Methods to decrease impurities from recombinant protein manufacturing processes

A method of producing a buffered solution of monoclonal antibodies (mAbs) with a reduced amount of non-aggregate product-related impurities (NAPRIs), the method comprising passing an initial buffered solution comprising:

• (a) mAbs, and (b) NAPRIs, through a synthetic depth filter comprising silica and polyacrylic fiber to produce the buffered solution of mAbs with the reduced amount of NAPRIs,
• wherein the NAPRIs comprise incompletely or incorrectly assembled mAb polypeptides,
• wherein the NAPRIs comprise high molecular weight (HMW) polypeptides having a molecular weight higher than the mAb,
• wherein the NAPRIs do not comprise aggregates, and
• wherein the reduced amount of NAPRIs is with respect to the amount of NAPRIs in the initial buffered solution before it has passed through the synthetic depth filter comprising silica and polyacrylic fiber.