Formulations and methods are provided for improving the stability upon exposure to aqueous media of polypeptides present in non-aqueous suspension vehicles. In particular aspects of the invention, formulations are provided that comprise a complex of a metal ion and a polypeptide suspended in a non-aqueous, biocompatible suspension vehicle. Aggregation of individual polypeptide molecules is reduced when aqueous media is introduced to such formulations, serving to stabilize the polypeptide.
