QNZ46 is a highly selective noncompetitive NMDA receptor antagonist targeting GluN2C/D (IC50=3.9 µM), GluN1/GluN2C (IC50=7.1 µM), and GluN1/GluN2D (IC50=182 µM) subunits. QNZ46 inhibits glutamate-mediated calcium influx, thereby blocking excitotoxicity. QNZ46 is membrane permeable and can cross the blood-brain barrier, where it inhibits myelin damage and axonal degeneration[1][2][3].