Salmeterol-d5 is a deuterated labeled Salmeterol. Salmeterol (GR33343X) is a potent and selective human β2 adrenoceptor agonist. Salmeterol shows potent stimulation of cAMP accumulation in CHO cells expressing human β2, β1 and β3 adrenoceptors with pEC 50 s of 9.6, 6.1, and 5.9, respectively.