Transport Characteristics of Asymmetric Cellulose Triacetate Hemodialysis Membranes

Abstract

Aims: The objective of this study was to compare the transport characteristics of highly asymmetric cellulose triacetate (ATA™) membranes with that of both symmetric cellulose triacetate and asymmetric polysulfone membranes. Methods: Data were obtained for solute clearance and sieving coefficients of vitamin B₁₂ and a range of polydisperse dextrans using ATA™ SOLACEA-25H and Optiflux F250NR polysulfone dialyzers. Results for these, and the CT190 symmetric cellulose triacetate dialyzer, were analyzed using available membrane transport models. Results: The ATA™ had the largest solute clearance, although the homogeneous CT190 dialyzer had the highest sieving coefficients. These differences were a direct result of the differences in the underlying membrane morphology, with the asymmetric ATA™ membrane providing much higher diffusive transport rates (and thus higher solute clearance). Conclusions: These results demonstrate the importance of membrane morphology on dialyzer transport and provide important insights into the effective clinical performance observed with the highly asymmetric ATA™ dialyzers.

Effects of Plasma Proteins on the Transport and Surface Characteristics of Polysulfone/Polyethersulfone and Asymmetric Cellulose Triacetate High Flux Dialyzers

“…Experiments were performed using the high flux dialyzers shown in Table 1. The transport characteristics of these dialyzers (before exposure to blood/ serum) have been discussed by Kim et al (10). All dialyzers had 2.5 m 2 effective surface area.…”

“…The solute clearance was evaluated from data for the solute concentration in the feed reservoir as a function of time as discussed by Kim et al (10). PBS (without any dextrans) was used as the dialysate in a single-pass mode.…”

“…Additional details on the experimental methods are available in the literature (10). Column calibration was performed using narrow molecular weight dextran standards (American Polymer Standards Mentor, OH, USA) both before and after sample analysis.…”

“…The values of the vitamin B 12 clearance for the three dialyzers were similar, with values ranging from a high of K 5 260 6 6 mL/min for the SOLACEA-25H to a low of K 5 243 6 7 mL/min for the Optiflux F250NR, with the ELISIO-25H having a B 12 clearance of 258 6 6 mL/ min (mean values 1/the standard deviation for at least 3 repeat measurements). In each case, the dextran concentrations were evaluated from narrow slices of the SEC chromatographs, with the clearance then determined from data for the dextran concentration as a function of time as discussed by Kim et al (10). In each case, the dextran concentrations were evaluated from narrow slices of the SEC chromatographs, with the clearance then determined from data for the dextran concentration as a function of time as discussed by Kim et al (10).…”

“…The dextran and dialysate solutions were circulated through the blood and dialysate regions using peristaltic pumps (Cole-Parmer) at flow rates of 400 and 600 mL/min, respectively, in a countercurrent flow configuration. The solute clearance was evaluated from data for the solute concentration in the feed reservoir as a function of time as discussed by Kim et al (10). Dextran sieving coefficients were evaluated by pumping a 1.0 g/L solution of the mixed dextrans through the dialyzer lumen at a feed flow rate of 400 mL/min, with the permeate flow rate controlled using a Masterflex peristaltic pump connected to the dialysate outlet port.…”