SEREVENT DISKUS contains salmeterol xinafoate as the racemic form of the 1-hydroxy-2-naphthoic acid salt of salmeterol. The active component of the formulation is salmeterol base, a selective beta2-adrenergic bronchodilator. The chemical name of salmeterol xinafoate is 4-hydroxy-?1-[[[6-(4-phenylbutoxy)hexyl]amino]methyl]-l,3-benzenedimethanol, l-hydroxy-2-naphthalenecarboxylate. Salmeterol xinafoate has the following chemical structure: