Sustained co-delivery of gemcitabine and cis-platinum via biodegradable thermo-sensitive hydrogel for synergistic combination therapy of pancreatic cancer

Pancreatic cancer is one of the most devastating cancers with poor prognosis and no significant change in the survival rate over the past decades. Localized targeted drug delivery through interventional endoscopic ultrasonography-guided fine-needle injection (EUS-FNI) is an attractive and minimally invasive strategy for inoperable pancreatic cancer. An injectable in-situ formed long-lasting drug delivery system is a promising alternative for the localized treatment of pancreatic cancer via EUS-FNI. Here, a biodegradable thermo-sensitive copolymer hydrogel for the co-delivery of anticancer agents gemcitabine (GEM) and cis-platinum (DDP) was developed. This hydrogel is a free flowable liquid at room temperature that changes into a semi-solid hydrogel following injection in response to the physiological temperature. Both in vitro and in vivo drug release behaviors indicate sustained drug release of this delivery system. Synergistic cellular proliferation inhibition and desirable apoptosis promotion have been found when pancreatic cancer Bxpc-3 cells were co-cultured with this GEM-DDP/hydrogel system. After a single intratumoral injection, the dual-drug loaded hydrogel formulation exhibited superior anti-tumor efficacy and minimized systemic side effect on pancreatic cancer xenograft mouse model in comparison to the intravenously injected free GEM and DDP combination. In addition, a strong synergistic therapeutic effect of the GEM-DDP/hydrogel system against pancreatic cancer has been found in vitro and in vivo compared to the single-drug loaded hydrogel composites. The obtained findings suggest this developed thermo-sensitive copolymer hydrogel system as a potential universal carrier for the localized targeted delivery of multi-drugs, for use in a variety of inoperable solid tumors.