FRACTIONATION METHOD

摘要

Provided herein is a novel method of purifying an IgG antibody from a preparation by use of an electropositive membrane having a defined porosity.

主权项

1. A method of purifying an IgG antibody from a preparation containing the antibody and contaminants comprising:
(a) contacting the preparation with an electropositive membrane having a porosity that retains at least 50% of non-adsorbed solutes with a hydrodynamic diameter greater than a selected size but permits passage of non-adsorbed solutes with a hydrodynamic diameter less than the selected size, wherein the selected size is about 10 nm, further wherein during at least a portion of the contacting step the preparation comprises (i) a salt at a concentration less than about 50 mM and a pH in a range from about 3 to within about 0.5 pH units of-an isoelectric point of a most alkaline glycoform of the IgG antibody in the preparation; or (ii) a salt at concentration greater than about 50 mM and a pH from about 3 to about 9; and (b) a final contacting step defined by either (i) an absence of excess salt in the preparation or a non-zero salt concentration in the preparation of not greater than 20 mM, and (ii) a pH value in a range from about 5 to within about 0.5 pH units of the isoelectric point of the most alkaline glycoform of the IgG antibody.