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- 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.
- 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.
- 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.
- Therapeutic strategies for Alzheimer's and Parkinson's Diseases by means of drug delivery systemsPublication . Cunha, S.; Amaral, M.H.; Lobo, J.M. Sousa; Silva, Ana CatarinaAlzheimer's and Parkinson's diseases are prevalent neurodegenerative disorders worldwide, which are essentially related to aging. Within the remarkable era of nanomedicine, nowadays several delivery systems have been suggested to improve the treatment of these disorders, namely, liposomes, micelles, nanoparticles (polymeric, lipid, metallic and inorganic), exosomes, dendrimers and fullerenes. The advantage that has been claimed to these delivery systems is that they facilitate the passage of drugs through the blood brain barrier (BBB), enabling targeting before body degradation, and increasing therapeutic efficacy, comparied to conventional pharmaceutical dosage forms. This review article provides a state of the art regarding the drug delivery systems that have been studied for the treatment of Alzheimer's and Parkinson's diseases. It begins with a brief description of the central nervous system (CNS) and the mechanisms involved in the development of these diseases. Later, some examples of drugs used in the treatment of these neurodegenerative diseases are presented, which are currently available in conventional pharmaceutical dosage forms, and in new drug delivery systems that are under development.
- 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.