Core – Shell pH-Responsive Poly(Vinylpyrrolidone)-Block-Poly(Ethylene Glycol)-Block-Poly(Methacrylic Acid) Coated Magnetic Nanoparticle as a Carrier for Delivery of Poorly Water-Soluble Lovastatin

Resumo

A new biodegradable magnetic polymeric nano-carrier based on magnetite nanoparticles encapsulated by poly(vinylpyrrolidone(-block-poly(ethylene glycol)-block-poly(methacrylic acid) (PVP-PEG-PMAA) matrix has been developed for targeted and controlled delivery of lovastatin. The carrier was characterized by TEM, SEM, XRD, VSM, TGA, DSC and FT-IR techniques and its carboxylic acid content was determined by acid-base titration. The carrier has a mean particle diameter of 22 nm with a narrow size distribution and is superparamagnetic with a saturation magnetization of 27.3 emu g^-1 at room temperature. The nano-carrier also possesses pH-responsive properties due to the polymeric layer covering the nanoparticle surface, which adopts conformational changes in the polymer and improves its loading and delivery efficiency. The loading efficiency and pH-controlled release properties of the carrier were examined using a hydrophobic model drug lovastatin. Typically, a loading efficiency of about 94% and a sustained release of 12 h were achieved under simulated human body conditions (37°C; pH 1.2, 5.5 and 7.2). The results indicate that the PVP-PEG-PMAA covalently-coated magnetic nanoparticle is a stable carrier with good loading capacity and controlled-release properties.