Degree of crosslinking in β-cyclodextrin-based nanosponges and their effect on piperine encapsulation

Piperine (PIP) is an alkaloid which is potent as a therapeutic agent. However, its applications are restricted by its poor water solubility. Nanosponges (NS) derived from polymers are versatile carriers for poor water-soluble substances. The aim of this work was to synthesize beta-cyclodextrin NS, by microwave-assisted fusion, for the encapsulation of PIP. Different formulations of NS were synthesized by varying the molar ratio of beta-cyclodextrin:diphenyl carbonate (beta-CD:DPC; 1:2, 1:6 and 1:10). NS specimens derived from 1:2, 1:6 and 1:10 beta-CD:DPC molar ratios exhibited degree of substitution values of 0.345, 0.629 and 0.878, respectively. The crystallinity of NS was enhanced by increasing diphenyl carbonate concentration. A high degree of crosslinking in the NS increased the loading efficiency due to increased surface area available for bioactive inclusion. This study demonstrated the feasibility of synthesizing NS derived from beta-cyclodextrin of high crystallinity for the encapsulation of PIP at high loading capacity.