Salmeterol Xinafoate

Salmeterol xinafoate is a selective and long-acting β₂-adrenergic receptor agonist. In vitro and in vivo studies demonstrate that salmeterol is selective for β₂- adrenergic receptors compared with isoproterenol [I0260], which has approximately equal agonist activity on β₁ and β₂- adrenergic receptors. The pharmacologic effects of β₂-adrenergic receptor agonist agents, including salmeterol, attributable to stimulation of intracellular adenyl cyclase, the enzyme that catalyzes the conversion of adenosine triphosphate (ATP) [A0157 (2Na salt)] to cyclic-3’,5’-adenosine monophosphate (c-AMP) [A2381, A2112 (Na salt)]. Increased c-AMP levels cause relaxation of bronchial smooth muscle and inhibition of release of inflammatory mediators from cells, especially from mast cells.
The mechanism of action for long-acting is explained as follows. Salmeterol consists of a saligenin ethanolamine “head” with a large lipophilic “tail” or side chain. Because of the side chain is anchored at the exo-site, the active “head” portion continually attaches to and detaches from the receptor site. (The product is for research purpose only.)