RESUMEN
Abstract In an attempt to increase molecular stability and provide controlled release, vascular endothelial growth factor (VEGF) was encapsulated into polycaprolactone (PCL) nanoparticles. Both VEGF-free and VEGF-loaded PCL nanoparticles were formulated by w/o/w double emulsion of the dichloromethane-water system in the presence of polyvinyl alcohol (PVA) and rat serum albumin. To achieve the optimal formulation concerning particle size and monodispersity, studies were carried out with different formulation parameters, including PVA concentration, homogenization time and rate. Scanning electron microscopy and dynamic light scattering analysis showed respectively that particles had a spherical shape with a smooth surface and particle size varying between 58.68-751.9 nm. All of the formulations were negatively charged according to zeta potential analysis. In vitro release study was performed in pH 7.4 phosphate-buffered saline at 37°C and released VEGF amount was measured by enzyme-linked immunosorbent assay (ELISA) method. At the end of the 35th day, 10% of total encapsulated VEGF was released with a sustained-release profile, which fitted the Korsmeyer-Peppas kinetic model. The bioactivation of the nanoparticles was evaluated using XTT and ELISA methods. As a result, the released VEGF was biologically active and also VEGF loaded PCL nanoparticles enhanced proliferation of the human umbilical vein endothelial cells in cell culture.
Asunto(s)
Factor A de Crecimiento Endotelial Vascular , Nanopartículas/clasificación , Técnicas In Vitro/métodos , Ensayo de Inmunoadsorción Enzimática/métodos , Microscopía Electrónica de Rastreo/métodos , Técnicas de Cultivo de Célula/métodos , Células Endoteliales de la Vena Umbilical HumanaRESUMEN
This study evaluates various techniques for producing mesalamine (5ASA)-loaded particles employing chitosan as a biopolymer: (1) the polyelectrolyte complexation of chitosan with phthalate hypromelose (HP), (2) the chemical crosslinking of chitosan with genipin and (3) the water-in-oil emulsion method associated with chemical crosslinking with genipin. Systems were characterized by dynamic light scattering, zeta potential (ζ), powder X-ray diffraction (PXRD), Fourier transform infrared spectroscopy (FTIR) and a drug release profile. Method (1) was efficiently produced unloaded nanoparticles (491 nm, PdI=0.26 and ζ = 23.2), but the conditions for chitosan and HP cross-linking enhanced the precipitation of 5ASA. Method (2) caused the degradation of the drug. Method 3 produced sub-micron and microparticles, thereby varying the agitation method; 3 h magnetic agitation resulted in 2692 nm, Pdi = 0.6 and ζ = 46, while Ultra-Turrax, 5 min produced submicron particles (537 nm, PdI = 0.6). The percentage yield was approximately 50%, which is very satisfactory considering the impossibility of encapsulating 5ASA using other methods. FTIR showed the covalent interaction of chitosan and genipin. The drug release was rapid in acidic fluid, but in neutral pH a slower release was obtained in the initial stage, followed by rapid release, which may ensure the controlled release of 5ASA in the colon.