Encontrados 11 documentos, a visualizar página 1 de 2
Ultrasonication of insulin-loaded microgel particles produced by internal gelat...
Santos, Ana C.; Cunha, Joana; Veiga, F.; Cordeiro-da-Silva, A.; Ribeiro, Antonio J.Alginate-dextran sulfate (ADS) microgel has been used to protect insulin from gastrointestinal attack and as a carrier to promote insulin permeation through intestinal epithelium. The throughput of ADS submicron particles generation by emulsification/internal gelation is limited by its wide size distribution. The aim of this work was to study the recovery protocol influence on ADS particles through the determi...
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...
Toxicological in vivo studies of an oral insulin nanosystem
Reis, Catarina Pinto; Veiga, Francisco; Nunes, Patrícia; Soares, Ana Francisca; Laranjeira, Tânia; Carvalho, Rui; Jones, John; Figueiredo, Isabel V.http://www.sciencedirect.com/science/article/B6TCR-4PKH640-7G/1/31df064ec957f50aa568d739cd5d7419
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...
Insulin encapsulation in reinforced alginate microspheres prepared by internal ...
Silva, Catarina M.; Ribeiro, António J.; Ferreira, Domingos; Veiga, FranciscoInsulin-loaded alginate microspheres prepared by emulsification/internal gelation were reinforced by blending with polyanionic additive polymers and/or chitosan-coating in order to increase the protection of insulin at simulated gastric pH and obtain a sustained release at simulated intestinal pH. Polyanionic additive polymers blended with alginate were cellulose acetate phtalate (CAP), Eudragit® L100 (EL100), ...
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...
Alginate microspheres prepared by internal gelation: Development and effect on ...
Silva, Catarina M.; Ribeiro, António J.; Figueiredo, Isabel Vitória; Gonçalves, Alexandra Rocha; Veiga, FranciscoRecombinant human insulin was encapsulated within alginate microspheres by the emulsification/internal gelation technique with the objective of preserving protein stability during encapsulation procedure. The influence of process and formulation parameters was evaluated on the morphology and encapsulation efficiency of insulin. The in vitro release of insulin from microspheres was studied under simulated gastro...
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 ...
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