COPD Treatment with Beta 2-Adrenoreceptor Agonists: Medicinal Perspectives and Recent Advances

Chronic Obstructive Pulmonary Disease (COPD) is a respiratory condition defined by persistent bronchitis, emphysema, and structural remodelling. The number of cases has risen globally; however, limited viable remedies exist. It is linked to airway blockage, oxidative stress, chronic conditions, inflammation, excessive mucus production, and increased autophagy and cellular senescence. Beta-2 adrenergic receptors (β₂-ARs) play a significant role in both the aetiology and management of COPD. Beta-2 agonists (particularly long-acting beta-agonists, or LABAs) are preferable in COPD therapy due to their powerful bronchodilation, rapid onset, prolonged duration, and potential synergistic effects with other medications. They are well-tolerated and effective in improving the quality of life and reducing exacerbations, making them an essential component of COPD treatment. Currently, there are fewer bronchodilators that have been found to be effective. This leads to an exploration of novel, long-acting, and ultra-long-acting drugs for the management of COPD. This article provides an extensive overview of natural β₂ agonists. The current study emphasizes the rational development of lead candidates, including trantinterol, isopropyl, tert-butyl, and heterocyclic ring 2-amino-2-phenylethanol derivatives, 8-(2-amino-1-hydroxyethyl)-6-hydroxy-1,4- benzoxazine-3(4H)-one derivatives (non-substituted, methyl-substituted, dimethyl-substituted), 5- (2-amino-1-hydroxyethyl)-8-hydroxyquinolin-2(1H)-one analogues, indacaterol analogues, saligenin antedrugs, and saligenin alkoxyalkylphenyl sulfonamide derivatives, accompanied by molecular docking studies. This paper also highlights numerous structure-activity relationship investigations and various novel β₂ agonists currently in clinical trials and patents. The present review will significantly aid in fostering the research of COPD.