VU 6008667 is a selective negative allosteric modulator of M5 NAM with IC50s of 1.2 μM and 1.6 μM for human M5 and rat M5, respectively. High CNS penetration.IC50 & Target: IC50: 1.2 μM (Human M5); 1.6 μM (Rat M5)In Vivo: VU 6008667 (1 mg/kg)/PO (3 mg/kg, solution dose) displays a diminished elimination half-life (t1/2=2.3 hr) driven by a smaller volume (Vss=7.4 L/kg) and higher clearance (CLp=82 mL/min/kg), with moderate oral bioavailability (17% F).