Novel drug delivery systems based on the encapsulation of superparamagnetic nanoparticles into lipid nanocomposites

Abstract

Hydrophobic superparamagnetic iron oxide nanoparticles (SPIONs) with an average size of 13 nm prepared by the salt co-precipitation method were included into solid lipid nanoparticles (SLN) and oily-core polymeric nanocapsules (NC) using the emulsification-diffusion technique to form novel lipid-magnetic drug delivery systems. Microscopy showed spherical-shaped composites with a hydrodynamic diameter between 300-400 nm and 450–500 nm for the NC/SPIONs and SLN/SPIONs composites, respectively. The entrapment efficiency (EE) of SPIONs into the NC/SPIONs composite was calculated as 49.0% and 55.7% for batches prepared with 25% and 12.5% (w/w) of SPIONs, respectively. EE for the SLN/SPIONs was calculated as 40.8% and 59.1%, respectively, for batches prepared with 25% and 12.5% SPIONs (w/w). Magnetic measurement revealed that the saturated magnetization of the NC/SPIONs and SLN/SPIONs reached values of 6–12 and 5–9 A m2/Kg, respectively. Also, the remanent magnetization and coercivity was almost zero, suggesting characteristics of superparamagnetism that may have important implications for drug delivery. The in vitro release profiles showed that a model drug could be slowly released from the nanocomposite without interference of SPIONs.