Preparation of in situ multifunctional traditional Chinese medicine thermosensitive microemulsion gel embolic agent for interventional therapy

Transcatheter arterial chemoembolization (TACE) is a minimally invasive procedure performed in interventional radiology to restrict a tumor's blood supply. Blood-vessel-embolic agents play key role on TACE. In the present work, we reported a Bletilla striata polysaccharide/poly (N-isopropylacrylamide) (BSP/PNIPAM) thermosensitive microemulsion gel loaded with magnetic icaritin (ICT) microemulsion (IS-MEs) as embolic agent (ISBP) for the first time. IS-MEs co-loaded with ICT and superparamagnetic iron oxide nanoparticles (SPIONs) were prepared by water titration method. The particle size of IS-MEs was 27.97 ± 0.25 nm, encapsulation efficiency was 97.18%, and presented a regular sphere under TEM. BSP/PNIPAM was prepared by free radical polymerization, which has good biocompatibility, excellent procoagulant function and dense microstructure. The lower critical solution temperature (LCST) of ISBP was 30 °C, which had excellent in vitro injection performance. The microscopic morphology of ISBP was loose and porous, the long-acting sustained-release time could reach 144 h, and the maximum ICT release was (48.6 ± 8.5) %. IPSBs with SPIONs exhibit desirable imaging properties and macrophage M1 polarization function. During the rabbit renal artery embolization, ISBP showed excellent distal vascular embolization performance and there was no obstruction or adhesion of the catheter. These results suggest that a novel in situ multifunctional traditional Chinese medicine thermosensitive microemulsion gel embolic agent has been developed with a potential application as a liquid embolic solution for TACE.