Experimental Study On In Situ Liquid Crystal Of Phytotriol As A New Liquid Embolic Agent

Objective:The purpose of this study was to prepare a novel liquid embolic agent by using sinomenine and 5-fluorouracil as model drugs and phytanyltriol as carrier material by using the synergistic effect of embolization and chemotherapy.The new embolic agent had multiple effects such as sustained release,targeting,embolization and chemotherapy.Methods:Three prescription phytantriol in situ liquid crystals were selected to prepare a stable and reliable precursor injection-liquid embolic agent according to the literature review and the ternary phase diagram drawn by the previous research group.The phase transition behavior of phytotriol in situ liquid crystals was observed by means of in vitro and in vivo gelation experiments,polarized light microscopy characterization,small angle x-ray scattering characterization and in vitro injection experiments,gelation water content,gelation time and rheological properties to investigate its potential as a liquid embolic agent.In order to provide a theoretical basis for in vivo experiments,the biocompatibility of phytantriol in situ liquid crystals was investigated by cytotoxicity,blood compatibility and histocompatibility.In vitro anti-cancer experiments were conducted to study the interaction of sinomenine with5-fluorouracil on Hep G2 cells to establish a complete in vitro assay for in vitro release of phytantriol in situ liquid crystals.In vitro and in vivo swelling,degradation experiments and embolization experiments were carried out to investigate the effect of phytantriol in situ liquid crystal embolization.Rabbit ear embolization experiments were performed to observe the in vivo pharmacokinetics of sinomenine and5-fluorouracil.Results:Three prescription liquid embolic agents（P₁:phytantriol:ethanol:water=64:16:20;P₂:phytantriol:ethanol:water=48:32:20;P₃:phytantriol:ethanol:water=16:64:20）were clear and transparent liquid state.They had good gelling properties in vitro and in vivo.The liquid crystal gel formed in situ after water absorption was cubic phase and had good injectability.The gelation water content was 73.33±11.55,226.67±11.55,553.33±30.55μL,and the gelation time was 9.21±1.86,15.90±0.26,20.97±20.87s,respectively.It showed liquid property before in situ and solid property after in situ,which had a certain embolic potential.All the liquid embolic agents had slight hemolysis,P₁ had good histocompatibility,P₂ and P₃ had certain stimulation reaction,and the cytotoxic reaction was the first order,which could be used for embolizing in vivo.Sinomenine and 5-fluorouracil had synergistic inhibitory effects on Hep G2 cells in a large concentration range,and in vitro release studies showed that the cumulative release of sinomenine and 5-fluorouracil was more than90%within 7 days and conformed to the first-order release kinetic model.In vitro and in vivo degradation and embolization experiments showed that all the prescriptions can effectively embolize blood vessels and had the effect of permanent embolization.The pharmacokinetic experiments showed that P₁ could significantly prolong the half-life of sinomenine and 5-fluorouracil（more than three times that of the solution group）and the residence time in vivo（more than twice times that of the solution group）.The blood concentration can also be maintained for a long time.Conclusion:The liquid embolic agent prepared in this study had a certain embolic potential,and with the synergistic action of sinomenine and 5-fluorouracil,it can have multiple effects such as sustained release,embolization and chemotherapy,etc.It can be used as a potential treatment for hepatic arterial chemoembolization.