Synthesis and characterization of amphiphilic lipopolymers for micellar drug delivery.

The objective of this study was to design lipopolymers for hydrophobic drug delivery. Poly(ethylene glycol)-block-poly(2-methyl-2-carboxyl-propylene carbonate-graft-dodecanol) (PEG-PCD) lipopolymers were synthesized and characterized by (1)H NMR, FT-IR, GPC, and DSC. The critical micelle concentration (CMC) of PEG-PCD micelles was around 10(-8) M and decreased with increasing length of hydrophobic block. PEG-PCD micelles could efficiently load a model drug embelin into its hydrophobic core and significantly improve its solubility. The loading capacity was dependent on the polymer core structure, but the length of hydrophobic core had little effect. PEG-PCD formed both spherical and cylindrical micelles, which were dependent on the copolymer structure and composition. PEG-PCD lipopolymers with various hydrophobic core lengths showed similar drug release profiles, which were slower than that of poly(ethylene glycol)-block-poly(2-methyl-2-benzoxycarbonyl-propylene carbonate) (PEG-PBC) micelles. Embelin loaded PEG-PCD micelles showed significant inhibition of C4-2 prostate cancer cell proliferation, while no obvious cellular toxicity was observed for blank micelles.