Physicochemical Characterization of Veronicafolin‐β‐cyclodextrin and Solubility Enhancement of Veronicafolin‐HP‐β‐cyclodextrin Inclusion Compound

Inclusion complexation between veronicafolin, 3,5,4′‐trihydroxy‐6,7,3′‐trimethoxyflavone, and β‐cyclodextrin (β‐CD) was investigated by using 1 H NMR, IR, X‐ray diffraction, thermo gravimetric analysis (TGA), and elemental analysis in the solid state. The elemental analysis showed that the complex (1:1) of flavonol‐β‐CD·20H 2 O with C 39.58% and H 5.75% has been formed. The phase solubility profile of the favonol by UV‐Vis in solution in the presence of hydroxypfropyl‐β‐cyclodextrin (HP‐β‐CD) was classified as A L ‐type, indicating the formation of 1:1 inclusion complex. And the calibration equation y =24148 x +0.0075 ( r =0.9999) and phase‐solubility diagram y=0.4738x‐2.0×10 ‐7 (r=0.9490) were obtained. Stability constant K s was calculated from the phase solubility diagram (K s =4.5×10 6 ). Solubility of the veronicafolin was enhanced in the presence of HP‐β‐CD.