Perospirone-d8 (SM-9018-d8 (free base)) is deuterium labeled Perospirone. Perospirone (SM-9018 free base) is an orally active antagonist of 5-HT2A receptor (Ki=0.6 nM) and dopamine D2 receptor (Ki=1.4 nM), and also a partial agonist of 5-HT1A receptor (Ki=2.9 nM). Perospirone is an atypical antipsychotic agent and has the potential for schizophrenic disease research[1][2][3].