Amphoteric calix[8]arene-based complex for pH-triggered drug delivery

Amphoteric calix[8]arene with negatively charged upper rim and positively charged lower rim was synthesized based on water-soluble p-sulfonato-calix[8]arene. The pH-sensitive amphoteric calix[8]arenes exhibit not only a good hydrophobic drug loading capacity but also a pH-triggered drug releasing behavior. The in vitro release studies demonstrated that release of ciprofloxacin from amphoteric calix[8]arene complexes was highly pH-sensitive. More efficient drug release was observed at mildly acidic pH 5.0 and basic pH 8.5 compared to physiological pH. The amphoteric calix[8]arene complexes hold out great promise of being pH-sensitive drug carrier.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Amphoteric calix[8]arenes with negative charged upper rim and positively charged lower rim were prepared. ► The amphoteric calix[8]arenes exhibit a good hydrophobic drug loading capacity. ► Coupled calix[8]arene complexes or multilayers are formed around pH 7.0 via electrostatic attraction. ► The drug release from the calix[8]arene complexes can be triggered by changing pH conditions.