Clozapine N-oxide-d8 is the deuterium labeled Clozapine N-oxide (HY-17366). Clozapine N-oxide is a major metabolite of Clozapine and a human muscarinic designer receptors (DREADDs) agonist. Clozapine N-oxide activates the DREADD receptor hM3Dq and hM4Di. Clozapine N-oxide cant cross the blood-brain barrier[1][2][3][4]. Clozapine is a potent dopamine antagonist and also a potent and selective muscarinic M4 receptor (EC50=11 nM) agonist[5][6].