Supramolecular assembly of poly(β-cyclodextrin) block copolymer and benzimidazole-poly(ε-caprolactone) based on host-guest recognition for drug delivery.

A well-defined double hydrophilic poly(β-cyclodextrin)-containing diblock copolymer PEG-b-PCD was synthesized by atom transfer radical polymerization (ATRP). Complex micelles with defined core-shell structure were formed based on the host-guest interactions between poly(β-cyclodextrin) block copolymer and benzimidazole modified poly(ε-caprolactone) (BM-PCL). The hydrophobic PCD/BM-PCL resided in the core of micelles, while the hydrophilic poly(ethylene glycol) (PEG) chains acted as the micelles shell. The micelles exhibited regular spheres with diameter of about 255nm. The drug loading efficiency of micelles for doxorubicin (DOX) was high due to the hydrophobic core containing poly(β-CD) and PCL. The in vitro release demonstrated that DOX-loaded polymer micelles exhibited an enhanced sustained manner after an initial burst release. The release of drugs was accelerated as the pH reduced from 7.0 to 2.0 and the temperature increased from 25 to 37°C. These results indicate that the complex micelles have potential applications in controlled drug delivery.