Binding behaviour and solubilisation of p-sulfonatocalixarenes to cinchona alkaloids

Abstract

In this study, we investigated the binding behaviours of three water-soluble p-sulfonatocalixarenes with four cinchona alkaloids in aqueous and phosphate buffer solutions (pH 7.2 and 2.0). The complexation stability constants obtained by fluorescence titrations were comparatively discussed from several aspects: host cavity, pH effect and ionic strength. Among three hosts, p-sulfonatocalix[4]arene (SC4A) forms the most stable complexes with cinchona alkaloids, especially in acidic aqueous conditions. Furthermore, SC4A was elected as model drug carrier for cinchona alkaloids, where solubilisation by the complexation of SC4A and mimic release from the calixarene cavity in the presence of negatively charged micelles were initially studied.

Keywords::

• calixarene
• cinchona alkaloids
• host–guest complexation
• solubilisation

Additional information

Funding

This work was supported by 973 Program [grant number 2011CB932502] and NSFC [grant number 91227107], [grant number 21172119], [grant number 21322207], which are gratefully acknowledged.