Oridonin-loaded poly(ε-caprolactone)–poly(ethylene oxide)–poly(ε-caprolactone) copolymer nanoparticles: Preparation, characterization, and antitumor activity on mice with transplanted hepatoma

Abstract

The aim of the present study was to develop a polymeric delivery system for water-insoluble drug oridonin. Amphiphilic block copolymers, poly(ε-caprolactone)–poly(ethylene glycol)–poly (ε-caprolactone) (PCL–PEO–PCL), were synthesized by ring-opening polymerization of caprolactone initiated by the hydroxyl groups of poly(ethylene glycol)6000 (PEG-6000) with stannous octoate as catalyzer. Oridonin-loaded PCL–PEO–PCL copolymer nanoparticles (ORI–PCL–PEO–PCL–NPs) were prepared by the interfacial deposition method. The mean particle size of the drug-loaded nanoparticles was 97.5 nm and the zeta potential was − 25 mV. The entrapment efficiency and actual drug loading of the nanoparticles were 87.52% ± 1.86% and 8.63% ± 0.49%, respectively. The antitumor activity of ORI–PCL–PEO–PCL–NPs was evaluated by measuring changes in tumor volumes, tumor weights, and survival rates of mice with grafted hepatoma (H22). The results indicated that ORI–PCL–PEO–PCL–NPs prolonged the survival time of mice and exhibited higher therapeutic efficacy compared with free oridonin. Thus, ORI–PCL–PEO–PCL–NPs may be used as a promising delivery system for liver cancer treatment.