Encontrados 16 documentos, a visualizar página 1 de 2
Chitosan-based dressings loaded with neurotensin—an efficient strategy to impro...
Moura, Liane I. F.; Dias, Ana M. A.; Leal, Ermelindo C.; Carvalho, Lina; Sousa, Hermínio C. de; Carvalho, EugéniaOne important complication of diabetes mellitus is chronic, non-healing diabetic foot ulcers (DFUs). This study aims to develop and use dressings based on chitosan derivatives for the sustained delivery of neurotensin (NT), a neuropeptide that acts as an inflammatory modulator in wound healing. Three different derivatives, namely N-carboxymethyl chitosan, 5-methyl pyrrolidinone chitosan (MPC) and N-succinyl chi...
Electrospun Drug-Eluting Fibers for Biomedical Applications
Natu, Mădălina V.; Sousa, Hermínio C. de; Gil, Maria H.Electrospinning is a simple and versatile method to produce fibers using charged polymer solutions. As drug delivery systems, electrospun fibers are an excellent choice because of easy drug entrapment, high surface area, morphology control and biomimetic characteristics. Various drugs and biomolecules can be easily encapsulated inside or on fiber surface either during electrospinning or through post-processing ...
In vitro and in vivo evaluation of an intraocular implant for glaucoma treatment
Natu, Mădălina V.; Gaspar, Manuel N.; Ribeiro, Carlos A. Fontes; Cabrita, António M.; Sousa, Hermínio C. de; Gil, M. H.Implantable disks for glaucoma treatment were prepared by blending poly(ɛ-caprolactone), PCL, poly(ethylene oxide)-b-poly(propylene oxide)-b-poly(ethylene oxide) and dorzolamide. Their in vivo performance was assessed by their capacity to decrease intraocular pressure (IOP) in normotensive and hypertensive eyes. Drug mapping showed that release was complete from blend disks and the low molecular weight (MW) PCL...
Effects of drug solubility, state and loading on controlled release in bicompon...
Natu, Mădălina V.; Sousa, Hermínio C. de; Gil, M. H.Bicomponent fibers of two semi-crystalline (co)polymers, poly(ɛ-caprolactone), and poly(oxyethylene-b-oxypropylene-b-oxyethylene), were obtained by electrospinning. Acetazolamide and timolol maleate were loaded in the fibers in different concentrations (below and above the drug solubility limit in polymer) in order to determine the effect of drug solubility in polymer, drug state, drug loading and fiber composi...
Solubility of Irgacure® 2959 photoinitiator in supercritical carbon dioxide: Ex...
Coimbra, Patrícia; Fernandes, Daniel; Ferreira, Paula; Gil, Maria H.; Sousa, Hermínio C. deCIBA photoinitiator Irgacure® 2959 is a highly efficient radical photoinitiator for UV curing systems. Furthermore, and due to its proven low cellular toxicity, this photoinitiator can also be employed in the photopolymerization of polymers and copolymers intended for biomedical and tissue engineering applications, not only in conventional pharmaceutically accepted liquid solvents, but also in supercritical CO2...
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...
Solubility of Diflunisal in Supercritical Carbon Dioxide
Coimbra, Patrícia; Fernandes, Daniel; Gil, Maria H.; Sousa, Hermínio C. deThe solubility of diflunisal, a nonsteroidal anti-inflammatory drug (NSAID), in supercritical carbon dioxide (scCO2) was measured at (308.2, 318.2, and 328.2) K and in the pressure range from (9.0 up to 25.0) MPa. Results were obtained using a static analytical method. Experimental solubility was found to be between 0.54·10−6 and 8.07·10−6 (in terms of diflunisal mole fraction). Experimental data were satisfact...
Preparation and characterization of flurbiprofen-loaded poly(3-hydroxybutyrate-...
Coimbra, Patrícia A.; Sousa, Hermínio C. de; Gil, Maria H.Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) microspheres containing flurbiprofen were prepared by an oil-in-water emulsion solvent evaporation method, in order to develop a particulate drug delivery system for localized administration. A response surface method (RSM) using a central composite design was employed to evaluate the effect of the poly(vinyl alcohol) (PVA) (%, w/v) concentration in the aqueou...
Fractioned High Pressure Extraction of Anthocyanins from Elderberry ( Sambucus ...
Seabra, Inês J.; Braga, Mara E. M.; Batista, Maria T. P.; Sousa, Hermínio C. deFractionated high pressure extractions from dry and in natura elderberry pomace were performed in order to obtain anthocyanin rich extracts. Experiments were carried out using CO2 supercritical fluid extraction followed by enhanced solvent extraction (ESE) with CO2/EtOH–H2O mixtures (1–100%, v/v), to obtain anthocyanin rich fractions in the second step, at 313 K and ~20 MPa. Higher extract yields, anthocyanin c...
Supercritical solvent impregnation of poly(ɛ-caprolactone)/poly(oxyethylene-b-o...
Natu, Mădălina V.; Gil, M. H.; Sousa, Hermínio C. dePoly(ɛ-caprolactone) blends were successfully impregnated with timolol maleate, an anti-glaucoma drug, using a supercritical solvent impregnation (SSI) technique. Supercritical fluid impregnation efficiency results suggested that the best impregnating conditions were obtained when a cosolvent was used and when specific drug–polymer interactions occurred as a consequence of different chemical structures due to p...
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