Selective separation method of aggregates from IgG solution by aqueous two-phase system.

Area of Science:

• Biochemistry
• Pharmaceutical Science
• Protein Chemistry

Background:

• Immunoglobulin G (IgG) aggregation is a critical issue in pharmaceutical development, potentially leading to immunogenicity.
• Current methods for removing small, soluble IgG aggregates from protein solutions are often complex and inefficient.

Purpose of the Study:

• To investigate the efficacy of an aqueous two-phase system (ATPS) for the selective removal of soluble IgG aggregates.
• To explore the partitioning behavior of IgG monomers and aggregates within an ATPS composed of polyethylene glycol (PEG) and dextran (DEX).

Main Methods:

• An aqueous two-phase system (ATPS) was formulated using polyethylene glycol (PEG) and dextran (DEX).
• The partitioning of immunoglobulin G (IgG) monomers and pre-formed soluble aggregates was analyzed in the PEG-DEX ATPS.
• The distribution of IgG species between the ATPS phases and the interface was quantified.

Main Results:

• Immunoglobulin G (IgG) monomers preferentially partitioned into either the PEG or DEX-rich phase.
• Nearly all small and soluble IgG aggregates were effectively extracted and localized at the interface between the two phases.
• The differential partitioning was attributed to the distinct solubilities of IgG monomers and aggregates in the PEG and DEX phases.

Conclusions:

• Aqueous two-phase systems (ATPS) utilizing PEG and DEX offer a simple and effective method for removing soluble IgG aggregates.
• This ATPS-based approach shows promise for improving the purity and safety of therapeutic protein preparations.
• The selective partitioning mechanism provides a novel strategy for protein aggregate purification.