(Rac)-5-Hydroxymethyl Tolterodine ((Rac)-Desfesoterodine), an active metabolite of Tolterodine, is a mAChR antagonist (Ki values of 2.3 nM, 2 nM, 2.5 nM, 2.8 nM, and 2.9 nM for M1, M2, M3, M4, and M5 receptors, respectively). (Rac)-5-Hydroxymethyl Tolterodine can be used for overactive bladder research[1].
In vitro, (Rac)-5-Hydroxymethyl Tolterodine (PNU-200577) produces a competitive and concentration-dependent inhibition of carbachol-induced contraction of guinea-pig isolated urinary bladder strips (KB of 0.84 nM; pA2 of 9.14)[2].
(Rac)-5-Hydroxymethyl Tolterodine (5-HMT; 0.88 μmol/kg; i.v.) treatment shows the binding activity of (Rac)-5-Hydroxymethyl Tolterodine to muscarinic receptors is significantly observed in all tissues, except cerebral cortex, with a longer duration in bladder[3].
[1]. L Nilvebrant, et al. Antimuscarinic potency and bladder selectivity of PNU-200577, a major metabolite of tolterodine. Pharmacol Toxicol. 1997 Oct;81(4):169-72.
[2]. B Malhotra, et al. The design and development of fesoterodine as a prodrug of 5-hydroxymethyl tolterodine (5-HMT), the active metabolite of tolterodine. Curr Med Chem. 2009;16(33):4481-9.
[3]. Shizuo Yamada, et al. Muscarinic receptor binding of fesoterodine, 5-hydroxymethyl tolterodine, and tolterodine in rat tissues after the oral, intravenous, or intravesical administration. J Pharmacol Sci. 2019 May;140(1):73-78.