Efficient molecular mass fractionation of leukocyte extract by membrane separation

Abstract

The unique choice of a pair of membranes for a two-step ultrafiltration process of a leukocyte extract allowed to obtain from it an almost homogenous active product. This choice was based on the chromatographic analysis of the permeates after ultrafiltration of the extract using the polyamide hollow fibers VPU-15 (cut-off 15 kDa) and VPU-5 (cut-off 5 kDa) and a flat-sheet membrane produced from cellulose acetate UAM-150 (cut-off 5 kDa). The elution profiles of the permeates of the VPU-5 and UAM-150 membranes showed less outer similarity than the permeates of the VPU-5 and VPU-15 membranes: the hollow fibers VPU-5 and VPU-15 let through the same fractions, except for one more highly molecular fraction, according to the differences in the nominal selectivity of the membranes. The discovered similarity of the fractional composition of the permeates, which reflects the resemblance of the macro and microstructure of the membranes determined the pair of membranes (VPU-15 and VPU-5) which allowed for a successful molecular mass separation.