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 β-cyclodextrin NS, by microwave-assisted fusion, for the encapsulation of PIP. Different formulations of NS were synthesized by varying the molar ratio of β-cyclodextrin:diphenyl carbonate (β-CD:DPC; 1:2, 1:6 and 1:10). NS specimens derived from 1:2, 1:6 and 1:10 β-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 β-cyclodextrin of high crystallinity for the encapsulation of PIP at high loading capacity.