A Process for Enhancing Selectivity and Limiting Plugging in Plasmafractionation for Apob Removal

Abstract

A new process using pressure and flow pulsations was investigated in the second stage of cascade filtration for ApoB removal. Due to enhanced filtration by the pulsations, the retentate flow vanished naturally without clamping the line, which reduced albumin and ApoA₁ losses. The performance of Eval 4A and cellulose PF100 filters in this case were compared with that of classical dead end mode at a plasma flux of 18 ml/(min m²). The apparent sieving coefficient for small proteins (albumin, ApoA₁) under pulsed conditions increased with increasing pressure instead of dropping as in dead end mode. In both cases the ApoB sieving coefficients remained below 0.02. These encouraging results were accompanied by a slower rise of transmembrane pressure showing a decrease of membrane plugging. Thus, the recovery of albumin and ApoA₁ is increased while ApoB removal remains constant, which improves the selectivity of the fractionation stage.