The invention provides a biopharmaceutical formulation including an aqueous solution having a propionate buffer with a pH from about 4.0 to about 6.0, at least one excipient and an effective amount of a therapeutic polypeptide. The propionate buffer can include a concentration selected from between about 1-50 mM, 2-30 mM, 3-20 mM, 4-10 mM and 5-8 mM. The therapeutic polypeptide included in a biopharmaceutical formulation of the invention can include an antibody, Fd, Fv, Fab, F(ab'), F(ab)