ML218 is a selective T-type calcium channel inhibitor with IC₅₀s of 270 and 310 nM for Cav3.3 and Cav3.2 in electrophysiology assay, respectively. IC50 & Target: IC50: 270 nM (Ca_v3.3), 310 nM (Ca_v3.2)^[1] In Vitro: ML218 (CID 45115620) inhibits Cav3.1, Cav3.2, Cav3.3^[1]. In Vivo: Electrophysiology studies in STN neurons demonstrate robust effects of ML218 on the inhibition of T-type calcium current, inhibition of low threshold spike, and rebound burst activity. ML218 was found to be orally efficacious in a dose-dependent manner in a preclinical Parkinson’s disease model, haloperidol-induced catalepsy, and comparable to clinically validated A2A antagonism^[1]. ML218 reaches a peak cerebrospinal fluid concentration 1-2 hrs after s.c. administration. No effects of ML218 on cardiac rhythmicity is found in electrocardiographic studies. ML218 does not have antiparkinsonian effects in MPTP-treated parkinsonian monkeys, due at least in part, to the agent’s sedative effects^[2].