Hydrolyzable Polyrotaxanes Consisting of β -Cyclodextrins and Pluronic ® for Drug Delivery

In recent years, polyrotaxanes (PRXs) have been extensively studied as a novel supramolecular assembly that has interlocked structure between a cyclic molecule and a linear polymeric chain. Based on the interlocked structure of PRXs, one can expect excellent properties in terms of supramolecular motion of the cyclic molecules. In pharmaceutical fields, we have studied biodegradable PRXs as a drug carrier, in which many α-cyclodextrins (α-CDs) are threaded onto a poly (ethylene glycol) (PEG) capped with bulky blocking group via peptide linkages1). Drugs were immobilized α-CDs via biodegradable spacer. When the terminals of PRX were enzymatically hydrolyzed, drug-immobilized α-CDs could be released.