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- Risperidone release from solid lipid nanoparticles (SLN): validated HPLC method and modelling kinetic profilePublication . Silva, Ana Catarina; Lopes, Carla Martins; Fonseca, J.; Soares, M.E.; Santos, D.; Souto, Eliana B.; Ferreira, D.A simple reverse-phase (RP) high performance liquid chromatography (HPLC) method was developed and validated, according to the International Harmonisation Guidelines (ICH), for the determination of risperidone (RISP) from solid lipid nanoparticles (SLN). Chromatographic runs were performed on a RP-C18 column, using an isocratic mobile phase of methanol, acetate buffer (0.05 M; pH 4.6) and triethylamine (60:40:0.02, v/v/v). The flow rate was 1 ml/min, the run time was 10 min and the RISP absorbance was measured at 280 nm, using UV detection. A linear response was obtained for a RISP concentration range of 0.25 - 10.00 g/ml (R2 = 0.9996), with a detection and quantification limits of 0.011 and 0.034 g/ml, respectively. The method was shown to be specific, precise at the intra-day (RSD < 0.796%) and inter-day (RSD < 0.331%) levels, and accurate with recoveries between 86.86 - 100.3% (RSD < 0.613%). Method robustness was observed as well. The suitability of the method for RISP quantifications was assessed by the determination of encapsulation parameters (encapsulation efficiency and drug loading) and by studying the RISP release profile from SLN. Kinetic models (zero order, Higuchi, Korsmeyer-Peppas and Baker-Lonsdale) were used to fit the obtained release profile and to predict the in vivo performance of RISP-loaded SLN. A combined pattern of diffusion and erosion release mechanism (anomalous non-Fickian transport) was found for the RISP-loaded SLN, which shows the ability of the system for controlled drug release.
- Pharmaceutical approaches for optimizing oral anti-inflammatory delivery systemsPublication . Lopes, Carla Martins; Oliveira, R.; Silva, Ana CatarinaThe purpose of the present review is to compile the recent literature in the field of anti-inflammatory treatments, with special focus to the state-of-the-art on pharmaceutical approaches for optimizing oral administration. Attending to the drawbacks associated with the use of these types of drugs, the development of oral modulated release formulations is highly desirable in order to achieve improved therapeutic efficacy and patient compliance. Several technological systems and their advantages in modulated and targeted drug releases (gastroretention or colonic release) have been described: matrix systems, coated dosage forms, osmotic pressure based formulations, prodrugs, colloidal carriers, microparticles and other carriers. These new approaches seem to be promising and have been considered by pharmaceutical companies.
- 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.
- Lipid-based nanocarriers as an alternative for oral delivery of poorly water - soluble drugs: peroral and mucosal routesPublication . Silva, Ana Catarina; Santos, D.; Ferreira, D.; Lopes, Carla MartinsThe hydrophobic character of most drug molecules and their potential for degradation under the hostile environment of the gastrointestinal tract (GIT) constitutes the main obstacle in the development of a successful oral drug delivery system, since these are related to limitations of bioavailability and absorption processes. However, according to the advantages of the oral route, alternative ways of drug administration in the oral cavity should be considered. In this context, it is essential to have a systematic knowledge of the GIT and the oral cavity components, for a better understanding of the processes taking place during the oral administration of drugs. This review gives an overview of those anatomical and physiological features and elucidates about the current approaches employed to enhance the bioavailability of oral poorly water-soluble drugs. Strategies including the uses of lipid-based nanocarriers, such as nanoemulsions, liposomes and lipid nanoparticles are discussed, considering their ability to improve solubility, dissolution kinetics, absorption and, consequently, biopharmaceutical properties. Some toxicological concerns are also highlighted.
- Advances in pharmaceutical biotechnologyPublication . Silva, Ana Catarina; Lopes, Carla Martins; Lobo, José M.S.; Amaral, Maria H.
- 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.
- Miconazole-loaded Nanostructured Lipid Carriers (NLC) for local delivery to the oral mucosa: improving antifungal activityPublication . Mendes, A.I.; Silva, Ana Catarina; Catita, José; Cerqueira, Fátima; Gabriel, C.; Lopes, Carla MartinsMiconazole is a widely used antifungal agent with poor aqueous solubility, which requires the development of drug delivery systems able to improve its therapeutic activity. For this purpose, a miconazole-loaded nanostructured lipid carriers (NLC) dispersion was prepared and characterized. Further, the dispersion was used to prepare a NLC-based hydrogel formulation proposed as an alternative system to improve the local delivery of miconazole to the oral mucosa. NLC dispersion showed particles in the nanometer range (≈200 nm) with low polidispersity index (<0.3), good physical stability and high encapsulation efficiency (>87%). A controlled miconazole release was observed from NLC and NLCbased hydrogel formulations, in contrast to a commercial oral gel formulation, which demonstrated a faster release. Additionally, it was observed that the encapsulation of miconazole in the NLC improved its antifungal activity against Candida albicans. Therefore, it was demonstrated that the encapsulation of miconazole in NLC allows for obtaining the same therapeutic effect of a commercial oral gel formulation, using a 17-fold lower dose of miconazole.
- Sistemas semissólidos à base de nanopartículas lipídicasPublication . Garcês, Alexandra; Lopes, Carla Martins; Silva, Ana CatarinaAs nanopartículas lipídicas foram desenvolvidas no início dos anos 90 e, atendendo às vantagens que apresentam comparativamente a outros sistemas coloidais, têm-se demonstrado muito promissoras, tanto para uso cosmético como farmacêutico. No entanto, atualmente apenas existem comercializados produtos cosméticos à base de nanopartículas lipídicas, o que pode ser justificado pelas restrições regulamentares relacionadas com a introdução de medicamentos no mercado, Existem dois tipos de nanopartículas: as nanopartículas de lípidos sólidos (Solid Lipid Nanoparticles, SLN) e os vetores lipídicos nanoestruturados (Nanostructured Lipid Carriers, NLC), consistindo ambos em dispersões aquosas de nanopartículas sólidas. A baixa viscosidade destes sistemas dificulta a sua aplicação tópica. Neste contexto, têm sido desenvolvidas várias formulações semissólidas à base de nanopartículas lipídicas para aplicação tópica, nomeadamente cutânea, ocular, nasal e vaginal. A primeira parte deste trabalho consiste numa revisão bibliográfica relativa ao estado da arte dos sistemas semissólidos à base de nanopartículas lipídicas, para uso farmacêuticos e cosmético, baseada nos estudos realizados por diversos autores entre 2012 e 2016. Na segunda parte, são apresentados resultados do trabalho experimental relativo ao desenvolvimento e caraterização de uma formulação semissólida à base de nanopartículas lipídicas.
- Nucleic acids delivery systems: a challenge for pharmaceutical technologistsPublication . Silva, Ana Catarina; Lopes, Carla Martins; Lobo, José M. Sousa; Amaral, M. HelenaNucleic acids (NA) therapies, including therapy with genes, aptamers or antisense oligonucleotides, have been showing promising results, especially in the treatment of severe diseases (e.g. cancer and AIDS). Nevertheless, the full success of medical treatments requires efficient achievement of the therapeutic target and also the safety and effectiveness of the pharmaceutical system. NA are not very efficient when administered alone, which means that the use of appropriate methods for in vivo transfection of these molecules into targeted cells is fundamental. Examples of these techniques are the use of viral and non-viral vectors to transfer the NA to the cells nucleus. Despite viral vectors have been demonstrating superior effectiveness for NA transfer, some drawbacks have been pointed out, which focused the research in the non-viral vectors. However, the development of effective NA delivery systems remains a challenge for pharmaceutical technologists, mainly because of their in vivo failure, which hinders their clinical application. In this review article we address the characteristics of NA molecules and their respective limitations for formulation and administration. An update on the state of the art related to the latest and outstanding developments from the in vivo applications of NA viral and non-viral delivery systems is also presented. From this review, we can conclude that there is a lack of research regarding pre-clinical studies in specific animal models of disease, which is required for further human clinical trials and for their use in clinics.
- 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.