(R,R)-Palonosetron Hydrochloride,(R)-2-((R)-quinuclidin-3-yl)-2,3,3a,4,5,6-hexahydro-1H-benzo[de]isoquinolin-1-one hydrochloride,Serotonin 5-HT3 receptor antagonist used in the prevention and treatment of chemotherapy-induced nausea and vomiting (CINV). Antiemetic.,Palonosetron Impurity