Layer-by-layer polyelectrolyte complex coated poly(methacrylic acid) nanogels as a drug delivery system for controlled release: structural effects

Abstract

Core–shell microspheres have attracted intense interest as drug delivery system (DDS) because of their integrated advantages of the core and shell materials. Here the structural effects, such as the crosslinking degree of the cores and the thickness of the polyelectrolyte complex shells, on the dipyridamole (DIP) loading and release performance were investigated in detail for the first time with the core–shell poly(methacrylic acid)@(chitosan/alginate)_n microsphere as a drug carrier model, fabricated by encapsulating poly(methacrylic acid) (PMAA) nanogels in the layer-by-layer (LbL) engineered chitosan/alginate (CS/AL) multilayer shells. The core–shell microspheres with two-bilayer chitosan/alginate shells (PMAA@(CS/AL)₂) were selected for the in vitro controlled release of the water-insoluble anticancer drug (doxorubicin (DOX)) in simulated body fluids (SBF). After the encapsulation, the DOX-loading capacity increased from 32.18% to 40.12% and the effect of the media pH values on the cumulative release from the PMAA@(CS/AL)₂ was more remarkable than the core material, indicating the encapsulation with the polyelectrolyte multilayer shells was favorable for the drug loading and pH-responsive controlled release. Furthermore, the polyelectrolyte multilayer shells also improved the cytocompatibility of the drug carriers. This understanding will lead to better design of smart core–shell DDS for controlled release.