Lyophilized formulations for factor Xa antidote

A method for preparing a lyophilized formulation, comprising lyophilizing an aqueous solution comprising about 45 mM arginine, from 1% to 3% sucrose (w/v), from 2% to 8% mannitol (w/v), from about 0.01% to about 0.02% (w/v) polysorbate 80 and at least 5 mg/mL of a two-chain polypeptide comprising a first chain comprising the amino acid sequence of SEQ ID NO. 4, a second chain comprising the amino acid sequence of SEQ ID NO. 5, and a disulfide bond between a first Cysteine residue at position 98 (Cys98) of SEQ ID NO. 4 and a second Cysteine residue at position 108 (Cys108) of SEQ ID NO. 5, wherein the aqueous solution has a pH from 7.7 to 7.9.