Resibufogenin (RBG) is a natural medicinal ingredient with promising cardiac protection and antitumor activity. However, poor solubility and severe gastric mucosa irritation restrict its application in the pharmaceutical field. In this study, the inclusion complex of RBG with β-cyclodextrin (β-CD) and 2-hydroxypropyl-β-cyclodextrin (HP-β-CD) was prepared using the co-evaporation method, and the molar ratio of RBG to CD was determined to be approximately 1:2 by continuous variation plot for both CDs. The formation of inclusion complexes between RBG and each CD (RBG/β-CD and RBG/HP-β-CD) was evaluated by phase solubility study, Fourier transform infrared spectroscopy, and thin-layer chromatography. Powder X-ray diffraction and differential scanning calorimetry confirmed drug amorphization and encapsulation in the molecular cage for both CDs. Moreover, the inclusion complexes’ morphologies were observed using scanning electron microscopy. The dissolution rate of the inclusion complexes was markedly improved compared to that of RBG, and the complexes retained their antitumor activity, as shown in the in vitro cytotoxicity assay on a human lung adenocarcinoma cancer (A549) cell line. Moreover, less gastric mucosal irritation was observed for the inclusion complex. Thus, the inclusion complex should be considered a promising strategy for the delivery of poorly water-soluble anticancer agents, such as RBG.

中文翻译：

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瑞布福配基与 β-环糊精或 2-羟丙基-β-环糊精复合形成提高溶解能力和减少胃粘膜刺激

Resibufogenin (RBG) 是一种天然药用成分，具有良好的心脏保护和抗肿瘤活性。但溶解性差和对胃黏膜刺激性严重限制了其在医药领域的应用。本研究采用共蒸发法制备了RBG与β-环糊精（β-CD）和2-羟丙基-β-环糊精（HP-β-CD）的包合物，RBG与CD的摩尔比为通过两张 CD 的连续变化图确定约为 1:2。通过相溶解度研究、傅里叶变换红外光谱和薄层色谱法评估了 RBG 和每个 CD（RBG/β-CD 和 RBG/HP-β-CD）之间包合复合物的形成。粉末 X 射线衍射和差示扫描量热法证实了两种 CD 的分子笼中的药物非晶化和封装。此外，使用扫描电子显微镜观察了包合物的形态。与 RBG 相比，包合复合物的溶出率显着提高，并且复合物保留了其抗肿瘤活性，如对人肺腺癌细胞 (A549) 细胞系的体外细胞毒性试验所示。此外，对于包合物，观察到较少的胃粘膜刺激。因此，包合物应该被认为是一种有前景的用于递送水溶性差的抗癌剂（如 RBG）的策略。如对人肺腺癌细胞 (A549) 细胞系的体外细胞毒性试验所示。此外，对于包合物，观察到较少的胃粘膜刺激。因此，包合物应该被认为是一种有前景的用于递送水溶性差的抗癌剂（如 RBG）的策略。如对人肺腺癌细胞 (A549) 细胞系的体外细胞毒性试验所示。此外，对于包合物，观察到较少的胃粘膜刺激。因此，包合物应该被认为是一种有前景的用于递送水溶性差的抗癌剂（如 RBG）的策略。