Determination of Iodixanol Hemodialysis Clearance Using a Novel In Vitro System

Abstract

The hemodialysis clearance of iodixanol, a new non-ionic, low-osmolar, radiographic contrast agent, was studied using an in vitro model. Whole human blood was obtained from healthy volunteers and modified by the addition of urea and saline to mimic uremic, anemic blood from renal failure patients. The blood was inoculated with iodixanol and dialyzed against a 135 SCE cellulose dialyzer and a Fresenius F5 polysulfone dialyzer. Urea and saline solutions were continuously replaced during the procedure. Each membrane was studied at a dialysate flow rate of 500 mL/min and at blood flow rates of 300 mL/min for the first two hours, 400 mL/min for the third hour, and 500 mL/min for the fourth hour of each dialysis run. Simultaneous arterial and venous blood samples were taken from each side of the dialyzer at specified times. Plasma iodixanol concentrations were assayed by HPLC. The cellulose and polysulfone membranes removed a total of 36.1% and 49.6% of iodixanol in four hours. Plasma iodixanol concentrations decreased monoexponentially, and the area-under-the-curve was 76% for the polysulfone membrane compared to the cellulose dialyzer. Iodixanol clearances ranged between 20 to 280 mL/min. It is concluded that this in vitro model is a convenient tool which is able to mimic clinical conditions, and that iodixanol is readily cleared by hemodialysis.