrier (BBB) to reach the central nervous system (CNS), allowing the direct delivery of drugs to the brain by a noninvasive way, minimizing systemic exposure and prolonging residence time. This review article discusses the advantages of using SLN and NLC for direct nose-to-brain drug delivery. A brief reference to other lipid-based carriers (liposomes, nanoemulsions and microemulsions) is also provided. Conclusion: The benefits of using SLN and NLC for improve nasal drug delivery have been demonstrated by in vitro, ex vivo and in vivo experiments. However, more in vivo animal studies are needed for advance to human clinical trials and reach clinics.