A Liquid Formulation of a Long-acting Erythropoietin Conjugate

Erythropoietin (EPO) is a glycoprotein that acts as a cytokine for erythrocyte precursors in the bone marrow, thus, being regulating erythropoiesis. Since polypeptides such as EPO are less stable, a breakthrough for protein drugs is needed. To avoid these limitations, a long-acting conjugate was developed in this study, where we aimed to formulate a long-acting EPO conjugate consists of EPO linked to the immunoglobulin Fc fragment. Here we performed RP-HPLC and SE-HPLC analyses and biological activity assays after buffer exchange under various conditions for the development of liquid stabilizer formulations of a long-acting EPO conjugate and to find conditions that its maintain purity and activity. First, the ability of various stabilizers to stabilize the long-acting EPO conjugate was analyzed, and it was confirmed that a specific stabilizer (polysorbate, mannitol, and sodium chloride)maintained the long-acting EPO conjugate. In addition, following long-term storage stability, it was confirmed that the liquid formulation kept the long-acting EPO conjugate stable at 4ºC for 12 months. Even without neutral amino acids, the liquid formulation from this study can provide excellent storage stability for EPO, making it more economically beneficial than other stabilizers and lyophilizing agents.