Objective To investigate the physical properties and controlled release of Arsenic trioxide(As_2O_3) in 40% Lipiodol(LIP)
and ultra - fluid lipiodol(UFL) emulsion and suspension so as to guide the clinical administration.Methods Several types of emulsions and
suspensions were prepared using LIP or UFL and As_2O_3 by“pumping technique”. Physical stability of each preparation was examined macroscopically and microscopically. The drug release test was made through dialysis band from the phosphate buffer solution under the constant condition of 37℃±0.5℃, the As_2O_3 releasing rates were calculated by detecting the concentration of As_2O_3 in dialysis solution (releasing rate = concentration of As_2O_3 measured×100/As_2O_3 quantity in all×100 %).Results Separation and sedimentation in LIP or UFL As_2O_3 suspensions were presented after putting them rest for some time , the separation was easier in LIP suspension than that in UFL suspension. Separation between oil phase and water phase was presented immediately in both of emulsions without
emulsifier, the emulsions with emulsifier were more stable. As_2O_3 can be released slowly in LIP or UFL emulsions, the release of As_2O_3 was slower in their emulsions with emulsifier than in those without emulsifier. The release of As_2O_3 in their suspensions was faster.Conclusion Both LIP and UFL can serve as embolization materials and carrier of As_2O_3,and using their emulsions can increase the dose of As_2O_3 in order to improve therpeutic effect without concurrent increase of adverse reactions.