L-proline-stabilized human IgG: Privigen® 10% for intravenous use and Hizentra® 20% for subcutaneous use.

Liquid IgG preparations are preferred over lyophilized preparations because reconstitution is not required. Formation of dimers and aggregates in liquid preparations increases adverse effects and limits the shelf life of most liquid IgG products. Improved understanding of the binding interactions in IgG dimers and aggregates led to the selection of L-proline at pH 4.8 as an excipient that would minimize their formation. CSL Behring has developed the L-proline-stabilized products Privigen®, a 10% IgG solution for intravenous use; and Hizentra®, a 20% solution for subcutaneous use. The former has the longest shelf life of any liquid IgG in the USA--36 months, and the latter is the most concentrated IgG available. These improvements, which translate into improved convenience for pharmacies and patients, were achieved with no compromise in safety, efficacy or tolerability of the products.