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Abstract: PO1157

New Polymeric Dialysis Membrane with EndexoTM Surface Modifying Macromolecule

Session Information

Category: Dialysis

  • 701 Dialysis: Hemodialysis and Frequent Dialysis


  • Ho, Chih-Hu, Fresenius Medical Care North America Ogden, Ogden, Utah, United States
  • Fisher, Colleen M., Fresenius Medical Care North America Ogden, Ogden, Utah, United States
  • Mullon, Claudy, Fresenius Medical Care North America Ogden, Ogden, Utah, United States

Surface-modifying macromolecules (SMM) may improve the hemocompatibility of hemodialyzers. We report the in vitro characterization of a new Optiflux® EnexaTM dialyzer containing a membrane with a fluorinated polyurethane SMM (EndexoTM).


Hollow fiber membranes were manufactured by mixing polysulfone (PS), polyvinylpyrrolidone (PVP), and the EndexoTM SMM. Contact angle and zeta potential were used to characterize the surface of the membrane compared to hollow fiber membranes from Optiflux® F160 dialyzers without EndexoTM SMM. In vitro hemocompatibility was assessed using freshly collected heparinized human blood. An in vitro simulation model was used to mimic the clinical frequency of blood contact with the dialyzer, and to evaluate platelet and complement activations as well as coagulation factors. Comprehensive biocompatibility evaluations and toxicological risk assessment were performed on EndexoTM SMM and the dialyzer, based on ISO 10993 guidelines.


Surface characterization of the membrane revealed a slight increase in hydrophobicity in the inner lumen and up to 40% increase in the outer lumen, and a lower zeta potential on the blood side (-1.9 meV) compared to the control membrane (-12.9 meV). In vitro simulations with the Optiflux® Enexa™ dialyzer showed 58% and 67% lower platelet count reduction and platelet activation than observed with Optiflux® dialyzer. Extractable/leachable testing using 17.2% and 39.1% ethanol on the Optiflux® Enexa™ dialyzer resulted in margin of safety (MOS) values of > 1. Biological tests received passing/acceptable results.


Improved membrane surface characteristics and hemocompatibility performance were observed in vitro using a new dialyzer containing the EndexoTM fluorinated polyurethane surface modifying molecule. Based on the biocompatibility data, and toxicological assessment of exposure to chemicals from the device, the weight-of-evidence suggests that the concern for adverse effects following the intended use of the Dialyzer with EndexoTM is minimal.