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Binary Mutual Diffusion Coefficients of Isoniazid Aqueous Solutions at (298.15 ...
Ribeiro, Ana C. F.; Santos, Ana C. G.; Lobo, Victor M. M.; Veiga, Francisco J. B.; Cabral, Ana M. T. D. P. V.; Esteso, Miguel A.; Ortona, OrnellaBinary mutual diffusion coefficients measured by the Taylor dispersion method in two different laboratories (University of Naples, Federico II, Italy, and University of Coimbra, Portugal) are reported for aqueous solutions of isoniazid at concentrations from (0.000 to 0.100) mol·dm−3 and at two temperatures (298.15 and 310.15) K. The hydrodynamic radii for the isoniazid in aqueous solution are calculated from t...
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 ...
Some Transport Properties of γ-Cyclodextrin Aqueous Solutions at (298.15 and 31...
Ribeiro, Ana C. F.; Santos, Cecília I. A. V.; Valente, Artur J. M.; Ascenso, Osvaldo S.; Lobo, Victor M. M.; Burrows, H. D.; Cabral, Ana M. T. D. P. V.Values of binary mutual diffusion (interdiffusion) coefficients, obtained by using the Taylor dispersion method, for aqueous solutions of γ-cyclodextrin in the concentration range from (0.002 to 0.010) mol·dm−3 and temperatures (298.15 and 310.15) K are reported. From these experimental results, the hydrodynamic radius values for the γ-cyclodextrin are estimated. Also, the measured diffusion coefficients are us...
Cyclodextrin multicomponent complexation and controlled release delivery strate...
Ribeiro, Laura S. S.; Falcão, Amílcar C.; Patrício, João A. B.; Ferreira, Domingos C.; Veiga, Francisco J. B.In the present work, to maintain a suitable blood level of vinpocetine (VP) for a long period of time, VP-cyclodextrin-tartaric acid multicomponent complexes were prepared and formulated in hydroxypropylmethylcellulose matrix tablets. In vitro and in vivo performances of these formulations were investigated over a VP immediate release dosage form. Solubility studies were performed to evaluate the drug pH solubi...
Evaluation of host-guest complex formation between a benzimidazolic derivative ...
Figueiras, Ana; Ribeiro, Laura; Torres-Labandeira, J.; Veiga, Francisco J.Abstract Interactions between a benzimidazolic derivative, omeprazole (OME), beta-cyclodextrin (ßCD) and a chemically modified ßCD, methyl-beta-cyclodextrin (MßCD) were investigated in aqueous solution by UV-VIS spectroscopy and in solid state by differential scanning calorimetry (DSC). Phase solubility studies were used to evaluate the complexation in aqueous solution. The two solubility diagrams obtained wer...
Cyclodextrin multicomponent complexation and controlled release delivery strate...
Ribeiro, Laura S. S.; Falcão, Amílcar; Patrício, João A. B.; Ferreira, Domingos C.; Veiga, Francisco J. B.In the present work, to maintain a suitable blood level of vinpocetine (VP) for a long period of time, VP-cyclodextrin-tartaric acid multicomponent complexes were prepared and formulated in hydroxypropylmethylcellulose matrix tablets. In vitro and in vivo performances of these formulations were investigated over a VP immediate release dosage form. Solubility studies were performed to evaluate the drug pH solubi...
Multicomponent complex formation between vinpocetine, cyclodextrins, tartaric a...
Ribeiro, Laura; Carvalho, Rui A.; Ferreira, Domingos C.; Veiga, Francisco J. B.This work deals with multicomponent complex formation of vinpocetine (VP) with [beta]-cyclodextrin ([beta]CD), sulfobutyl ether [beta]-cyclodextrin (SBE[beta]CD) and tartaric acid (TA), in the presence or absence of water-soluble polymers, in aqueous solution. Complexation was monitored by phase-solubility and proton nuclear magnetic resonance (1H NMR) studies. TA demonstrated a synergistic effect on VP solubil...
The Cyclodextrins as Modelling Agents of Drug Controlled Release
Fernandes, Catarina M.; Veiga, Francisco J. B.The controlled release of nicardipine (NC) was achieved by hybridizing its hydrophilic and hydrophobic cyclodextrin (CDs) complexes, i.e., those with hydroxypropyl-ß-cyclodextrin (HPßCD) andtriacetyl-ß-cyclodextrin (TAßCD),respectively. 1H-nuclearmagnetic resonance (1H-NMR) was performed to examine the interaction between both CDs and NC in solution. The solid complexes of NC : HPßCD and NC : TAßCD were prepare...
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