In vitro activity: Palonosetron is a highly potent, selective, second-generation 5-HT3 receptor antagonist with a 5-HT3 receptor binding affinity that is ~100-fold higher than other 5-HT3 receptor antagonists (pKi 10.5 compared with 8.91 for granisetron, 8.81 for tropisetron, 8.39 for ondansetron, 7.6 for dolasetron). Palonosetron also has an extended plasma elimination half-life of ~40 h, significantly longer than others in its class (ondansetron, 4 h; tropisetron, 7.3 h; dolasetron, 7.5 h; ranisetron, 8.9 h).

Kinase Assay: Palonosetron is a highly potent, selective, second-generation 5-HT3 receptor antagonist with a 5-HT3 receptor binding affinity that is ~100-fold higher than other 5-HT3 receptor antagonists (pKi 10.5 compared with 8.91 for granisetron, 8.81 for tropisetron, 8.39 for ondansetron, 7.6 for dolasetron).

Cell Assay: Palonosetron is a 5-HT3 antagonist used in the prevention and treatment of chemotherapy-induced nausea and vomiting (CINV). IC50 Value: Target: 5-HT3 Receptor Palonosetron is the most effective of the 5-HT3 antagonists in controlling delayed CINV nausea and vomiting that appear more than 24 hours after the first dose of a course of chemotherapy.