14 documents found, page 1 of 2
Modification of chicha gum antibacterial activity, ex vivo mucoadhesion, antiox...
Freitas, Alessandra R.; Ribeiro, António J.; Ribeiro, Alessandra B.; Collado-Gonzalez, Maria Del Mar; Silva, Luís R.; Alves, Luís; Melro, ElodieThe aim of the present work was to modify the exuded gum of Sterculia striata tree by an amination reaction. The viscosity and zero potential of the chicha gum varied as a function of pH. The modification was confirmed by X-ray diffraction (XRD), infrared spectroscopy (FTIR), size exclusion chromatography (SEC), zeta potential, thermogravimetric analysis (TG), and differential scanning calorimetry (DSC). Furthe...
Topical Minoxidil-Loaded Nanotechnology Strategies for Alopecia
Santos, Ana Cláudia; Silva, Miguel Pereira da; Guerra, Catarina; Costa, Diana; Peixoto, Diana; Pereira, Irina; Pita, Inês R.; Ribeiro, António J.Androgenetic alopecia (AGA) is a multifactorial and age-related condition characterized by substantial hair loss a ecting both men and women. Conventional treatments include the use of topical minoxidil (MNX) formulations to stimulate hair growth and restore hair condition. However, those treatments are associated with limited performance and a lack of tolerability and compliance due to the emergence of adverse...
Probing insulin bioactivity in oral nanoparticles produced by ultrasonication-a...
Lopes, Marlene A.; Abrahim-Vieira, Bárbara; Oliveira, Claudia; Fonte, Pedro; Souza, Alessandra M. T.; Lira, Tammy; Sequeira, Joana A. D.Alginate-dextran sulfate-based particles obtained by emulsification/internal gelation technology can be considered suitable carriers for oral insulin delivery. A rational study focused on the emulsification and particle recovery steps was developed in order to reduce particles to the nanosize range while keeping insulin bioactivity. There was a decrease in size when ultrasonication was used during emulsificatio...
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 release from alginate microspheres reinforced with dextran sulfate
Silva, Catarina M.; Ribeiro, António J.; Veiga, Francisco; Sousa, Adriano deIn a previous study, insulin was efficiently encapsulated in alginate microspheres using an emulsification /internal gelation process. However, these microspheres showed a high insulin release at gastric pH, exposing the protein to the harsh conditions of the stomach. In this study, our attempt was to improve insulin release profile by reinforcing the alginate matrix with dextran sulfate (DS). The size distribu...
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), ...