Clozapine-d₄ contains four deuterium atoms on the piperazinyl ring. It is intended for use as an internal standard for the quantification of clozapine (Item No. 12059) by GC- or LC-mass spectrometry. Clozapine is a partial agonist at the 5-HT_1A receptor (pK_i = 7) and interferes to a lesser extent with the binding of dopamine at D₁, D₂, D₃, and D₅ receptors, yet has a high affinity for the D₄ receptor.¹ It is also a strong antagonist at different subtypes of adrenergic, cholinergic, and histaminergic receptors. Clozapine induces the release of glutamate and D-serine, an agonist at the glycine site of the NMDA receptor, from astrocytes, and reduces the expression of astrocytic glutamate transporters.²

≥99% deuterated forms (d₁-d₄)