A medusa-like β-cyclodextrin with 1-methyl-2-(2′-carboxyethyl) maleic anhydrides, a potential carrier for pH-sensitive drug delivery

We developed a new pH-sensitive drug delivery carrier based on beta-cyclodextrin (beta-CD) and 1-methyl-2-(2'-carboxyethyl) maleic anhydrides (MCM). The primary hydroxyl groups of beta-CD were successfully attached to MCM residues to produce a medusa-like beta-CD-MCM. The MCM residue was conjugated with cephradine (CP) with high efficiency (> 90%). More importantly, beta-CD-MCM-CP responded to the small pH drop from 7.4 to 5.5 and released greater than 80% of the drugs within 0.5 h at pH 5.5. In addition, the inclusion complex between beta-CD-MCM-CP and the adamantane derivative was formed by simple mixing to show the possibility of introducing multi-functionality. Based on these results, beta-CD-MCM can target weakly acidic tissues or organelles, such as tumours, inflammatory tissues, abscesses or endosomes, and be easily modified with various functional moieties, such as ligands for cell binding or penetration, enabling more efficient and specific drug delivery.