Cationic amphiphilic copolymers: synthesis, characterization, self-assembly and drug-loading capacity

Amphiphilic copolymers with cationic hydrophilic moieties and different ratios of hydrophobic portion to hydrophilic portion were designed and synthesized via the combination of hydrosilylation reactions and quaternization reactions. The structures were characterized through Fourier transform infrared spectroscopy, 1 H NMR, 13 C NMR and gel permeation chromatography. The measurements of critical micelle concentrations, electrical conductivities and zeta potentials indicated that the copolymers could self-assemble into nanoparticles with charges around the surface in aqueous solution. The sizes of the micelles were between 67 nm and 104 nm detected by dynamic light scattering. The self-assembled micelles were used as drug carriers to encapsulate a model drug (tocopherol), and their drug-loading content (DLC) and efficiency (DLE) were determined by UV−visible spectra, resulting in considerable drug-loading capacity to a tocopherol maximum up to 17.2% (DLC) and 80.3% (DLE) with a size of 90 nm. The blank micelles and drug-loaded micelles displayed a spherical shape detected by transmission electron microscopy, which demonstrated not only the self-assembly behaviors but also the drug-loading performances of the cationic amphiphilic copolymers. All the results demonstrated that the cationic amphiphilic copolymers could be used as potential electric-responsive drug carriers. © 2017 Society of Chemical Industry