Patent attributes
A method of accurately separating immunoglobulin monomers by subjecting an immunoglobulin solution containing at least immunoglobulin monomers and immunoglobulin aggregates to cross-flow filtration using an ultrafiltration membrane, an ultrafiltration membrane module, and a cross-flow filtration apparatus. The method can separate immunoglobulin monomers by subjecting an immunoglobulin solution containing at least immunoglobulin monomers and immunoglobulin aggregates and having an immunoglobulin concentration of 1 to 150 g/L to cross-flow filtration using an ultrafiltration membrane having a molecular weight cut-off of 100,000 or more and less than 500,000 so that immunoglobulin monomers passes through the ultrafiltration membrane with a permeability of 80% or more while achieving a fractionation performance in which the permeability ratio of immunoglobulin dimers to immunoglobulin monomers that pass through the ultrafiltration membrane is 0.20 or less.
