Poly(trimethylene carbonate)-b-poly(ethylene glycol) diblock copolymer micelles for hydrophobic drug delivery: The effect of hydrophilic/hydrophobic segment length on micellar properties and drug loading

The encapsulation and release of hydrophobic drugs from polymersomes are of great importance in drug delivery. A significant challenge is to enhance the encapsulation capacity of finding better drug-polymer compatibility. Herrin, poly(trimethylene carbonate)-b-poly(ethylene glycol) (PTMC-PEG) diblock copolymers were successfully synthesized by ring opening polymerization of trimethylene carbonate using monomethoxy poly(ethylene glycol) (mPEG) as macro-initiator and stannous octoate as catalyst. The resulting diblock copolymer were characterized by 1 H NMR, FTIR, GPC, and DSC techniques. Blank and paclitaxel (PTX) loaded micelles was prepared by co-solvent evaporation method and characterized by transmission electron microscope (TEM) and dynamic light scattering (DLS). The influence of hydrophilic/hydrophobic segment length to drug loading and release was explored. All micelles have the sustained hydrophobic drug release properties of the micelles. Moreover, the cytotoxicity of micelles was evaluated by MTT and live-dead cell staining assay using L929 cell lines, showing the good biocompatibility. Therefore, PTMC-PEG micelles could be a suitable material for the loading and releasing of hydrophobic drugs.