Long-circulating doxorubicin and schizandrin A liposome with drug-resistant liver cancer activity: preparation, characterization, and pharmacokinetic

The selectivity of chemotherapeutic agents for liver cancer is poor. When they kill tumour cells, they produce serious adverse reactions in the whole body and multidrug resistance (MDR) is also a major hurdle in liver cancer chemotherapy. Combination therapy is a useful method for overcoming MDR and reducing toxic and side effects. In this study, we developed a long-circulating codelivery system, in which doxorubicin (DOX) and schizandrin A (SchA) are combined against MCF-7/ADR cells. The DOX-SchA long-circulating liposome (DOX-SchA-Lip) was prepared using ammonium sulphate gradient method. The two drugs were co-encapsulated into the distearoyl phosphatidylethanolamine-polyethylene glycol (DSPE-mPEG2000) liposome and the liposome had an average particle size of (100 ± 3.5) nm and zeta electrical potential of (-31.3 ± 0.5) mV. The average encapsulation rate of DOX was 97.98% and that of SchA was 86.94%. DOX in liposome had good sustained-release effect. The results showed that DOX-SchA-Lip could significantly prolong the half-life (t_1/2z) of the DOX and SchA, increase their circulation time in vivo, improve its bioavailability and reduce their side effects. Liposome can effectively induce early apoptosis of HepG2/ADR cells and the cell cycle was blocked in S-phase by DOX-SchA-Lip in a dose-dependent manner. The IC₅₀ of compound liposome to HepG2 and HepG2/ADR were 0.55 μmol/L and 1.38 μmol/L, respectively, which could significantly reverse the resistance of HepG2/ADR and the reversion multiple was 30.28. It was verified that DOX-SchA-Lip can effectively kill tumour cells and reverse MDR.