Naluzotan (PRX 00023)

Naluzotan is a novel, potent, and selective amidosulfonamide 5-HT1A agonist with IC50 and Ki of appr 20 nM and 5.1 nM, used for the treatment of anxiety and depression; Also a weak hERG K+ channel blocker, with IC50 of 3800 nM.

Naluzotan behaves as a full agonist in an in vitro cell-based functional assay with an EC50 of 20 nM. Naluzotan has significant affinity is the guinea pig sigma receptor (Ki = 100 nM), but does not inhibit cytochrome P450 isoforms (CYP) 1A2, 2C9, 2C19, 2D6, and 3A4[1].

In rats Naluzotan shows 11% oral bioavailability with a serum t1/2 of 2-3.5 h when administrated po, attaining a Cmax level of 24 ± 13 ng/mL (3 mg/kg, po). Naluzotan shows significant brain penetration, achieving a brain:serum concentration ratio of approximately 0.5 in the rat at 1 h following either intravenous or oral administration and reaching brain concentration approximately equivalent to that of buspirone. In dogs the pharmacokinetic profile of naluzotan shows 16% oral bioavailability, a serum t1/2 of 1.1 h po, and a Cmax level of 174 ± 141 ng/mL (3 mg/kg, po)[1]. PRX-00023 (0.01-0.05 mg/kg, i.p.) significantly reduces USV rates, but done of these doses produce sedation in rats[2].

[1]. Becker OM, et al. An integrated in silico 3D model-driven discovery of a novel, potent, and selective amidosulfonamide 5-HT1A agonist (PRX-00023) for the treatment of anxiety and depression. J Med Chem. 2006 Jun 1;49(11):3116-35. [2]. Brunelli SA, et al. PRX-00023, a selective serotonin 1A receptor agonist, reduces ultrasonic vocalizations in infant rats bred for high infantile anxiety. Pharmacol Biochem Behav. 2009 Nov;94(1):8-15.