DEFAR - Artigos publicados em periódicos
URI permanente para esta coleçãohttp://www.hml.repositorio.ufop.br/handle/123456789/531
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10 resultados
Resultados da Pesquisa
Item Cloxacillin benzathine-loaded polymeric nanocapsules : physicochemical characterization, cell uptake, and intramammary antimicrobial effect.(2019) Araújo, Raquel Silva; Garcia, Giani Martins; Vilela, José Mário Carneiro; Andrade, Margareth Spangler; Oliveira, Laser Antônio Machado de; Kano, Eunice Kazue; Lange, Carla Christine; Brito, Maria Aparecida Vasconcelos Paiva; Brandão, Humberto de Mello; Mosqueira, Vanessa Carla FurtadoThe present work shows the development and evaluation of the veterinary antibiotic cloxacillin benzathine (CLOXB) loaded into poly-ε-caprolactone (PCL) nanocapsules (NC), as a potential new treatment strategy to manage bovine intramammary infections, such as mastitis. Staphylococcus aureus-induced mastitis is often a recurrent disease due to the persistence of bacteria within infected cells. CLOXB-PCL NC were prepared by interfacial deposition of preformed biodegradable polymer followed by solvent displacement method. The mean diameter of NC varied from 241 to 428 nm and from 326 to 375 nm, when determined by dynamic light scattering and by atomic force microscopy, respectively. The zeta potential of NC was negative and varied from −28 to −51 mV. In vitro release studies from the NC were performed in two media under sink conditions: PBS with 1% polyethylene glycol or milk. A reversed-phase HPLC method was developed to determine the NC entrapment efficiency and kinetics of CLOXB release from the NC. Free CLOXB dissolution occurred very fast in both media, while drug release from the NC was slower and incomplete (below 50%) after 9 h. CLOXB release kinetics from polymeric NC was fitted with the Korsmeyer-Peppas model indicating that CLOXB release is governed by diffusion following Fick's law. The fluorescence confocal microscopy images of macrophage-like J774A.1 cells reveal NC uptake and internalization in vitro. In addition, antimicrobial effect of the intramammary administration of CLOXB-PCL NC in cows with mastitis resulted in no clinical signs of toxicity and allowed complete pathogen elimination after treatment. The in vivo results obtained in this work suggest that CLOXB-PCL NC could be a promising formulation for the treatment of intramammary infections in cattle, considering their physicochemical properties, release profiles and effects on bovine mastitis control.Item Phthalocyanine photosensitizer in polyethylene glycol-block-poly(lactide-co-benzyl glycidyl ether) nanocarriers : probing the contribution of aromatic donor-acceptor interactions in polymeric nanospheres.(2019) Lana, Gwenaelle Elza Nathalie Pound; Garcia, Giani Martins; Trindade, Izabel Cristina; Oliveira, Patricia Capelari de; Pontífice, Thaís Godinho; Vilela, José Mário Carneiro; Andrade, Margareth Spangler; Nottelet, Benjamin; Postacchini, Bruna Bueno; Mosqueira, Vanessa Carla FurtadoFor best photosensitizer activity phthalocyanine dyes used in photodynamic therapy should be molecularly dispersed. Polyethylene glycol-block-polylactide derivatives presenting benzyl side-groups were synthesized to encapsulate a highly lipophilic phthalocyanine dye (AlClPc) and evaluate the effect of π-π interactions on the nanocarrier colloidal stability and dye dispersion. Copolymers with 0, 1, 2 and 6 mol% of benzyl glycidyl ether (BGE) were obtained via polyethylene glycol initiated ring-opening copolymerization of D,L-lactide with BGE. The block copolymers formed stable, monodisperse nanospheres with low in vitro cytotoxicity. AlClPc loading increased the nanosphere size and affected their colloidal stability. The photo-physical properties of the encapsulated dye, studied in batch and after separation by field flow fractionation, demonstrated the superiority of plain PEG-PLA over BGE-containing copolymers in maintaining the dye in its monomeric (non-aggregated) form in aqueous suspension. High dye encapsulation and sustained dye release suggest that these nanocarriers are good candidates for photodynamic therapy.Item Increased body exposure to new anti-trypanosomal through nanoencapsulation.(2017) Branquinho, Renata Tupinambá; Lana, Gwenaelle Elza Nathalie Pound; Milagre, Matheus Marques; Guimarães, Dênia Antunes Saúde; Vilela, José Mário Carneiro; Andrade, Margareth Spangler; Lana, Marta de; Mosqueira, Vanessa Carla FurtadoLychnopholide, a lipophilic sesquiterpene lactone, is efficacious in mice at the acute and chronic phases of Chagas disease. Conventional poly-ε-caprolactone (PCL) and long-circulating poly(D,L-lactide)-block-polyethylene glycol (PLA-PEG) nanocapsules containing lychnopholide were developed and characterized. Lychnopholide presented high association efficiency (>90%) with the nanocapsules. A new, fast and simple HPLC-UV-based bioanalytical method was developed, validated in mouse plasma and applied to lychnopholide quantification in in vitro release kinetics and pharmacokinetics. The nanocapsules had mean hydrodynamic diameters in the range of 100–250 nm, negative zeta potentials (−30 mV to −57 mV), with good physical stability under storage. Atomic force microscopy morphological analysis revealed spherical monodispersed particles and the absence of lychnopholide crystallization or aggregation. Association of lychnopholide to PLA-PEG nanocapsules resulted in a 16-fold increase in body exposure, a 26-fold increase in plasma half-life and a dramatic reduction of the lychnopholide plasma clearance (17-fold) in comparison with free lychnopholide. The improved pharmacokinetic profile of lychnopholide in long-circulating nanocapsules is in agreement with the previously reported improved efficacy observed in Trypanosoma cruzi-infected mice. The present lychnopholide intravenous dosage form showed great potential for further pre-clinical and clinical studies in Chagas disease and cancer therapies.Item Polymeric nanocapsules prevent oxidation of core-loaded molecules : evidence based on the effects of docosahexaenoic acid and neuroprostane on breast cancer cells proliferation.(2015) Roy, Jérôme; Oliveira, Liliam Teixeira; Oger, Camille; Galano, Jean Marie; Poncé, Valerie Bultel; Richard, Sylvain; Guimarães, Andrea Grabe; Vilela, José Mário Carneiro; Andrade, Margareth Spangler; Durand, Thierry; Besson, Pierre; Mosqueira, Vanessa Carla Furtado; Guennec, Jean-Yves LeBackground: Nanocapsules, as a delivery system, are able to target drugs and other biologically sensitive molecules to specific cells or organs. This system has been intensively investigated as a way to protect bioactives drugs from inactivation upon interaction with the body and to ensure the release to the target. However, the mechanism of improved activity of the nanoencapsulated molecules is far from being understood at the cellular and subcellular levels. Epidemiological studies suggest that dietary polyunsaturated fatty acids (PUFA) can reduce the morbidity and mortality from breast cancer. This influence could be modulated by the oxidative status of the diet and it has been suggested that the anti-proliferative properties of docosahexaenoic acid (DHA) are enhanced by pro-oxidant agents. Methods: The effect of encapsulation of PUFA on breast cancer cell proliferation in different oxidative medium was evaluated in vitro. We compared the proliferation of the human breast cancer cell line MDA-MB-231 and of the non-cancer human mammary epithelial cell line MCF 10A in different experimental conditions. Results: DHA possessed anti-proliferative properties that were prevented by alpha-tocopherol (an antioxidant) and enhanced by the pro-oxidant hydrogen peroxide that confirms that DHA has to be oxidized to exert its anti-proliferative properties. We also evaluated the anti-proliferative effects of the 4(RS)-4-F4t-neuroprostane, a bioactive, non-enzymatic oxygenated metabolite of DHA known to play a major role in the prevention of cardiovascular diseases. DHA-loaded nanocapsules was less potent than non-encapsulated DHA while co-encapsulation of DHA with H2O2 maintained the inhibition of proliferation. The nanocapsules slightly improves the anti-proliferative effect in the case of 4(RS)-4-F4t-neuroprostane that is more hydrophilic than DHA. Conclusion: Overall, our findings suggest that the sensitivity of tumor cell lines to DHA involves oxidized metabolites. They also indicate that neuroprostane is a metabolite participating in the growth reducing effect of DHA, but it is not the sole. These results also suggest that NC seek to enhance the stability against degradation, enhance cellular availability, and control the release of bioactive fatty acids following their lipophilicities.Item Improved nonclinical pharmacokinetics and biodistribution of a new PPAR pan-agonist and COX inhibitor in nanocapsule formulation.(2015) Garcia, Giani Martins; Oliveira, Liliam Teixeira; Pitta, Ivan da Rocha; Lima, Maria do Carmo Alves de; Vilela, José Mário Carneiro; Andrade, Margareth Spangler; Parra Abdalla, Dulcinéia Saes; Mosqueira, Vanessa Carla FurtadoWereport the in vitro release profile and comparative pharmacokinetics and biodistribution of a newperoxisome proliferator-activated receptor-γ agonist and cyclooxygenase inhibitor (Lyso-7) free or associated to poly(D,Llactic acid) nanocapsules (NC) after intravenous administration in mice. Lyso-7 pertains to the class of insulinsensitizing agents that shows potential beneficial effects in diabetes therapy. Monodispersed Lyso-7 NC with a mean diameter of 273 nm with high encapsulation efficiency (83%) were obtained. Lyso-7 dissolution rate was reduced (2.6-fold) upon loading in NC. The pharmacokinetic parameters were determined using a noncompartmental approach. In comparison with Lyso-7 in solution, the plasma-AUC increased 14-fold, the mean residence time 2.6-fold and the mean half-life (t1/2) 1.5-fold for Lyso-7-NC; the Lyso-7 plasma clearance, distribution volume and elimination rate were reduced 13, 10 and 1.4 fold, respectively, which indicates higher retention of encapsulated Lyso-7 in the blood compartment. Upon association with NC, organ exposure to Lyso-7 was higher in the heart (3.6-fold), lung (2.8-fold), spleen (2.3-fold), kidney (2-fold) and liver (1.8-fold) compared to Lyso-7 in solution. The analysis of whole data clearly indicates that body exposure to Lyso-7 was enhanced and the general toxicity reduced upon nanoencapsulation, allowing further evaluation of Lyso-7 in nonclinical and clinical studiesItem PLA-PEG nanocapsules radiolabeled with 99mTechnetium-HMPAO : release properties and physicochemical characterization by atomic force microscopy and photon correlation spectroscopy.(2008) Pereira, Maira Alves; Mosqueira, Vanessa Carla Furtado; Vilela, José Mário Carneiro; Andrade, Margareth Spangler; Ramaldes, Gilson Andrade; Cardoso, Valbert NascimentoThe present work describes the preparation, characterization and labelling of conventional and surface-modified nanocapsules (NC) with 99mTc-HMPAO. The size, size distribution and homogeneity were determined by photon correlation spectroscopy (PCS) and zeta potential by laser doppler anemometry. The morphology and the structural organization were evaluated by atomic force microscopy (AFM). The stability and release profile of the NC were determined in vitro in plasma. The results showed that the use of methylene blue induces significant increase in the encapsulation efficiency of 99mTc-HMPAO, from 24.4 to 49.8% in PLANC and 22.37 to 52.93% in the case of PLA-PEGNC(P < 0.05) by improving the complex stabilization. The average diameter of NC calculated by PCS varied from 216 to 323 nm, while the average diameter determined by AFM varied from 238 to 426 nm. The AFM analysis of diameter/height ratios suggested a greater homogeneity of the surface-modified PLAPEG nanocapsules compared to PLA NC concerning their flattening properties. The in vitro release of the 99mTc-HMPAO in plasma medium was faster for the conventional PLA NC than for the surface-modified NC. For the latter, 60% of the radioactivity remained associated with NC, even after 12h of incubation. The results suggest that the surface-modified 99mTc-HMPAO-PLA PEG NCwas more stable against label leakage in the presence of proteins and could present better performance as radiotracer in vivo.Item Polymeric nanostructures for drug delivery : characterization by atomic force microscopy.(2005) Mosqueira, Vanessa Carla Furtado; Leite, Elaine Amaral; Barros, Cristina Maria de; Vilela, José Mário Carneiro; Andrade, Margareth SpanglerItem Release profiles and morphological characterization by atomic force microscopy and photon correlation spectroscopy of 99mTechnetium-fluconazole nanocapsules.(2008) Assis, Danielle Nogueira de; Mosqueira, Vanessa Carla Furtado; Vilela, José Mário Carneiro; Andrade, Margareth Spangler; Cardoso, Valbert NascimentoSeveral classes of antifungal have been employed in candidiasis treatment, but patients with advanced immunodeficiency can present unsatisfactory results after therapy. In these cases, high doses of drugs or the use of multiple agents are sometimes used, and hence increasing the risk of serious side effects. Considering theses difficulties, the encapsulation of antifungal agents in nanoparticulate carriers has been used with the objective of modifying the pharmacokinetic of drugs resulting in more efficient treatments with less side effects. The purpose of this work was the preparation, characterization and the investigation of the release profiles of radiolabeled fluconazole nanocapsules. The size, homogeneity and zeta potential of NC preparations were determined with a Zetasizer 3000HS. The morphology and the structural organization were evaluated by atomic force microscopy (AFM). The release study in vitro of NC was evaluated in physiologic solution with or without 70% mouse plasma. The labeling yield of fluconazole with 99mTc was 94% and the radiolabeled drug was stable within 24 h period. The encapsulation percentage of 99mTc-fluconazole in PLA-POLOX NC and PLA-PEG NC was approximately of 30%. The average diameter calculated by photon correlation spectroscopy (PCS) varied from 236 to 356 nm, while the average diameter determined by AFM varied from 238 to 411 nm. The diameter/height relation decreased significantly when 25% glutaraldehyde was used for NC fixation on mica. The zeta potential varied from −55 to −69 nm and surface-modified NC showed lower absolute values than conventional NC. The in vitro release of 99mTc-fluconazole in plasma medium of the conventional and surface-modified NC was greater than in saline. The drug release in plasma medium from conventional NC was faster than for surface-modified NC. The results obtained in this work suggest that the nanocapsules containing fluconazole could be used to identify infectious foci, due to the properties, such as size, zeta potential and controlled release of 99mTc-fluconazole. The surface-modified nanocapsules could constitute a long-circulating intravenous formulation of fluconazole for treating sepsis caused by disseminated form of candidiasis. However, in vivo studies should be considered and are under investigation.Item Chloroaluminium phthalocyanine polymeric nanoparticles as photosensitisers : photophysical and physicochemical characterisation, release and phototoxicity in vitro.(2013) Paula, Carina Silva de; Tedesco, Antônio Cláudio; Lucas Primo, Fernando; Vilela, José Mário Carneiro; Andrade, Margareth Spangler; Mosqueira, Vanessa Carla FurtadoNanoparticles of poly(D,L-lactide-co-glycolide), poly(D,L-lactide) and polyethylene glycol-blockpoly (D,L-lactide) were developed to encapsulate chloroaluminium phthalocyanine (AlClPc), a new hydrophobic photosensitiser used in photodynamic therapy (PDT). The mean nanoparticle size varied from 115 to 274 nm, and the encapsulation efficiency ranged from 57% to 96% due to drug precipitation induced by different types of polymer. All nanoparticle formulations presented negative zeta potential values (–37 mV to –59 mV), explaining their colloidal stability. The characteristic photophysical parameters were analysed: the absorption spectrum profile, fluorescence quantum yield and transient absorbance decay, with similar values for free and nanoparticles of AlClPc. The time-resolved spectroscopy measurements for AlClPc triplet excited state lifetimes indicate that encapsulation in nanocapsules increases triplet lifetime, which is advantageous for PDT efficiency. A sustained release profile over 168 h was obtained using external sink method. An in vitro phototoxic effect higher than 80% was observed in human fibroblasts at low laser light doses (3 J/cm2) with 10 lM of AlClPc. The AlClPc loaded within polymeric nanocapsules presented suitable physical stability, improved photophysical properties, sustained released profile and suitable activity in vitro to be considered a promising formulation for PDT.Item Poly-caprolactone nanocapsules morphological features by atomic force microscopy.(2005) Leite, Elaine Amaral; Vilela, José Mário Carneiro; Mosqueira, Vanessa Carla Furtado; Andrade, Margareth Spangler