Browsing by Author "Lobo, J.M. Sousa"
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- 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.
- Current progresses on nanodelivery systems for the treatment of neuropsychiatric diseases: Alzheimer’s and SchizophreniaPublication . Silva, Ana Catarina; González-Mira, E.; Lobo, J.M. Sousa; Amaral, M.H.Currently Alzheimer's disease and schizophrenia are both well-established neuropsychiatric diseases. Nonetheless, the treatment of these disorders is not unanimous and fully effective. As a consequence, several approaches have been studied to improve patient's conditions. In this context, the development of new drug nanodelivery systems to increase drug bioavailability and reduce adverse effects has been claimed as a good option. Among these systems we focus on the ones that seem to be most promising, such as lipidbased systems (e.g. liposomes, nanoemulsions and lipid nanoparticles), drug nanocrystals, polymeric nanoparticles and micelles. Moreover, the application of these systems by means of alternative administration routes is also discussed. Regardless of the satisfactory results and the associated progresses that have been done in the last years, more studies are required to quickly licence the application of drug nanodelivery systems in human medicines.
- Delivery systems for biopharmaceuticals. Part I: nanoparticles and microparticlesPublication . Silva, Ana Catarina; Lopes, Carla Martins; Lobo, J.M. Sousa; Amaral, M.H.Pharmaceutical biotechnology has been showing therapeutic success never achieved with conventional drug molecules. Therefore, biopharmaceutical products are currently well-established in clinic and the development of new ones is expected. These products comprise mainly therapeutic proteins, although nucleic acids and cells are also included. However, according to their sensitive molecular structures, the efficient delivery of biopharmaceuticals is challenging. Several delivery systems (e.g. microparticles and nanoparticles) composed of different materials (e.g. polymers and lipids) have been explored and demonstrated excellent outcomes, such as: high cellular transfection efficiency for nucleic acids, cell targeting, increased proteins and peptides bioavailability, improved immune response in vaccination, and viability maintenance of microencapsulated cells. Nonetheless, important issues need to be addressed before they reach clinics. For example, more in vivo studies in animals, accessing the toxicity potential and predicting in vivo failure of these delivery systems are required. This is the Part I of two review articles, which presents the state of the art of delivery systems for biopharmaceuticals. Part I deals with polymeric and lipid microparticles and nanoparticles.
- Delivery systems for biopharmaceuticals. Part II: liposomes, micelles, microemulsions and dendrimersPublication . Silva, Ana Catarina; Lopes, Carla Martins; Lobo, J.M. Sousa; Amaral, M.H.Biopharmaceuticals are a generation of drugs that include peptides, proteins, nucleic acids and cell products. According to their particular molecular characteristics (e.g. high molecular size, susceptibility to enzymatic activity), these products present some limitations for administration and usually parenteral routes are the only option. To avoid these limitations, different colloidal carriers (e.g. liposomes, micelles, microemulsions and dendrimers) have been proposed to improve biopharmaceuticals delivery. Liposomes are promising drug delivery systems, despite some limitations have been reported (e.g. in vivo failure, poor long-term stability and low transfection efficiency), and only a limited number of formulations have reached the market. Micelles and microemulsions require more studies to exclude some of the observed drawbacks and guarantee their potential for use in clinic. According to their peculiar structures, dendrimers have been showing good results for nucleic acids delivery and a great development of these systems during next years is expected. This is the Part II of two review articles, which provides the state of the art of biopharmaceuticals delivery systems. Part II deals with liposomes, micelles, microemulsions and dendrimers.
- 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.
- 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.
- 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.
- Medicamentos biológicos - exemplos aprovados em PortugalPublication . Carreiro, A.L.; Lobo, J.M. Sousa; Silva, Ana CatarinaOs medicamentos biológicos são obtidos por processos biotecnológicos que usam organismos vivos (ou parte deles), substratos complexos e diferentes tecnologias de ponta para a obtenção das substâncias ativas. Atualmente, estes medicamentos são uma das maiores fontes de inovação e desenvolvimento da indústria farmacêutica, tendo permitido o tratamento de doenças incuráveis e de doenças cujos tratamentos com medicamentos de síntese não são eficazes. Como exemplos destas doenças temos as oncológicas, hematológicas, reumatológicas, entre outras. Com o fim das patentes dos primeiros medicamentos biológicos aprovados, surgiram os medicamentos biossimilares e, mais tarde, os biobetters, que se tornaram concorrentes dos biossimilares. Na primeira parte deste artigo de revisão é feita uma contextualização sobre os medicamentos biológicos e alguns conceitos relacionados. De seguida, são descritas as etapas cruciais do desenvolvimento dos medicamentos biológicos. Por fim, são apresentados exemplos de classes de medicamentos biológicos aprovados em Portugal e as suas respetivas aplicações clínicas, incluindo as citocinas, os fatores de crescimento hematopoiéticos, as hormonas, os hemoderivados e as enzimas. Atualmente, o número de medicamentos biológicos aprovados em Portugal é extenso e está em constante atualização. Entre as classes abordadas, as com maior número de medicamentos aprovados são as dos fatores de crescimento, das hormonas e dos fatores de coagulação.
- Nose-to-brain delivery of lipid-based nanosystems for epileptic seizures and anxiety crisisPublication . Costa, C.; Moreira, J.N.; Amaral, M.H.; Lobo, J.M. Sousa; Silva, Ana CatarinaEpileptic seizures and anxiety crisis are severe conditions that require fast and effective treatment, targeting the brain. Current emergency antiepiletics and anxiolytics have limited brain bioavailability, following oral, intravenous or rectal administration. This relates with the limited extent at which these drugs bypass the blood brain barrier (BBB). Thereby, the development of strategies that significantly improve the brain bioavailability of these drugs, along with a simple and safe administration by patients, attenuating and/or preventing epileptic seizures or anxiety crisis, are still a major need. In this respect, the nasal/intranasal route has been suggested as a promising strategy for drug targeting to the brain, thus avoiding the BBB. Besides, the use of lipid-based nanosystems, such as solid lipid nanoparticles (SLN) and nanostructured lipid carriers (NLC), liposomes, nanoemulsions and microemulsions, have been demonstrating high efficiency for nose-to-brain transport. This review highlights the potential of using lipid-based nanosystems in the management of epilepsy and anxiety, by means of the nasal/intranasal route. So far, the reported studies have shown promising results, being required more in vivo experiments to further advance for clinical trials. Furthermore, toxicological concerns related to the need of evaluate the impairment on the mucociliary clearance mechanism have been pointed.
- Pessaries containing Nanostructured Lipid Carriers (NLC) for prolonged vaginal delivery of progesteronePublication . Correia, A.; Costa, C.P.; Silva, V.; Silva, R.; Lobo, J.M. Sousa; Silva, Ana CatarinaProgesterone (PRG) plays a crucial role in the female reproductive system, being the vaginal route the most adequate for its administration, as this drug has an extensive hepatic first pass effect. Nonetheless, vaginal PRG dosage forms originate immediate drug release and requires repeated administrations, which is unpleasant. Thereby, it is necessary to develop alternative delivery systems for prolonged vaginal release of PRG. The objective of this work was the development of pessaries for the prolonged vaginal delivery of PRG. Studies began with the preparation of an aqueous dispersion of PRG-loaded NLC (NLC_PRG), followed by the evaluation of its biocompatibility in human immortalized keratinocytes (HaCat cells), using three different methods (neutral red uptake, resazurin reduction and sulforhodamine B assays). Finally, the NLC_PRG was incorporated into pessaries, which were further characterized according to the European Pharmacopoeia to assess their suitability to prolong PRG release through the vaginal route. The results showed that, after preparation, 90% of the NLC_PRG had sizes equal or lower than 315.60 ± 0.01 nm, and an EE of 96.42 ± 0.00%. All the assays used to assess the biocompatibility of NLC_PRG showed the absence of cytotoxicity towards HaCaT cells for concentrations up to 10 μg/mL. In all cytotoxicity assays, a cytotoxic effect was only observed for concentrations equal or higher than 25 μg/mL, which provides high confidence in the obtained results. The outcomes of this study suggest the suitability of using pessaries containing PRG-loaded NLC for sustained drug release, which is an innovative therapeutic strategy and constitutes a promising alternative for the vaginal use of PRG. However, further ex vivo and in vivo studies are needed to fully clarify the pharmacokinetic and toxicological profile before reaching the clinical use.