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1.
Food Chem ; 441: 138338, 2024 May 30.
Artigo em Inglês | MEDLINE | ID: mdl-38194794

RESUMO

This study focuses on the characterisation and incorporation of Moringa oleifera leaf powder (MOP) from Luanda (Angola) and its extract (MOE) in fortified chocolate mousse. Dark green (DG) leaves presented superior nutritional values compared to other leaves. DG contained a higher concentration of mineral salts (10 ± 1 mg/100 g of dry leaves), phenolic compounds (267 ± 4 mg GAE/g), vitamins (1.9 ± 0.2 mg/g of dry extract) and strong antioxidant capacity (IC50, 115 ± 8 µg/mL). Therefore, DG leaves were used to fortify the chocolate mousse. The leaves were prepared in three samples: control, 2 % MOP (w/w) and 2 % MOE (v/v). Textural and rheological analysis of chocolate mousse samples revealed a pseudoplastic profile for all samples, with decreased texture attributes and viscosity due to the incorporation. The sensory evaluation demonstrated that MOP and MOE samples presented 93 % and 88 % resemblance to the original product regarding general acceptance, respectively.


Assuntos
Chocolate , Moringa oleifera , Extratos Vegetais , Pós , Folhas de Planta , Vitaminas
2.
Int J Pharm ; 646: 123451, 2023 Nov 05.
Artigo em Inglês | MEDLINE | ID: mdl-37774759

RESUMO

Biopolymers present ideal properties to be used in wound dressing solutions. By mixing two oppositely charged macromolecules it is possible to form polyelectrolyte complex (PEC) based cryogels using lyophilization. Their application in the biomedical field is limited due to their sterilization requirements, as conventional methods compromise their physicochemical properties. ScCO2 appears as an alternative method for decontamination. This work assessed several cryogel PEC formulations, chitosan-pectin, gelatine-xanthan gum and alginate-gelatine. PEC formation was confirmed by FTIR and rheological analysis. While steam sterilization compromised cryogels' chemical and morphological properties, decontamination with scCO2 proved to be a promising method for decontamination of PEC-cryogels, because, similarly to what is observed with hydrogen peroxide, it does not compromise their physicochemical properties.

3.
Front Plant Sci ; 14: 1191923, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37342130

RESUMO

The root-knot nematode (RKN) Meloidogyne luci presents a threat to the production of several important crops. This nematode species was added to the European Plant Protection Organization Alert list in 2017. The scarce availability of efficient nematicides to control RKN and the phasing out of nematicides from the market have intensified the search for alternatives, such as phytochemicals with bionematicidal properties. The nematicidal activity of 1,4-naphthoquinone (1,4-NTQ) against M. luci has been demonstrated; however, knowledge of the potential mode(s) of action of this compound is still scarce. In this study, the transcriptome profile of M. luci second-stage juveniles (J2), the infective stage, in response to 1,4-NTQ exposure was determined by RNA-seq to identify genes and pathways that might be involved in 1,4-NTQ's mode(s) of action. Control treatments, consisting of nematodes exposed to Tween® 80 (1,4-NTQ solvent) and to water, were included in the analysis. A large set of differentially expressed genes (DEGs) was found among the three tested conditions, and a high number of downregulated genes were found between 1,4-NTQ treatment and water control, reflecting the inhibitory effect of this compound on M. luci, with a great impact on processes related to translation (ribosome pathway). Several other nematode gene networks and metabolic pathways affected by 1,4-NTQ were also identified, clarifying the possible mode of action of this promising bionematicide.

4.
Pharmaceutics ; 15(4)2023 Mar 28.
Artigo em Inglês | MEDLINE | ID: mdl-37111567

RESUMO

The efficiency of photodynamic therapy is often limited by the scarcity of oxygen at the target site. To address this problem, this work proposes the development of a new nanosystem for antimicrobial photodynamic therapy applications (aPDT) where the natural-origin photosensitizer curcumin (CUR) is immersed in an oxygen-rich environment. Inspired by the perfluorocarbon-based photosensitizer/O2 nanocarriers reported in the literature, we developed a new type of silica nanocapsule containing curcumin dissolved in three hydrophobic ionic liquids (ILs) with high oxygen dissolving capacities. The nanocapsules (CUR-IL@ncSi), prepared by an original oil-in-water microemulsion/sol-gel method, had a high IL content and exhibited clear capacities to dissolve and release significant amounts of oxygen, as demonstrated by deoxygenation/oxygenation studies. The ability of CUR-IL solutions and of CUR-IL@ncSi to generate singlet oxygen (1O2) upon irradiation was confirmed by the detection of 1O2 phosphorescence at 1275 nm. Furthermore, the enhanced capacities of oxygenated CUR-IL@ncSi suspensions to generate 1O2 upon irradiation with blue light were confirmed by an indirect spectrophotometric method. Finally, preliminary microbiological tests using CUR-IL@ncSi incorporated into gelatin films showed the occurrence of antimicrobial effects due to photodynamic inactivation, with their relative efficiencies depending on the specific IL in which curcumin was dissolved. Considering these results, CUR-IL@ncSi has the potential to be used in the future to develop biomedical products with enhanced oxygenation and aPDT capacities.

5.
Front Plant Sci ; 13: 867803, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35656011

RESUMO

The scarce availability of efficient and eco-friendly nematicides to control root-knot nematodes (RKN), Meloidogyne spp., has encouraged research toward the development of bionematicides. Naphthoquinones, juglone (JUG) and 1,4-naphthoquinone (1,4-NTQ), are being explored as alternatives to synthetic nematicides to control RKN. This study expands the knowledge on the effects of these natural compounds toward M. luci life cycle (mortality, hatching, penetration, reproduction). M. luci second-stage juveniles (J2)/eggs were exposed to each compound (250, 150, 100, 50, and 20 ppm) to monitor nematode mortality and hatching during 72 h and 15 days, respectively. Tomato seedlings were then inoculated with 200 J2, which had been exposed to JUG/1,4-NTQ for 3 days. The number of nematodes inside the roots was determined at 3 days after inoculation, and the final population density was assessed at 45 days after inoculation. Moreover, the potential mode of action of JUG/1,4-NTQ was investigated for the first time on RKN, through the assessment of reactive oxygen species (ROS) generation, acetylcholinesterase (AChE) in vitro inhibitory activity and expression analysis of ache and glutathione-S-transferase (gst) genes. 1,4-NTQ was the most active compound, causing ≥50% J2 mortality at 250 ppm, within 24 h. At 20 and 50 ppm, hatching was reduced by ≈50% for both compounds. JUG showed a greater effect on M. luci penetration and reproduction, decreasing infection by ≈80% (50 ppm) on tomato plants. However, 1,4-NTQ-induced generation of ROS and nematode vacuolization was observed. Our study confirms that JUG/1,4-NTQ are promising nematicidal compounds, and new knowledge on their physiological impacts on Meloidogyne was provided to open new avenues for the development of innovative sustainable nematicides.

6.
J Control Release ; 343: 469-481, 2022 03.
Artigo em Inglês | MEDLINE | ID: mdl-35131370

RESUMO

Retinal ganglion cell (RGC) loss underlies several conditions which give rise to significant visual compromise, including glaucoma and ischaemic optic neuropathies. Neuroprotection of RGCs is a clinical well-defined unmet need in these diseases, and adenosine A3 receptor (A3R) activation emerges as a therapeutic pharmacological approach to protect RGCs. A porous biodegradable intraocular implant loaded with 2-Cl-IB-MECA (selective A3R agonist) was used as a strategy to protect RGCs. Drug-loaded PCL implants released 2-Cl-IB-MECA for an extended period and the released 2-Cl-IB-MECA limited glutamate-evoked calcium (Ca2+) rise in RGCs. Retinal thinning due to transient ischemia was not prevented by 2-Cl-IB-MECA-PCL implant. However, 2-Cl-IB-MECA-PCL implants decreased retinal cell death, promoted the survival of RGCs, preserved optic nerve structure and anterograde axonal transport. We further demonstrated that 2-Cl-IB-MECA-loaded PCL implants were able to enhance RGC function that was compromised by transient ischemia. Taking into consideration the beneficial effects afforded by 2-Cl-IB-MECA released from the PCL implant, this can be envisaged a good therapeutic strategy to protect RGCs.


Assuntos
Agonistas do Receptor A3 de Adenosina , Células Ganglionares da Retina , Agonistas do Receptor A3 de Adenosina/farmacologia , Humanos , Isquemia/tratamento farmacológico , Receptor A3 de Adenosina/metabolismo , Retina/metabolismo
7.
Antioxidants (Basel) ; 10(9)2021 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-34573101

RESUMO

Bravo de Esmolfe (BE) is a traditional Portuguese apple highly appreciated by consumers due to its peculiar flavor and aroma. This apple contains higher concentration of phenolic compounds than other cultivars and is thus considered a rich source of antioxidants. Its sensorial and functional properties have attracted farmers' associations to increase BE production. However, a large quantity of apples is wasted due to storage/transportation procedures that impact BE's quality attributes. In this work, we applied high-pressure extraction methodologies to generate antioxidant-rich fractions from BE residues aiming at adding high value to these agro-food by-products. We performed a first extraction step using supercritical CO2, followed by a second extraction step where different CO2 + ethanol mixtures (10-100% v/v) were tested. All experiments were carried out at 25 MPa and 50 °C. Extracts were characterized in terms of global yield, phenolic content and antioxidant activity using chemical (ORAC, HOSC, HORAC) and cell-based assays (CAA). We demonstrated that, although the pressurized 100% ethanol condition promoted the highest recovery of phenolic compounds (509 ± 8 mg GAE/100 g BE residues), the extract obtained with 40% ethanol presented the highest CAA (1.50 ± 0.24 µmol QE/g dw) and ORAC (285 ± 16 µmol TEAC/g dw), as well as HOSC and HORAC values, which correlated with its content of epicatechin and procyanidin B2. Noteworthy, this fraction inhibited free radical production in human neurospheroids derived from NT2 cells, a robust 3D cell model for neuroprotective testing.

8.
Environ Sci Pollut Res Int ; 28(23): 29521-29534, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-33559081

RESUMO

The olive mill wastewaters obtained from two different processes, press extraction olive mill wastewater (POMW) from Portugal and two-phase system olive mill wastewater (2POMW) from Spain, were treated to recover phenolic compounds and water sequentially, by the integration of liquid-liquid extraction with Fenton's processes. From the recovered fractions, squalene, oleic acid, tyrosol, syringic acid, and p-coumaric acid were identified, and oleic acid appears in a higher concentration for 2POMW wastewater for all used solvents compared to POMW samples. Recovered fractions presented higher antioxidant activity, but remained antioxidants were found in the residual water. The wastewaters coming from a two-phase extraction method (2POMW) present higher phytotoxicity according to germination index, but the application of Fenton's process was able to improve the water quality to be re-used since an increase on the water biodegradability (BOD5/COD) and toxicity reduction were achieved.


Assuntos
Olea , Águas Residuárias , Peróxido de Hidrogênio , Resíduos Industriais/análise , Ferro , Extração Líquido-Líquido , Oxirredução , Portugal , Espanha , Eliminação de Resíduos Líquidos , Águas Residuárias/análise , Água
9.
Drug Deliv Transl Res ; 10(6): 1537-1551, 2020 12.
Artigo em Inglês | MEDLINE | ID: mdl-32557352

RESUMO

This study investigates the immersion impregnation process of the copaiba oleoresin and leaf extract into SpongostanTM gelatin dressings to be used in wound healing treatment. Copaiba oleoresin and leaf extract were characterized by spectroscopic analyses in order to confirm the identity of bioactive compounds and their compatibility with dressing material. Their antibacterial properties were evaluated and oleoresin activity against Escherichia coli and Staphylococcus aureus bacteria was confirmed while the leaf extract showed activity against S. aureus. Solubility assays in organic solvents revealed that copaiba oleoresin is miscible into dichloromethane, while leaf extract showed a 20 g/ml solubility coefficient at 35 °C in the same solvent. These miscibility and solubility conditions were selected for the impregnation process. Using the organic solvent immersion method, 11 mg of copaiba oleoresin and 19 mg of leaf extract were impregnated into 1 cm3 of 3D matrix. The main bioactives from copaiba products, such as ß-caryophyllene and lupeol, were tracked in the gelatin dressing. DSC and TGA assays showed no thermal changes in the samples after impregnation. Furthermore, the spatial organization of foam structure of the dressings was preserved after superficial distribution of oleoresin, as well as amorphous-like particulate deposition of leaf extract. The main compound of copaiba oleoresin, ß-caryophyllene, which exhibits well-known anti-inflammatory activities, and the main compound of copaiba leaf extract, lupeol, also an anti-inflammatory agent, were successfully impregnated using organic solvent in wound dressings and are promising for further application on tissue wound healing. Graphical Abstract.


Assuntos
Bandagens , Fabaceae , Compostos Fitoquímicos/farmacologia , Extratos Vegetais/farmacologia , Antibacterianos/farmacologia , Anti-Inflamatórios/farmacologia , Fabaceae/química , Gelatina , Folhas de Planta/química , Staphylococcus aureus/efeitos dos fármacos
10.
J Control Release ; 316: 331-348, 2019 12 28.
Artigo em Inglês | MEDLINE | ID: mdl-31715277

RESUMO

This work reports the development of porous poly (ε-caprolactone) (PCL)-based intraocular implants, prepared by green supercritical carbon dioxide (scCO2) foaming/mixing method (SFM), to produce implants that degrade faster than typical slow-degrading PCL-based implants. The higher porosities and surface areas of these implants led to faster degradation rates at in vitro accelerated alkaline conditions than low porosity/surface area implants prepared by hot melting processing. These porous implants also presented distinct (faster) release rates of a test-drug (dexamethasone). Additionally, these porous devices did not cause cell death and did not reduce the number of neurons, indicating that are not toxic to retinal cells. We further explored the impact of PCL-based implant to the retina by in vivo evaluation and histological analysis. Implants were surgically inserted in the vitreous of Wistar rats, and their presence did not change the function, structure and anatomy of the retina. These devices demonstrated a good intraocular tolerance, further confirming their viability for prolonged drug delivery applications. Further comprehensive studies based on this promising preliminary assessment and proof-of-concept could enable its future translation to clinical protective strategies for retinal diseases.


Assuntos
Anti-Inflamatórios/administração & dosagem , Dexametasona/administração & dosagem , Sistemas de Liberação de Medicamentos , Poliésteres/química , Administração Oftálmica , Animais , Anti-Inflamatórios/toxicidade , Preparações de Ação Retardada , Dexametasona/toxicidade , Portadores de Fármacos/química , Implantes de Medicamento , Liberação Controlada de Fármacos , Porosidade , Ratos , Ratos Wistar , Retina/metabolismo
11.
Mater Sci Eng C Mater Biol Appl ; 93: 595-605, 2018 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-30274091

RESUMO

This study aimed to evaluate the effect of poly(dimethylsiloxane) on the mechanical properties of chitosan-alginate (CA) polyelectrolyte complexes (PECs) with potential application as wound dressing biomaterials. For that purpose, different amounts of poly(dimethylsiloxane) were incorporated during the formulation of the PECs. Results showed that the highest tensile strength was observed when using 0.1 g of poly(dimethylsiloxane) per gram of PEC (CAS10). This formulation was also non-hemolytic, capable of inducing thrombus formation to potentially reduce bleeding, and additionally presented high stability when exposed to physiological fluids and/or conditions simulating patient bathing. To improve its wound healing capacity, this formulation was loaded with thymol and beta-carotene (anesthetic, anti-inflammatory and antioxidant compounds) by the supercritical carbon dioxide impregnation/deposition (SSI/D) method at 250 bar and 45 °C for 14 h and at two depressurization rates (5 and 10 bar/min). The PECs were also loaded by conventional impregnation in solution for comparison purposes. Higher bioactive loadings, of 1.8 ±â€¯0.2 and 1.3 ±â€¯0.03 µg per milligram of PEC for thymol and beta-carotene, respectively, were observed when using SSI/D and a higher depressurization rate (10 bar/min). These values do not correspond to the maximum loaded amount of each bioactive, which were strongly retained in the PEC structure due to favorable bioactive-polymer interactions, originating matrices that should present a more sustained release during in vivo applications.


Assuntos
Bandagens , Dimetilpolisiloxanos/química , Teste de Materiais , Timol/química , beta Caroteno/química , Animais , Coelhos
12.
Adv Drug Deliv Rev ; 131: 22-78, 2018 06.
Artigo em Inglês | MEDLINE | ID: mdl-30026127

RESUMO

Low drug bioavailability, which is mostly a result of poor aqueous drug solubilities and of inadequate drug dissolution rates, is one of the most significant challenges that pharmaceutical companies are currently facing, since this may limit the therapeutic efficacy of marketed drugs, or even result in the discard of potential highly effective drug candidates during developmental stages. Two of the main approaches that have been implemented in recent years to overcome poor drug solubility/dissolution issues have frequently involved drug particle size reduction (i.e., micronization/nanonization) and/or the modification of some of the physicochemical and structural properties of poorly water soluble drugs. A large number of particle engineering methodologies have been developed, tested, and applied in the synthesis and control of particle size/particle-size distributions, crystallinities, and polymorphic purities of drug micro- and nano-particles/crystals. In recent years pharmaceutical processing using supercritical fluids (SCF), in general, and supercritical carbon dioxide (scCO2), in particular, have attracted a great attention from the pharmaceutical industry. This is mostly due to the several well-known advantageous technical features of these processes, as well as to other increasingly important subjects for the pharmaceutical industry, namely their "green", sustainable, safe and "environmentally-friendly" intrinsic characteristics. In this work, it is presented a comprehensive state-of-the-art review on scCO2-based processes focused on the formation and on the control of the physicochemical, structural and morphological properties of amorphous/crystalline pure drug nanoparticles. It is presented and discussed the most relevant scCO2, scCO2-based fluids and drug physicochemical properties that are pertinent for the development of successful pharmaceutical products, namely those that are critical in the selection of an adequate scCO2-based method to produce pure drug nanoparticles/nanocrystals. scCO2-based nanoparticle formation methodologies are classified in three main families, and in terms of the most important role played by scCO2 in particle formation processes: as a solvent; as an antisolvent or a co-antisolvent; and as a "high mobility" additive (a solute, a co-solute, or a co-solvent). Specific particle formation methods belonging to each one of these families are presented, discussed and compared. Some selected amorphous/crystalline drug nanoparticles that were prepared by these methods are compiled and presented, namely those studied in the last 10-15 years. A special emphasis is given to the formation of drug cocrystals. It is also discussed the fundamental knowledge and the main mechanisms in which the scCO2-based particle formation methods rely on, as well as the current status and urgent needs in terms of reliable experimental data and of robust modeling approaches. Other addressed and discussed topics include the currently available and the most adequate physicochemical, morphological and biological characterization methods required for pure drug nanoparticles/nanocrystals, some of the current nanometrology and regulatory issues associated to the use of these methods, as well as some scale-up, post-processing and pharmaceutical regulatory subjects related to the industrial implementation of these scCO2-based processes. Finally, it is also discussed the current status of these techniques, as well as their future major perspectives and opportunities for industrial implementation in the upcoming years.


Assuntos
Dióxido de Carbono/química , Cromatografia com Fluido Supercrítico , Nanopartículas/química , Preparações Farmacêuticas/síntese química , Humanos , Preparações Farmacêuticas/química
13.
Int J Pharm ; 479(1): 11-22, 2015 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-25541145

RESUMO

Homogeneous poly(ε-caprolactone) (PCL) and poloxamines (PLXs) porous blends were prepared using a supercritical carbon dioxide-assisted foaming/mixing (SFM) approach aiming to obtain cytocompatible implantable materials presenting tunable morphologies, bioerosion rates, bioactive molecules release and osteogenic features. Pure PCL, pure PLXs (T908 and T1107 varieties) and three distinct PCL:PLX 75:25, 50:50, 25:75% w/w blends, with and without the osteogenic and angiogenic bioactive molecule simvastatin were processed at constant pressure of 20 MPa and temperature of 40 °C or 43 °C, for T1107 and T908, respectively. Obtained porous blends were characterized applying a wide range of techniques and in vitro methods. Calorimetric analysis showed that hydrophilic T908 and T1107 PLXs are miscible with PCL for all tested compositions. Prepared PCL:PLX porous blends rapidly lost mass when immersed into phosphate buffer pH 7.4 due to PLXs dissolution and then went through slow and almost constant erosion rates for the subsequent weeks due to PCL slow hydrolytic degradation, which explains the rapid initial release of simvastatin and its subsequent sustained release for longer periods of time. PCL and PCL:PLX 75:25% w/w porous blends, containing or not simvastatin, showed a high cytocompatibility with SAOS-2 cells. In addition, prepared biomaterials promoted mesenchymal stem cells proliferation and their differentiation into osteoblasts. Overall, obtained results showed novel possibilities of addressing local treatment of small bone defects/fractures using highly porous PCL:PLX homogeneous blends.


Assuntos
Etilenodiaminas/química , Poliésteres/química , Polietilenoglicóis/química , Sinvastatina/química , Diferenciação Celular/efeitos dos fármacos , Linhagem Celular , Proliferação de Células/efeitos dos fármacos , Células Cultivadas , Composição de Medicamentos , Liberação Controlada de Fármacos , Etilenodiaminas/administração & dosagem , Humanos , Células-Tronco Mesenquimais/citologia , Células-Tronco Mesenquimais/efeitos dos fármacos , Poliésteres/administração & dosagem , Polietilenoglicóis/administração & dosagem , Porosidade , Sinvastatina/administração & dosagem
14.
Eur J Pharm Biopharm ; 82(2): 383-91, 2012 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-22846620

RESUMO

Cataracts treatment usually involves the extraction of the opaque crystalline lens and its replacement by an intraocular lens (IOL). A serious complication is the occurrence of endophthalmitis, a post-surgery infection mainly caused by Staphylococcus epidermidis, Staphylococcus aureus, and Pseudomonas aeruginosa. IOLs having the ability to load and to release norfloxacin in a controlled way and at efficient therapeutic levels may help to overcome these issues. In this work, acrylic hydrogels combining 2-hydroxyethyl methacrylate (HEMA) and 2-butoxyethyl methacrylate (BEM) at various ratios were prepared to attain biocompatible networks that can be foldable even in the dry state and thus insertable through minor ocular incision, and that load therapeutic amounts of norfloxacin. Acrylamide (AAm) and methacrylic acid (MAAc) were also incorporated as functional comonomers in small proportions. Water sorption, contact angle, protein adsorption, and optical properties of the networks were characterized. BEM notably decreased the T(g) of the networks, but also the loading by immersion in aqueous solution (presoaking). Then, a scCO(2)-based impregnation/deposition (SSI) method was implemented to improve the uptake of the drug. Loading capacities were discussed in terms of the comonomers composition and the employed method and operational conditions. The networks prepared with HEMA/BEM 20:80 vol/vol and processed with supercritical fluids combine adequate mechanical properties, biocompatibility and norfloxacin loading/release, and seem to be suitable for developing norfloxacin-eluting IOLs.


Assuntos
Resinas Acrílicas/química , Dióxido de Carbono/química , Lentes Intraoculares/microbiologia , Norfloxacino/química , Água/química , Acrilamida/administração & dosagem , Acrilamida/química , Resinas Acrílicas/administração & dosagem , Hidrogéis/química , Teste de Materiais/métodos , Metacrilatos/administração & dosagem , Metacrilatos/química , Norfloxacino/administração & dosagem , Infecções Relacionadas à Prótese/prevenção & controle , Soluções/química , Infecções Estafilocócicas/prevenção & controle
15.
Acta Biomater ; 8(3): 1366-79, 2012 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-22085860

RESUMO

This work reports and discusses the influence of four phosphonium-based ionic liquids (PhILs), namely trihexyl(tetradecyl) phosphonium dicyanamide, [P(6,6,6,14)][dca]; trihexyl(tetradecyl) phosphonium bis(trifluoromethylsulfonyl)imide, [P(6,6,6,14)][Tf(2)N]; tetrabutyl phosphonium bromide, [P(4,4,4,4)][Br]; and tetrabutyl phosphonium chloride, [P(4,4,4,4)][Cl], on some of the chemical, physical and biological properties of a biomedical-grade suspension of poly(vinyl chloride) (PVC). The main goal of this work was to evaluate the capacity of these PhILs to modify some of the properties of neat PVC, in particular those that may allow their use as potential alternatives to traditional phthalate-based plasticizers in PVC biomedical applications. PVC films having different PhIL compositions (0, 5, 10 and 20 wt.%) were prepared (by solvent film casting) and characterised by Fourier transform infrared, thermogravimetric analysis, differential scanning calorimetry, dynamical mechanical thermal analysis, scanning electron microscopy/energy-dispersive X-ray/electron probe microanalysis, X-ray diffraction, transmittance, permeability towards oxygen and carbon dioxide, thermal degradation, contact angle measurement, water and vapour uptake, leachability and biocompatibility (haemolytic potential, thrombogenicity and cytotoxicity). A conventional organic plasticizer (di-isononyl phthalate) was used for comparison purposes. The results obtained showed that it was possible to change the neat PVC hydrophobicity, and consequently its water uptake capacity and plasticizer leachability, just by changing the PhIL employed and its composition. It was also possible to significantly change the thermal and mechanical properties of PVC films by choosing appropriate PhIL cation/anion combinations. However, a specific PhIL may not always be capable of simultaneously keeping and/or improving both physical properties. In addition, ionic halide salts were found to promote PVC dehydrochlorination. Finally, none of the prepared materials presented toxicity against Caco-2 cells, though pure [P(6,6,6,14)][dca] decreased HepG2 cells viability. Moreover, PVC films with [P(6,6,6,14)][dca] and [P(4,4,4,4)][Cl] were found to be haemolytic and thus these PhILs must be avoided as PVC modifiers if biomedical applications are envisaged. In conclusion, from all the PhILs tested, [P(6,6,6,14)][Tf(2)N] showed the most promising results regarding blood compatibility, leaching and permeability to gases of PVC films. The results presented are a strong indicator that adequate PhILs may be successfully employed as PVC multi-functional plasticizers for a wide range of potential applications, including those in the biomedical field.


Assuntos
Teste de Materiais , Membranas Artificiais , Compostos Organofosforados/química , Cloreto de Polivinila/química , Células CACO-2 , Sobrevivência Celular , Células Hep G2 , Humanos
16.
Int J Pharm ; 420(2): 231-43, 2011 Nov 28.
Artigo em Inglês | MEDLINE | ID: mdl-21906665

RESUMO

In this work we employed a supercritical solvent impregnation (SSI) process using a scCO(2)+EtOH (5% molar) solvent mixture to impregnate acetazolamide (ACZ) into commercially available silicone-based soft contact lenses (Balafilcon A, Pure Vision, Bausch & Lomb). Contact lenses (SCLs) drug-loading was studied at 40°C and 50°C, and from 15 MPa up to 20 MPa, and using low depressurization rates in order to avoid any harm to SCLs. The effect of impregnation processing time on the loaded ACZ amounts was also studied (1, 2 and 3h). In vitro drug release kinetics studies were performed and the released ACZ was quantified spectrophotometrically. Several analytical techniques were employed in order to characterize the processed and non-processed SCLs in terms of some of their important functional properties. Obtained results demonstrated that ACZ-loaded therapeutic Balafilcon A SCLs can be successfully prepared using the employed SSI process. Furthermore, it was possible to control ACZ loaded amounts and, consequently, to adjust the final ACZ release levels into the desired therapeutic limits, just by changing the employed operational conditions (P, T, processing time and depressurization rate) and without change some of their most important thermomechanical, surface/wettability and optical properties. Obtained soft contact lenses can be potentially employed as combined biomedical devices for simultaneous therapeutic and correction of refractive deficiencies purposes.


Assuntos
Acetazolamida/química , Inibidores da Anidrase Carbônica/química , Lentes de Contato Hidrofílicas , Composição de Medicamentos/métodos , Sistemas de Liberação de Medicamentos , Acetazolamida/administração & dosagem , Administração Oftálmica , Varredura Diferencial de Calorimetria , Dióxido de Carbono/química , Inibidores da Anidrase Carbônica/administração & dosagem , Estabilidade de Medicamentos , Etanol/química , Cinética , Microscopia Eletrônica de Varredura , Fenômenos Ópticos , Pressão , Cloreto de Sódio/química , Solventes/química , Espectroscopia de Infravermelho com Transformada de Fourier , Temperatura , Termogravimetria , Difração de Raios X
17.
Acta Biomater ; 7(3): 1019-30, 2011 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-20934541

RESUMO

The aim of this work was to develop an innovative supercritical fluid (SCF)-assisted molecular imprinting method to endow commercial soft contact lenses (SCLs) with the ability to load specific drugs and to control their release. This approach seeks to overcome the limitation of the common loading of preformed SCLs by immersion in concentrated drug solutions (only valid for highly water soluble drugs) and of the molecular imprinting methods that require choice of the drug before polymerization and thus to create drug-tailored networks. In particular, we focused on improving the flurbiprofen load/release capacity of daily wear Hilafilcon B commercial SCLs by the use of sequential SCF flurbiprofen impregnation and extraction steps. Supercritical carbon dioxide (scCO2) impregnation assays were performed at 12.0 MPa and 40 °C, while scCO2 extractions were performed at 20.0 MPa and 40 °C. Conventional flurbiprofen sorption and drug removal experiments in aqueous solutions were carried out for comparison purposes. SCF-processed SCLs showed a recognition ability and a higher affinity for flurbiprofen in aqueous solution than for the structurally related ibuprofen and dexamethasone, which suggests the creation of molecularly imprinted cavities driven by both physical (swelling/plasticization) and chemical (carbonyl groups in the network with the C-F group in the drug) interactions. Processing with scCO2 did not alter some of the critical functional properties of SCLs (glass transition temperature, transmittance, oxygen permeability, contact angle), enabled the control of drug loaded/released amounts (by the application of several consecutive processing cycles) and permitted the preparation of hydrophobic drug-based therapeutic SCLs in much shorter process times than those using conventional aqueous-based molecular imprinting methods.


Assuntos
Lentes de Contato , Portadores de Fármacos , Anti-Inflamatórios não Esteroides/administração & dosagem , Flurbiprofeno/administração & dosagem , Oxigênio/química , Espectroscopia de Infravermelho com Transformada de Fourier , Água/química
19.
J Agric Food Chem ; 51(22): 6604-11, 2003 Oct 22.
Artigo em Inglês | MEDLINE | ID: mdl-14558784

RESUMO

Turmeric extracts were obtained from two lots of raw material (M and S) using various techniques: hydrodistillation, low pressure solvent extraction, Soxhlet, and supercritical extraction using carbon dioxide and cosolvents. The solvents and cosolvents tested were ethanol, isopropyl alcohol, and their mixture in equal proportions. The composition of the extracts was determined by gas chromatography-flame ionization detection (GC-FID) and UV. The largest yield (27%, weight) was obtained in the Soxhlet extraction (turmeric (S), ethanol = 1:100); the lowest yield was detected in the hydrodistillation process (2.1%). For the supercritical extraction, the best cosolvent was a mixture of ethanol and isopropyl alcohol. Sixty percent of the light fraction of the extracts consisted of ar-turmerone, (Z)-gamma-atlantone, and (E)-gamma-atlantone, except for the Soxhlet extracts (1:100, ethanol), for which only ar-turmeronol and (Z)-alpha-atlantone were detected. The maximum amount of curcuminoids (8.43%) was obtained using Soxhlet extraction (ethanol/isopropyl alcohol). The Soxhlet and low pressure extract exhibited the strongest antioxidant activities.


Assuntos
Antioxidantes/análise , Manipulação de Alimentos/métodos , Extratos Vegetais/química , Tolueno/análogos & derivados , Antioxidantes/química , Cromatografia Gasosa , Cromatografia com Fluido Supercrítico , Curcuma/crescimento & desenvolvimento , Curcumina/análise , Cetonas/análise , Sesquiterpenos , Solventes , Tolueno/análise
20.
J Agric Food Chem ; 51(9): 2520-5, 2003 Apr 23.
Artigo em Inglês | MEDLINE | ID: mdl-12696930

RESUMO

In the present study the antioxidant, anticancer, and antimycobacterial activities of extracts from ginger (Zingiber officinale Roscoe), rosemary (Rosmarinus officinalis L.), and turmeric (Curcuma longa L.) were evaluated. The extracts were obtained using supercritical CO(2) with and without ethanol and/or isopropyl alcohol as cosolvent. The extracts' antioxidant power was assessed using the reaction between beta-carotene and linolenic acid, the antimycobacterial activity against M. tuberculosis was measured by the MABA test, and their anticancer action was tested against nine human cancer ancestries: lung, breast, breast resistant, melanoma, colon, prostate, leukemia, and kidney. The rosemary extracts exhibited the strongest antioxidant and the lowest antimycobacterial activities. Turmeric extracts showed the greatest antimycobacterial activity. Ginger and turmeric extracts showed selective anticancer activities.


Assuntos
Curcuma/química , Extratos Vegetais/isolamento & purificação , Extratos Vegetais/farmacologia , Rosmarinus/química , /química , Antibacterianos/isolamento & purificação , Antibacterianos/farmacologia , Anticarcinógenos/isolamento & purificação , Anticarcinógenos/farmacologia , Antioxidantes/isolamento & purificação , Antioxidantes/farmacologia , Dióxido de Carbono , Cromatografia Gasosa-Espectrometria de Massas/métodos , Mycobacterium/efeitos dos fármacos , Mycobacterium/crescimento & desenvolvimento
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