Design of amphiphilic PCL-PEG-PCL block copolymers as vehicles of Ginkgolide B and their brain-targeting studies.

The amphiphilic PEG-b-PCL block copolymers were synthesized by ring-opening polymerization. The specific and selective antagonists of platelet activating factor, Ginkgolide B (GB), was successfully encapsulated in the synthesized PEG-PCL nanoparticles (NPs) with high Encapsulation Efficiency and Drug Loading. The synthesis of different PEG-PCL copolymers were confirmed with FTIR and 1 H NMR spectra. The morphology and particles size distribution of cargo-free PEG-PCL NPs were studied by transmission electron microscope (TEM) analysis and Malvern laser particle analyzer. The bio-distribution and pharmacodynamics studies of GB were studied with Wistar mice as the animal models via tail injecting of GB-PEG-PCL NPs. Results from Malvern laser particle analyzer and TEM analysis illustrated that the cargo-free NPs showed narrow distribution and well separated particles size of about 60 nm in diameter. The in vitro experiment of GB-PEG-PCL NPs exhibited an extended release behavior. The bio-distribution data suggested that Tween-80 covered GB-PEG-PCL NPs showed a brain-targeting behavior. The pharmacodynamics results confirmed that the GB-PEG-PCL NPs had an obvious cerebral protection effect.