Preparation and evaluation of PEG–PCL nanoparticles for local tetradrine delivery

To establish a satisfactory delivery system for local delivery of Tetradrine (Tet), four kinds of core-shell nanoparticles were prepared from di-block copolymer of methoxy poly(ethylene glycol)–polycaprolactone (MePEG–PCL) and tri-block copolymer of polycaprolactone–poly(ethylene glycol)–polycaprolactone (PCL–PEG–PCL). The physiochemical traits of the four kinds of nanoparticles including morphology, particle size, zeta-potential, drug-loading content, stability, and in vitro release profile were studied. We also evaluated the four kinds of nanoparticles by in vitro cellular uptake experiment, cytotoxicity assay against LoVo cells, and biocmpatibility study. Histoculture Drug Response Assay (HDRA), a more predictive method usually used to evaluate chemosensitivity was firstly applied in our study to evaluate the antitumor potency of polymeric nanoparticles. The current study showed that all the four kinds of copolymers exhibited remarkable in vitro antitumor effects, especially in HDRA assay. The configuration and composition of the copolymers were important for the properties and functions of the nanoparticles. Nanoparticles prepared from the di-block copolymer with a particle size around 300 nm and the hydrophobic composition about 80% was determined as the most effective drug carrier for further studies.