The invention provides a method for producing a host cell protein-(HCP) reduced antibody preparation from a mixture comprising an antibody and at least one HCP, comprising an ion exchange separation step wherein the mixture is subjected to a first ion exchange material, such that the HCP-reduced antibody preparation is obtained.本發明提供一種從包含抗體及至少一種宿主細胞蛋白質(host cell protein;HCP)之混合物中製備HCP經減少之抗體製劑的方法,該方法包含離子交換分離步驟,其中該混合物係經受第一離子交換材料,如此HCP經減少之抗體製劑便可獲得。