Stabilization of proteins in dry powder formulations using supercritical fluid technology

Therapeutic proteins have become essential in the treatment of many diseases. Their formulation in dry form is often required to improve their stability. Traditional freeze-drying or spray-drying processes are often harmful to labile proteins and could be replaced by supercritical fluid (SCF) drying to produce particles with defined physicochemical characteristics in a mild single step. A survey of the current SCF drying processes for proteins is presented to give insight into the effect of SCF drying on protein stability and to identify issues that need further investigation. Methods used for drying aqueous and organic protein solutions are described. In particular, effects of process and formulation parameters on particle formation and protein stability are discussed. Although SCF methodology for drying proteins is still in its infancy, it can provide a serious alternative to existing drying methods for stabilizing proteins.