Background: Cyclodextrins (CDs) are commonly used host molecules of inclusion complex. However, due to the lack of a sensitive determination method, the absorption process of CDs remains unclear.

Objective: In this study, an oleuropein (OL) inclusion complex employing hydroxylpropyl-betacyclodextrin (HP-beta-CD) as host molecules was prepared and the formation of inclusion complex was ascertained by FT-IR and DSC. Spectrophotometry was established for the determination of HP-beta-CD, based on the fact that the absorbance of phenolphthalein (PP) decreased in the presence of HP-beta-CD.

Methods: The assay conditions were optimized to augment the method sensitivity. Molecular docking was employed to verify the strong interaction between PP and HP-beta-CD. The permeation process of free HP-beta-CD, HP-beta-CD of OL inclusion complex, free OL, and OL in the inclusion complex, was examined using an in vitro mouse small intestine model.

Results: Though HP-beta-CD possessed a hydrophilic outside shell, it could permeate through the mouse small intestine quickly with a cumulative permeating amount of over 90% in 2 h. Free HPbeta- CD, the host molecule HP-beta-CD, and guest molecule OL of the inclusion complex exhibited consistent permeating profiles across the mouse small intestine.

Conclusion: The approach for the determination of HP-beta-CD was accurate and precise (%RSD=2.98).

背景：环糊精（CDs）是常用的包合物宿主分子。然而，由于缺乏灵敏的测定方法，CDs的吸收过程尚不清楚。

目的：本研究制备了以羟丙基-β-环糊精（HP-β-CD）为主体分子的橄榄苦苷（OL）包合物，并通过FT-IR和DSC确定包合物的形成。基于在HP-β-CD 存在下酚酞(PP) 的吸光度降低这一事实，建立了用于测定HP-β-CD 的分光光度法。

方法：优化分析条件以提高方法灵敏度。分子对接被用来验证 PP 和 HP-β-CD 之间的强相互作用。使用体外小鼠小肠模型检查游离 HP-β-CD、OL 包合物的 HP-β-CD、游离 OL 和包合物中的 OL 的渗透过程。

结果：HP-β-CD虽然具有亲水性外壳，但在小鼠小肠内渗透速度快，2 h累积渗透量达90%以上。包合物的游离 HPbeta-CD、宿主分子 HP-beta-CD 和客体分子 OL 在小鼠小肠中表现出一致的渗透曲线。

结论：HP-β-CD 的测定方法准确且精密（%RSD=2.98）。