PCL-based thermo-gelling polymers for in vivo delivery of chemotherapeutics to tumors

•The synthesis of a poly(ether ester urethane)s comprising poly(ε-caprolactone), poly(ethylene glycol), and poly(propylene glycol) is described.•This polymer possessed a critical thermo-gelation concentration of 4 wt%.•In vitro paclitaxel and doxorubicin release studies and showed that release of about 2 weeks can be obtained.•In vivo intratumoral injection of drug-loaded thermo-gel showed that it inhibited the growth of tumors.

The synthesis of a multiblock poly(ether ester urethane)s comprising poly(ε-caprolactone), poly(ethylene glycol), and poly(propylene glycol) segments is described. We found that this polymer possessed a critical thermo-gelation concentration of 4 wt%. Molecular characterization of the polymer was performed in terms of molecular weight determination, chemical composition elucidation and functional group determination using GPC, NMR, and FTIR. We carried out in vitro paclitaxel and doxorubicin release studies and demonstrated that sustained therapeutic release of about 2 weeks can be obtained with this system. A nude mice model of tumor was developed and intratumoral injection of therapeutic-loaded thermo-gel demonstrated that PTX-loaded thermo-gel effectively inhibited the growth of tumors.