A method for preparing a protein or peptide powder is provided that includes spray drying a solution including more than, e.g., about 50 mg/mL of a protein or peptide (e.g., an antibody or antigen binding protion thereof), and at least one excipient. Also provided are stable powdered compositions including a protein and an excipient having less than, e.g., about 6% residual moisture.本發明提供一種製備蛋白質或肽粉末之方法,其包括將一種包括大於(例如)約50mg/mL之蛋白質或肽(例如抗體或其抗原結合部分)及至少一種賦形劑之溶液噴霧乾燥。本發明亦提供包括蛋白質及賦形劑之穩定粉末組合物,其具有小於(例如)約6%之殘餘水分。