Browsing by Author "Souto, Eliana B."
Now showing 1 - 10 of 22
Results Per Page
Sort Options
- Advances in nanoparticulate carriers for oral peptides and proteins: polymeric vs. lipid nanoparticlesPublication . Silva, Ana Catarina; Santos, D.; Ferreira, D.C.; Souto, Eliana B.
- Cancer nanopharmaceuticals: physicochemical characterization and in vitro/in vivo applicationsPublication . Zielińska, Aleksandra; Szalata, Marlena; Gorczyński, Adam; Karczewski, Jacek; Eder, Piotr; Severino, Patrícia; Cabeda, JM; Souto, Eliana B.; Słomski, RyszardPhysicochemical, pharmacokinetic, and biopharmaceutical characterization tools play a key role in the assessment of nanopharmaceuticals’ potential imaging analysis and for site-specific delivery of anti-cancers to neoplastic cells/tissues. If diagnostic tools and therapeutic approaches are combined in one single nanoparticle, a new platform called nanotheragnostics is generated. Several analytical technologies allow us to characterize nanopharmaceuticals and nanoparticles and their properties so that they can be properly used in cancer therapy. This paper describes the role of multifunctional nanoparticles in cancer diagnosis and treatment, describing how nanotheragnostics can be useful in modern chemotherapy, and finally, the challenges associated with the commercialization of nanoparticles for cancer therapy.
- Cationic solid lipid nanoparticles (cSLN): structure, stability and DNA binding capacity correlation studiesPublication . Doktorovova, S.; Shegokar, R.; Rakovsky, E.; Gonzalez-Mira, E.; Lopes, Carla Martins; Silva, A.M.; Martins-Lopes, P.; Muller, R.H.; Souto, Eliana B.Cationic solid lipid nanoparticles (cSLN) are promising lipid nanocarriers for intracellular gene delivery based on well-known and widely accepted materials. cSLN containing single-chained cationic lipid cetyltrimethylammonium bromide were produced by high pressure homogenization and characterized in terms of(a) particle size distribution by photon correlation spectroscopy (PCS) and laser diffractometry (LD), (b) thermal behaviour using differential scanning calorimetry (DSC) and (c) the presence of various polymorphic phases was confirmed by X-ray diffraction (WAXD). SLN composed of Imwitor 900PTM (IMW) showed different pDNA stability and binding capacity in comparison to those of Compritol 888 ATOTM (COM). IMW-SLN, having z-ave = 138–157 nm and d(0.5) = 0.15–0.158 m could maintain this size for 14 days at room temperature. COM-SLN had z-ave = 334 nm and d(0.5) = 0.42 m on the day of production and could maintain similar size during 90 days. IMW-SLN revealed improved pDNA binding capacity. We attempted to explain these differences by differentinteractions between the solid lipid and the tested cationic lipid.
- EditorialPublication . Sá, Maria José; Souto, Eliana B.; Martins, Luís
- Effect of polymer viscosity on physicochemical properties and ocular tolerance of FB-loaded PLGA nanospheresPublication . Araújo, J.; Vega, E.; Lopes, Carla Martins; Egea, M.A.; Garcia, M.L.; Souto, Eliana B.Poly(lactide-co-glycolide) acid (PLGA) nanospheres incorporating flurbiprofen (FB) were produced by the solvent displacement technique, for ocular applications aiming to avoid/minimize inflammation induced by surgical trauma. In this work, a PLGA of low viscosity has been tested and the results obtained were compared with those previously reported by Vega et al. The physicochemical properties of the developed formulations were evaluated by measuring particle size, zeta potential and FB entrapment efficiency, showing no significant differences. Release studies demonstrated that the formulation produced with PLGA of higher viscosity revealed a slower drug release rate. Stability analysis, for a period of 75 days, was performed using three complementary methods: (i) turbidity experiments using a Turbiscan optical analyzer, (ii) particle size measurements, and (iii) zeta potential analysis. The results revealed long-term physicochemical stability suitability for ophthalmic use, being independent from the polymer viscosity. The ocular tolerance was assessed by an alternative in vitro method to animal experimentation, the HETCAM. For all developed formulations no ocular irritancy has been detected.
- Estado da arte na prestação de cuidados e tratamento da diabetes mellitusPublication . Ramalho, Sancho Miguel Balsa; Souto, Eliana B.; Lopes, Carla MartinsA Diabetes Mellitus é um dos maiores problemas mundiais de Saúde Pública. A Diabetes é uma desordem metabólica de etiologia múltipla, caracterizada por uma hiperglicemia crónica com distúrbios no metabolismo dos hidratos de carbono, lípidos e proteínas, resultantes de deficiências na secreção ou acção da insulina, ou de ambas. O plano de tratamento pode incluir várias estratégias: consciencialização e educação para a adesão à terapêutica, implementação de plano alimentar e recomendações nutricionais, prática de exercício físico, administração de agentes antidiabéticos, insulina e gestão das complicações associadas.
- Glucagon-like peptide 1: biochemistry, secretion and main physiological effectsPublication . Silva, Amélia M.; Lopes, Carla Martins; Misler, Stanley; Cooper, Gregory D.; Andreani, Tatiana; Souto, Eliana B.O “Glucagon-like peptide 1” (GLP-1), hormona produzida nas células-L intestinais por processamento diferencial do proglucagon, é libertado após ingestão de alimentos. Efeitos de GLP- 1 observam-se, essencialmente, a nível gastrintestinal e pancreático resultando da sua acção directa, ligação ao receptor nas células alvo, ou indirecta, por regulação parácrina. Pelo seu papel na regulação da ingestão de alimentos e na secreção de insulina induzida por glicose, agonistas do receptor de GLP-1 são alvo de estudos para a terapia da obesidade e diabetes. The peptide hormone Glucagon-like peptide 1 (GLP-1), produced in the intestinal L-cells by differential processing of proglucagon, is secreted in response to meal intake. GLP-1 affects various systems, the gastrointestinal and pancreatic systems being the best studied, either by direct binding to the GLP-1 receptor, at the target-cells surface, or indirectly as a result of paracrine regulation. Because of GLP-1’s roles, in augmenting glucose-induced insulin secretion and modulating food intake, currently GLP-1 receptor agonists are being studied for diabetes and obesity therapy.
- Improving oral absorption of samon calcitonin by trimyristin lipid nanoparticlesPublication . Martins, S.; Silva, Ana Catarina; Ferreira, D.C.; Souto, Eliana B.Solid lipid nanoparticles (SLN) composed of trimyristin (solid lipid) and poloxamer 407 (surfactant) were prepared by a w/o/w emulsion technique for the incorporation of Salmon calcitonin, and further explored as protein carriers for oral delivery. Trimyristin SLN showed a mean size diameter of 200 nm with an association efficiency for calcitonin of approx. 86%. The morphology of SLN was investigated by cryo-SEM and by AFM, revealing spheroid shape SLN with a smooth surface. The in vitro release of calcitonin occurred for a period of 8 h, under both gastric and intestinal simulated pH conditions, predicting suitable properties for oral administration. The pharmacological activity of the protein was evaluated following oral dosage of calcitonin-loaded SLN in rats. SLN lowered the basal blood calcium levels by up to 20% with 500 IU/kg dose sustaining hypocalcaemia over 8 h. The results indicate that incorporation of Salmon calcitonin into trimyristin SLN is a key factor for the improvement of the efficiency of such carriers for oral delivery of proteins.
- Lipid nanoparticle mediated drug delivery for safer cancer treatment: example of paclitaxelPublication . Doktorovova, Slavomira; Lopes, Carla Martins; Souto, Eliana B.Os vectores coloidais de natureza lipídica têm atraído particular atenção para o desenvolvimento de terapias mais seguras e eficazes aplicadas a várias doenças. As vantagens da utilização das nanopartículas lipídicas são exemplificadas utilizando o paclitaxel, um anticancerígeno particularmente interessante para o desenvolvimento de novas formas farmacêuticas mais adequadas para o tratamento do cancro. De facto, este fármaco apresenta problemas de insolubilidade aquosa e sérios efeitos secundários concomitantes à administração da forma farmacêutica convencional (Taxol). Este artigo apresenta uma revisão das razões para a reformulação do paclitaxel e sumariza as vantagens de novas formas farmacêuticas contendo nanopartículas lipídicas para a administração deste anticancerígeno. Colloidal carriers composed of lipids attract much attention in the development of safer and more effective therapy of various diseases. The advantages of lipid-based nanoparticles are illustrated on the example of paclitaxel, a challenging chemotherapeutic drug for the development of a novel and more suitable dosage form for cancer treatment. Paclitaxel is known for its water insolubility and serious side effects when administered by its conventional formulation (Taxol). This paper reviews the reasons of further re-formulation of Paclitaxel and summarizes the achievements of lipid nanoparticle-based formulations of this drug.
- Miméticos do “glucagon-like peptide-1” (GLP-1) e o seu potencial farmacêutico no controlo da diabetes tipo 2 e da obesidadePublication . Andreani, Tatiana; Souto, Eliana B.; Silva, Amélia M.; Lopes, Carla MartinsA diabetes mellitus do tipo 2 é caracterizada pela resistência à insulina e pela disfunção das células β do pâncreas. Os péptidos gastrintestinais, “gastric inhibitory polypeptide” (GIP) e “glucagon-like peptide-1” (GLP-1), são hormonas incretinas que estimulam, maioritariamente, a produção de insulina pós-prandial. Formulações contendo GLP-1 possuem um grande potencial no tratamento desta doença. Porém, o GLP-1 é eficaz apenas quando administrado por via parentérica. Para o tratamento da diabetes mellitus tipo 2 são usados análogos do GLP‑ 1 ou miméticos da incretina os quais são eficazes por via subcutânea. The pathogenesis of diabetes mellitus type 2 includes insulin resistance and progressive β-cell dysfunction. The gastrointestinal peptides, gastric inhibitory polypeptide (GIP) and glucagon‑like peptide-1 (GLP-1), are incretin hormones which are responsible for the major part of postprandial insulin secretion. Formulations containing GLP-1 have a great potential in the treatment of diabetes mellitus type 2. Nonetheless, GLP-1 is only efficient by continuous parenteral administration. GLP-1 analogues or incretin mimetics, exendine-4, are active after subcutaneous injection and can be used in the treatment of diabetes mellitus of type 2.
- «
- 1 (current)
- 2
- 3
- »