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Nanoparticulate biopolymers deliver insulin orally eliciting pharmacological re...
Reis, Catarina P.; Veiga, Francisco J.; Ribeiro, António J.; Neufeld, Ronald J.; Damgé, ChristianeThe aim of this study was to characterize and evaluate a novel oral insulin nanoparticulate system based on alginate-dextran sulfate core, complexed with a chitosan-polyethylene glycol-albumin shell. Insulin-loaded nanospheres (25, 50, 100 IU/kg) administered orally to diabetic rats reduced glycemia in a dose dependent manner. This effect lasted over 24 h with a maximal effect after 14 h. Nanospheres increased ...
Polyelectrolyte Biomaterial Interactions Provide Nanoparticulate Carrier for Or...
Reis, Catarina Pinto; Ribeiro, António J.; Veiga, Francisco; Neufeld, Ronald J.; Damgé, ChristianeNanospheres are being developed for the oral delivery of peptide-based drugs such as insulin. Mucoadhesive, biodegradable, biocompatible, and acid-protective biomaterials are described using a combination of natural polyelectrolytes, with particles formulated through nanoemulsion dispersion followed by triggered in situgel complexation. Biomaterials meeting these criteria include alginate, dextran, chitosan, an...
Nanoparticulate delivery system for insulin: Design, characterization and in vi...
Reis, Catarina Pinto; Ribeiro, António J.; Houng, Simone; Veiga, Francisco; Neufeld, Ronald J.Insulin-loaded alginate-dextran nanospheres were prepared by nanoemulsion dispersion followed by triggered in situ gelation. Nanospheres were characterized for mean size and distribution by laser diffraction spectroscopy and for shape by transmission electron microscopy. Insulin encapsulation efficiency and in vitro release were determined by Bradford protein assay and bioactivity determined in vitro using a ne...
Alginate microparticles as novel carrier for oral insulin delivery
Reis, Catarina Pinto; Ribeiro, António J.; Neufeld, Ronald J.; Veiga, FranciscoAlginate microparticles produced by emulsification/internal gelation were investigated as a promising carrier for insulin delivery. The procedure involves the dispersion of alginate solution containing insulin protein, into a water immiscible phase. Gelation is triggered in situ by instantaneous release of ionic calcium from carbonate complex via gentle pH adjustment. Particle size is controlled through the emu...
Oral Bioavailability of Insulin Contained in Polysaccharide Nanoparticles
Sarmento, Bruno; Ribeiro, António; Veiga, Francisco; Ferreira, Domingos; Neufeld, RonaldThe pharmacological activity of insulin-loaded dextran sulfate/chitosan nanoparticles was evaluated following oral dosage in diabetic rats. Nanoparticles were mucoadhesive and negatively charged with a mean size of 500 nm, suitable for uptake within the gastrointestinal tract. Insulin association efficiency was over 70% and was released in a pH-dependent manner under simulated gastrointestinal conditions. Orall...
Nanoencapsulation II. Biomedical applications and current status of peptide and...
Reis, Catarina Pinto; Neufeld, Ronald J.; Ribeiro, António J.; Veiga, FranciscoThe concept of polymeric nanoparticles for the design of new drug delivery systems emerged a few years ago, and recent rapid advances in nanotechnology have offered a wealth of new opportunities for diagnosis and therapy of various diseases. Recent progress has made possible the engineering of nanoparticles to allow the site-specific delivery of drugs and to improve the pharmacokinetic profile of numerous compo...
Nanoencapsulation I. Methods for preparation of drug-loaded polymeric nanoparti...
Reis, Catarina Pinto; Neufeld, Ronald J.; Ribeiro, António J.; Veiga, FranciscoPolymeric nanoparticles have been extensively studied as particulate carriers in the pharmaceutical and medical fields, because they show promise as drug delivery systems as a result of their controlled- and sustained-release properties, subcellular size, and biocompatibility with tissue and cells. Several methods to prepare nanoparticles have been developed during the last two decades, classified according to ...
Development and Comparison of Different Nanoparticulate Polyelectrolyte Complex...
Sarmento, Bruno; Martins, Susana; Ribeiro, António; Veiga, Francisco; Neufeld, Ronald; Ferreira, DomingosThe overall objective of our research is to produce polyanion/chitosan nanoparticulate oral delivery systems for insulin. Specific objectives of the present study were to study dextran sulfate or alginate complexation with chitosan on mean particle size, insulin association efficiency, loading capacity and release profile. Nanoparticles were formed by ionotropic complexation and coacervation between polyanions ...
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