AF-353 hydrochloride

This novel compound is an orally bioavailable antagonist of P2X3/P2X2/3 receptors, exhibiting potent activity with a pIC50 of 8 in both human and rat, and a pIC50 of 7.3 specifically for the human P2X2/3 receptor. It demonstrates high brain penetration, evidenced by a brain to plasma ratio of 6, and effectively blocks agonist-evoked intracellular Ca2+ flux and inward currents within the nanomolar range (10 nM to 1 µM) in cell lines that express human P2X3 and P2X2/3 receptors recombinantly. The compound also shows favorable pharmacokinetic properties, with a half-life (t1/2) of 1.63 hours and a time to reach maximum concentration (Tmax) of 30 minutes.