Diamonds in the rough: Protein crystals from a formulation perspective

The focus of the present review is to address the use of protein crystals i n formulation design. Although this idea has been present for some time, i. e., insulin crystals were first reported back in 1920s, macromolecular crys tallization has not received as much attention as the other methods for sta bilizing protein drug candidates. The prospective potential of crystalline protein formulations in light of new advances in the field of macromolecula r crystallization was reviewed, and the basic concepts and the tools now av ailable for developing protein crystals into drug formulations are introduc ed. In addition, formulation challenges and regulatory demands, along with examples of current applications of protein crystals, are presented.