Study on Inclusion Behavior of Sophocarpine with ss-Cyclodextrin and Its Derivatives

By using sophocarpine ( SOP) as the guest, and ss-cyclodextrin ( ss- CD), hydroxypropyl-ss cyclodextrin ( HP-ss-CD), trimethyl-ss-cyclodextrin ( TM-ss-CD), mono-( 6-ethanediamine-6- deoxy)-ss cyclodextrin (2N-ss-CD) and mono-(6-diethylenetriamine-6- deoxy)-ss-cyclodextrin ( 3N-ss-CD) as the host, five host-guest inclusions were prepared by the saturated solution method. The host-guest inclusion complexes were characterized by one-dimensional and two-dimensional nuclear magnetic resonance ( H-1 NMR, 2D NMR), ultraviolet-visible spectroscopy ( UV-Vis), X- ray powder diffraction ( XRD) and scanning electron microscopy ( SEM). The results showed that the host-guest inclusion ratios of the SOP to the five cyclodextrins were all 1 : 1. After the formation of inclusion complexes, the water solubility and stability of SOP were obviously increased, and the inclusion compounds were more stable under acidic conditions. Nuclear magnetic resonance analysis showed that the D ring of SOP entered its cavity from the narrow side of the CDs, while the C ring of SOP penetrated the cavity of CDs.