Abstract: AimTo perpare and identify irisquinone hydroxypropyl-β-cyclodextrin inclusion complex (irisquinone-HP-β-CD), as well as to study the inclusion mechanism and molecule stoichiometry between irisquinone and hydroxypropyl-β-cyclodextrin. MethodsIrisquinone-HP-β-CD was prepared by freeze-drying technique. The ratio of host and guest was also studied in inclusion process by mol gradient and continuing variational methods. At the same time, the inclusion complex was identified by X-ray diffraction (XRD) and differential scanning calorimetry (DSC). ResultsIt was demonstrated that the solubility of irisquinone was enhanced markedly by inclusion with HP-β-CD when stoichiometry was 2∶1 of host and guest at 25 ℃, 35 ℃ and 45 ℃. ConclusionThe solubility and stability of irisquinone could be increased by preparing the inclusion complex with hydroxypropyl-β-cyclodextrin.