Tarafenacin D-tartrate (SVT-40776 D-tartrate) is a selective and potent muscarinic acetylcholine M3 receptor antagonist used in the study of overactive bladder and bronchial disorders.

D-tartrate Tarafenacin was more selective for M(3) receptors than for M(2) receptors (Ki = 0.19 nmol.L(-1) for M(3) receptor affinity). Of the anticholinergic drugs tested, tarafenacin tartrate had the strongest inhibitory effect on carbachol-induced bladder contraction but did not affect atrial contraction over the same concentration range. Tarafenacin D-tartrate had the highest selectivity (199-fold) for urine and heart.The binding affinity of tarafenacin D-tartrate for the M5 mAChR (K(d) = 0.4 nM) was much higher than that of solifenacin (K(d) = 31 nM) for the same receptor.The binding affinity of tarafenacin D-tartrate for the M5 mAChR was much higher than that for solifenacin (K(d) = 31 nM). The calculated change in free energy of binding from solifenacin to tarafenacin tartrate (-2.3 ± 0.3 kcal/mol) agrees well with the experimentally derived change in free energy of binding (-2.58 kcal/mol), suggesting that our modeled structure of the M5 mAChR and its complex with the antagonist is reliable [1][2].

Tarafenacin D-tartrate inhibited 25% of spontaneous bladder contractions at a very low dose (6.97 microg.kg(-1) i.v) in the guinea pig in vivo model, without affecting arterial blood pressure [1].