Formoterol fumarate (Eformoterol Hemifumarate), an effective, specific and long-acting β2-adrenoceptor agonist, is utilized in the treatment of chronic obstructive pulmonary disease(COPD) and asthma.

In guinea pig lungs, Formoterol at a concentration of 100 mg/mL inhibits Platelet-Activating Factor (PAF)-induced eosinophil aggregation and suppresses Porcine Pancreatic Elastase (PPE) activity for 2-4 hours. In conscious guinea pigs, Formoterol dose-dependently inhibits histamine-induced plasma protein leakage and bronchoconstriction. Significant inhibition of histamine-induced effects was observed at doses of 10 mg/mL and 100 mg/mL. Additionally, a higher concentration of Formoterol is required to inhibit neutrophil aggregation (induced by Lipopolysaccharides) compared to its ability to suppress granulocyte-independent PPE (induced by histamine).

Formoterol is a high-affinity, selective β2-adrenergic receptor agonist that effectively relaxes airway smooth muscles. Similar to salbutamol and salmeterol, it relaxes guinea pig trachea and human bronchi in vitro in a concentration-dependent manner and inhibits the release of antigen-induced inflammatory mediators in human lung slices.