METHOD OF PREPARING ALPHA-1 PROTEINASE INHIBITOR

Disclosed is purification of á-1 proteinase inhibitor (á-1 PI) from solutions comprising á-1 PI. This is accomplished using hydrophobic interaction chromatography (HIC). In some embodiments, purification of á-1 PI is accomplished by precipitation of contaminating proteins from a starting solution comprising á-1 PI, such as human plasma, followed by anion exchange resin chromatography prior to HIC. Further purification may be accomplished by an optional cation exchange chromatography subsequent to anion exchange chromatography but prior to HIC. Some embodiments of the invention also include virus removal and/or inactivation by methods such as nano filtration and such as contact with a non-ionic detergent. The methods of the present invention result in greater yield, purity, and pathogenic clearance of plasma fractions than known methods.