Kinetics of anticoagulant binding to continuous hemofilter membranes

Abstract

 To date, there have been no adequate studies examining the kinetics of anticoagulant binding to the continuous hemofilter membranes used in continuous blood purification therapy. In this study, we compared the binding kinetics of conventional heparin (CH), argatroban (ARG), and nafamostat mesilate (NM) with various types of continuous hemofilter membranes [polyacrylonitrite (PAN), polymethylmethacrylate (PMMA), polysulfone (PS), and polyamide (PA)]. In-circuit circulation was conducted according to a recirculation batch method. Each drug concentration in the test solution was monitored up to 24 h after the in-circuit circulation, and amounts of the bound drug were calculated. There was little binding of CH to any of the membranes examined at 24 h after in-circuit circulation (383–1222 units/m²), except PA (2717 units/m²). ARG bound largely to PS (61.9 mg/m²) and slightly to PMMA (6.9 mg/m²). NM bound PAN (55.3 mg/m²) > PS (38.0 mg/m²) > PMMA (7.7 mg/m²). Binding of NM to PA was not detected. Our study suggested that the degree of anticoagulant binding depended on characteristics of the continuous hemofilter membranes. Accordingly, the combination of the type of membranes and the dose of anticoagulants should be carefully chosen in continuous blood purification therapy.