Tanshinone IIA@β-cyclodextrin encapsulated with Eucommia ulmoides rubber/acetylated starch film as novel oral delivery system for therapy of orthotopic colon cancer.

Oral drug delivery plays a key role in the treatment of colon cancer. In this study, as a novel oral delivery system, drug tanshinone IIA (Tan IIA) was firstly loaded into β-cyclodextrin (β-CD) to prepare Tan IIA@β-CD, which was subsequently encapsulated by Eucommia ulmoides rubber (EUR)/acetylated starch (AS) film to endow it colon-targeted drug release function. The constructed EUR/AS/Tan IIA@β-CD was characterized using zeta potential, FT-IR, UV-vis, XRD, TG, SEM, and TEM. Moreover, in vitro release experiments revealed that the composite at optimal AS content (95 %) showed Tan IIA cumulative release rate of only 10 % in SGF, while it can reach the maximum value of 23 % in SIF. Analysis of drug release mechanism revealed two mainly distinct processes: erosion in SGF and diffusion in SIF. Furthermore, in vivo anticancer effect was evaluated in mice with orthotopic colon cancer model. After 28 days, compared to Tan IIA@β-CD group, the tumor volume and weight in EUR/AS/Tan IIA@β-CD group were decreased by 20.0 % and 34.6 %, respectively. Histological analyses showed that EUR/AS film significantly enhanced the available treatment against colon cancer cells. The proposed EUR/AS/Tan IIA@β-CD system shows great potential for colon-targeted drug delivery and enhancing the therapeutic efficacy of colon cancer.