Arformoterol tartrate is the tartrate salt of arformoterol, a highly selective long-acting β₂-adrenergic agonist used as an active pharmaceutical ingredient (API) in nebulized formulations for the long-term maintenance treatment of chronic obstructive pulmonary disease (COPD), including chronic bronchitis and emphysema. It relaxes bronchial smooth muscle to improve airflow and reduce symptoms like wheezing, dyspnea, and cough. This high-purity (≥97.5%) research-grade chemical, appearing as a white to pale brown solid and confirmed by IR and NMR, is intended for pharmaceutical research, development, and manufacturing, not direct clinical use.