Increased antitumor efficacy of ginsenoside Rh2 via mixed micelles: in vivo and in vitro evaluation

The aim of this work is to apply Solutol® HS15 and TPGS to prepare self-assembled micelles loading with ginsenoside Rh2 to increase the solubility of ginsenoside Rh2, hence, improving the antitumor efficacy. Ginsenoside Rh2-mixed micelles (Rh2-M) were prepared by thin film dispersion method. The optimal Rh2-M was characterized by particle size, morphology, and drug encapsulation efficiency. The enhancement of in vivo anti-tumor efficacy of Rh2-M was evaluated by nude mice bearing tumor model. The solubility of Rh2 in self-assembled micelles was increased approximately 150-folds compared to free Rh2. In vitro results demonstrated that the particle size of Rh2-M is 74.72 ± 2.63 nm(PDI = 0.147 ± 0.15), and the morphology of Rh2-M is spherical or spheroid, and the EE% and LE% are 95.27 ± 1.26% and 7.68 ± 1.34%, respectively. The results of in vitro cell uptake and in vivo imaging showed that Rh2-M could not only increase the cell uptake of drugs, but also transport drug to tumor sites, prolonging the retention time. In vitro cytotoxicity and in vivo antitumor results showed that the anti-tumor effect of Rh2 can be effectively improved by Rh2-M. Therefore, Solutol® HS15 and TPGS could be used to entrapping Rh2 into micelles, enhancing solubility and antitumor efficacy.