Varenicline-d4 is intended for use as an internal standard for the quantification of varenicline by GC- or LC-MS. Varenicline is a full agonist of α7 subunit-containing neuronal nicotinic acetylcholine receptors (nAChRs; EC50 = 18 μM) and a partial agonist of α4β2 subunit-containing nAChRs (EC50 = 2.3 μM). Formulations containing varenicline have been used as aids in smoking cessation.
