Investigation of endotoxin adsorption with polyether polymer alloy dialysis membranes

Endotoxin (ET) in the dialysate is known to be adsorbed by dialysis membranes made of polyether polymer alloy (PEPA) and polymethylmethacrylate (PMMA). In the present study, the effect of polyvinylpyrrolidone (PVP) localization of the PEPA dialysis membrane on the adsorption of ET was investigated. The compounding of PVP in the PEPA membrane was changed, and hydrophobic membrane in both blood side and dialysate side, and hydrophilic membrane in only the blood side were used. Adsorption was evaluated by filling the contaminated dialysate inside and outside the membrane after priming with physiological saline, and determining the ET concentration in the blood side and dialysate side of dialysis membrane during the 240 min period from the start of filling the contaminated dialysate. With the PEPA membranes investigated, ET was significantly adsorbed to the hydrophobic side and was not adsorbed to the blood side of hydrophilic type membrane. These results suggest that in addition to electrostatic action attributable to the compounding of hydrophilic agent PVP to the dialysis membrane, the distribution of PVP that was compounded and the potential of the membrane itself may cause differences in adsorption of ET.