Loading...
4 results
Search Results
Now showing 1 - 4 of 4
- Alginate films encapsulating polyphenols for nutraceutical and biomedical applicationsPublication . Lagoa, Ricardo; Vanat, Pavlo; Ferreira, Stefanie; Silva, João; Marques-da-Silva, Dorinda; Ribeiro, Vânia; Vaz, Daniela C.; Barreiros, Fátima; Rodrigues, Joaquim Rui
- Towards the Development of Delivery Systems of Bioactive Compounds With Eyes Set on PharmacokineticsPublication . Silva, João S.; Marques-da-Silva, Dorinda; Lagoa, RicardoDelivery systems carrying natural bioactive compounds for enhanced targeting and controlled release are capturing increasing attention. High loadings and sustained release are common design goals. However, in the case of compounds naturally present in human nutrition and physiology, further efforts are justified to optimize their bioactivity and promote clinical success. In this work, it is proposed a specific attention to the regulation of drug temporal presentation as important factor to obtain novel multifunctional delivery systems meeting higher therapeutic efficiencies. Case studies on the relation between drug release dynamics and biological responses are presented for some major delivery strategies and different bioactive molecules. Pharmacokinetic essential concepts and issues concerning the multi-target mode of action typical of the pharmacological properties of natural compounds are discussed in the perspective of improving the development of efficient drug formulations. Several classes of controlled release systems are considered through the chapter, and laboratory setups for testing films and particulate delivery systems are detailed, as well as the application of models for kinetic analysis. Descriptions are illustrated with experimental results obtained with caffeine and epicatechin in our laboratory. Future investigations will benefit from preclinical and clinical evaluation of the new formulations developed by emerging approaches and tools that are being suggested by diverse authors.
- Bioactivity gradients of cytoprotective and anticancer catechins in skin: Simulation studies for the design of controlled release systemsPublication . Silva, João; Videira, Paula; Lagoa, RicardoDermal delivery of catechins may be an effective approach for protection of skin against inflammation, aging and cancer caused by exposure to radiation and environmental toxicants. Catechins are flavonoid-type polyphenols showing capacity to attenuate UV-induced skin injury, carcinogenesis and melanoma metastasis, but the prevalence of beneficial effects depends on compound concentration. In this work, catechin penetration through the skin was simulated to predict the concentration in different layers: stratum corneum, viable epidermis and dermis. By combining these results with expected dose-effect relationships of the compounds, bioactivity profiles were calculated for relevant skin regions. Since the concentration dependences of catechin capacities to protect dermal fibroblasts and to inhibit melanoma cells (data aggregated from published literature) follow different types of dose-effect curves, bioactivity profiles in the skin can be different, even for the same delivery conditions. This method allows to estimate the delivery conditions (time and concentrations) required to achieve the desired biological/pharmacological activities at critical skin strata, namely, viable epidermis and dermis where metastatic melanoma cells and susceptible fibroblasts localize. The work suggests a framework to support the rational design of controlled release systems of topically applied bioactive compounds in therapeutic and investigative delivery.
- Reassessment of the experimental skin permeability coefficients of polycyclic aromatic hydrocarbons and organophosphorus pesticidesPublication . Silva, João; Marques da Silva, Dorinda; Lagoa, Ricardo