Poly(ethylene glycol) crosslinked multi-armed poly(ε-benzyloxycarbonyl-L-lysine)s as super-amphiphiles: Synthesis, self-assembly, and evaluation as efficient delivery systems for poorly water-soluble drugs

Polymeric micelles with high thermodynamic stability and loading capacity are of tremendous significance for their potential applications in drug delivery. In the present study, super-amphiphiles in the form of poly(ethylene glycol)-crosslinked multi-armed polyethylenimine-g-poly(e-benzyloxycarbonyl-L-lysine)s (PEZ-alt-PEG) were designed, synthesized, and optimized as nanocarriers for hydrophobic drugs. In an aqueous solution, the copolymer PEZ-alt-PEG self-assembled into sub-100-nm spherical shell crosslinked micelles with low toxicity in vitro and in vivo. The crosslinked super-amphiphilic structure of PEZ-alt-PEG could not only enhance the thermodynamic stability of polymeric micelles, but it could also significantly improve the loading capacity of hydrophobic drugs, such as curcumin (CUR). CUR-loaded PEZ-alt-PEG micelles could mediate effective drug delivery with sustained and complete CUR release. The use of PEZ-alt-PEG micellar nanocarriers remarkably improved the cellular uptake of CUR and therefore exhibited effective inhibitory activity on the growth of human hepatoma (HepG2) cells. Compared to free CUR, CUR-loaded polymeric micelles significantly accelerated the apoptosis rate of HepG2 cells. Therefore, PEZ-alt-PEG polymeric micelles, with their high thermodynamic stability, high drug-loading capacity, enhanced drug uptake and improved pharmacodynamic effects, could serve as efficient and promising nanocarriers for poorly water-soluble drugs.