title: Sorbitol crystallization-induced aggregation in frozen mAb formulations.
abstract: Sorbitol crystallization-induced aggregation of mAbs in the frozen state was evaluated. The effect of protein aggregation resulting from sorbitol crystallization was measured as a function of formulation variables such as protein concentration and pH. Long-term studies were performed on both IgG1 and IgG2 mAbs over the protein concentration range of 0.1-120 mg/mL. Protein aggregation was measured by size-exclusion HPLC (SE-HPLC) and further characterized by capillary-electrophoresis SDS. Sorbitol crystallization was monitored and characterized by subambient differential scanning calorimetry and X-ray diffraction. Aggregation due to sorbitol crystallization is inversely proportional to both protein concentration and formulation pH. At high protein concentrations, sorbitol crystallization was suppressed, and minimal aggregation by SE-HPLC resulted, presumably because of self-stabilization of the mAbs. The glass transition temperature (Tg ') and fragility index measurements were made to assess the influence of molecular mobility on the crystallization of sorbitol. Tg ' increased with increasing protein concentration for both mAbs. The fragility index decreased with increasing protein concentration, suggesting that it is increasingly difficult for sorbitol to crystallize at high protein concentrations.
authors.affiliation: Amgen Inc., One Amgen Center Dr, Thousand Oaks, California, 91320.
authors.forename: Deirdre Murphy
authors.initials: DM
authors.lastname: Piedmonte
authors.forename: Alison
authors.initials: A
authors.lastname: Hair
authors.forename: Priti
authors.initials: P
authors.lastname: Baker
authors.forename: Lejla
authors.initials: L
authors.lastname: Brych
authors.forename: Karthik
authors.initials: K
authors.lastname: Nagapudi
authors.forename: Hong
authors.initials: H
authors.lastname: Lin
authors.forename: Wenjin
authors.initials: W
authors.lastname: Cao
authors.forename: Susan
authors.initials: S
authors.lastname: Hershenson
authors.forename: Gayathri
authors.initials: G
authors.lastname: Ratnaswamy
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000737:chemistry* / Q000378:metabolism; D002151:Calorimetry / Q000379:methods; D002626:Chemistry, Pharmaceutical; D003460:Crystallization; D005615:Freezing; D007074:Immunoglobulin G / Q000737:chemistry / Q000378:metabolism; D066329:Protein Aggregates / Q000502:physiology; D013012:Sorbitol / Q000737:chemistry* / Q000378:metabolism
chemical_list: D000911:Antibodies, Monoclonal; D007074:Immunoglobulin G; D066329:Protein Aggregates; D013012:Sorbitol
keywords: HPLC; X-ray diffraction; calorimetry (DSC); crystallization; excipients; glass transition temperature; mAb; protein aggregation; protein formulation; stabilization