Encontrados 11 documentos, a visualizar página 1 de 2
Supercritical solvent impregnation of ophthalmic drugs on chitosan derivatives
Braga, Mara E. M.; Pato, Maria T. Vaz; Silva, Hélio S. R. Costa; Ferreira, Elisabeth I.; Gil, Maria H.; Duarte, Catarina M. M.; Sousa, Hermínio C. deIn this work, three chitosan derivatives (N-carboxymethyl chitosan (CMC), N-carboxybutyl chitosan (CBC) and N-succinyl chitosan (SCC)) were impregnated with flurbiprofen (an anti-inflammatory drug) and timolol maleate (an anti-glaucoma drug), using a supercritical solvent impregnation (SSI) technique (and employing high pressure CO2 and CO2 + EtOH mixtures) in order to develop hydrogel-type ophthalmic drug deli...
Supercritical fluid impregnation of a biocompatible polymer for ophthalmic drug...
Duarte, Ana Rita C.; Simplicio, Ana Luísa; Vega-González, Arlette; Subra-Paternault, Pascale; Coimbra, Patrícia; Gil, M. H.; Sousa, Hermínio C. deSupercritical fluid impregnation was tested to prepare a new ophthalmic drug delivery device. Poly(methylmethacrylate-co-ethylhexylacrylate-co-ethyleneglycoldimethacrylate), P(MMA-EHA-EGDMA) has been proposed by Mariz [M. Mariz, Preparação de uma lente intra-ocular dotada de um sistema de libertação controlada de fármaco, Master Thesis, Universidade de Coimbra, 1999] as a promising matrix to be used for intraoc...
Supercritical antisolvent precipitation of PHBV microparticles
Costa, M. S.; Duarte, Ana Rita C.; Cardoso, M. M.; Duarte, Catarina M. M.The micronization of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) from organic solutions using supercritical antisolvent (SAS) technique has been successfully achieved. SASexperiments were carried out at different operational conditions and microspheres with mean diameters ranging from 3 to 9 mwere obtained. The effect of CO2 and liquid flow, temperature and pressure on particle size and particle size d...
Preparation of acetazolamide composite microparticles by supercritical antisolv...
Duarte, Ana Rita C.; Roy, C.; Gonzalez, A. V.; Duarte, Catarina M. M.; Subra-Paternault, PascaleThe possibility of preparation of ophthalmic drug delivery systems using compressed anti-solvent technology was evaluated. and RL 100 were used as drug carriers, acetazolamide was the model drug processed. Compressed anti-solvent experiments were carried out as a semi-continuous or a batch operation from a liquid solution of polymer(s) + solute dissolved in acetone. Both techniques allowed the recovery of comp...
Sorption and diffusion of dense carbon dioxide in a biocompatible polymer
Duarte, Ana Rita C.; Martins, Carlos; Coimbra, Patrícia; Gil, Maria H. M.; Sousa, Hermínio C. de; Duarte, Catarina M. M.Mass sorption and diffusion coefficients in one acrylate biocompatible copolymer contacted with supercritical (sc) carbon dioxide are reported. Equilibrium solubility of dense carbon dioxide in poly(methylmethacrylate-co-ethylhexylacrylate-co-ethyleneglycoldimethacrylate) (P(MMA-EHA-EGDMA)) was studied by a gravimetric method in a temperature range from 308 to 323 K and a pressure range from 10.0 to 20.0 MPa. T...
Supercritical polymerization and impregnation of molecularly imprinted polymers...
Duarte, Ana Rita C.; Casimiro, T.; Duarte, A. A.; Simplicio, A. L.; Duarte, Catarina M. M.Herein the preparation of molecularly imprinted polymers (MIPs) using supercritical fluid technology is evaluated. Poly(diethylene glycol dimethacrylate), polyDEGDMA, was synthesised in supercritical carbon dioxide (scCO2) using a carboxylic acid end-capped perfluoropolyether oil as stabiliser. Polymerisations were carried out in the presence of different concentrations of two different template drug molecules,...
Preparation of ethylcellulose/methylcellulose blends by supercritical antisolve...
Duarte, Ana Rita C.; Gordillo, M. D.; Cardoso, M. Margarida; Simplicio, A. L.; Duarte, Catarina M. M.The supercritical antisolvent (SAS) techniquewas used to prepare ethyl cellulose/methyl cellulose blends, two biocompatible polymers commonly used as drug carriers in controlled delivery systems. Ethyl cellulose is widely used as a drug carrier. The drug release of the delivery devices can be controlled to some extent by addition of a water-soluble or water swellable polymer, such as methyl cellulose. This lead...
Preparation of controlled release microspheres using supercritical fluid techno...
Duarte, Ana Rita C.; Costa, M. S.; Simplicio, A. L.; Cardoso, M. Margarida; Duarte, Catarina M. M.Ethylcellulose/methylcellulose blends were produced using different precipitation techniques and impregnated with naproxen, a non-steroidal anti-inflammatory drug (NSAID). Solvent-evaporation technique was used not only for the preparation of ethylcellulose/methylcellulose microspheres but also to encapsulate naproxen. Supercritical fluid (SCF) impregnation was also performed to prepare naproxen loaded microsph...
Solubility of Acetazolamide in Supercritical Carbon Dioxide in the Presence of ...
Duarte, Ana Rita C.; Santiago, Susana; Sousa, Hermínio C. de; Duarte, Catarina M. M.Equilibrium solubility of acetazolamide, a carbonic-anhydrase inhibitor, in supercritical carbon dioxide in the presence of a cosolvent was measured by a static analytical method for three mole fractions of ethanol (5, 7.5, and 10) % at 313.0 K from (13.0 to 21.0) MPa and at 323.0 K from (13.0 to 21.0) MPa for a mole fraction of 5% ethanol The presence of a cosolvent (ethanol) was essential for the solubilizati...
A comparison between gravimetric and in-situ spectroscopic methods to measure t...
Duarte, Ana Rita C.; Anderson, L.; Duarte, Catarina M. M.; Kazarian, S. G.In situ ATR-IR spectroscopy was used to simultaneously measure the sorption and swelling of carbon dioxide at high pressures in a biocompatible acrylate copolymer poly(methylmethacrylate-co-ethylhexylacrylate-co-ethyleneglycoldimethacrylate), P(MMA–EHA–EGDMA). The ν3 band of CO2 dissolved in the polymer (at 2335 cm−1) was used to calculate the sorption data and the polymer swelling was determined by analyzing t...
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