Injectable PEG/polyester thermogel: A new liquid embolization agent for temporary vascular interventional therapy.

Injectable poly(ethylene glycol) (PEG)/polyester thermogels exhibit superior injectability and unique thermoreversible sol-gel transitions compared with Onyx™, which is the only liquid embolic agent approved by the U.S. Food and Drug Administration. Herein, the feasibility of an injectable methoxy PEG-poly(d,l-lactide) copolymer (mPEG-PLA) thermogel for temporary vascular interventional therapy was evaluated in the large animal (swine) model for the first time. This mPEG-PLA polymer was soluble in water at a low temperature and exhibited a reversible sol-gel transition with increasing temperature. Meanwhile, the addition of an X-ray contrast agent did not significantly affect the gelation behavior of the thermogel but did confer excellent radiopacity, allowing intraoperative X-ray imaging guidance. In vivo experiments demonstrated that compared with traditional embolic agents, the mPEG-PLA thermogel required less preparation time and could be injected more conveniently during the operation. The temporary arterial embolization was achieved after the thermogel injection, yet the blocked arteries were recanalized 1 hour post-operation. Consequently, the mPEG-PLA thermogel shows some potential as a temporary pre-surgical embolic agent for tumor resection, but further researches including enhancing mechanical strength of gel are required to improve the embolization efficacy of PEG/polyester thermogel in the future.