YM022 is a highly potent, selective and orally active gastrin/cholecystokinin (CCK)-B receptor (CCK-BR) antagonist. YM022 shows the Ki values of 68 pM and 63 nM for CCK-B and CCK-A receptor, respectively. YM022 can inhibit gastrin-induced gastric acid secretion and histidine decarboxylase activation in vivo.IC50 & Target: Ki:68 pM (CCK-BR); 63 nM (CCK-AR)In Vitro: YM022 inhibits binding to canine pancreas CCK-A receptor in a dose-dependent manner, with an IC50 value for [3H]devazepide binding of 136 nM.YM022 inhibits the binding of [125I]CCK-8 to canine cloned gastrin/CCK-B receptor in a dose-dependent manner, with an IC50 value for [125I]CCK-8 binding of 0.73 nM.Selectivity [ratio of (IC50 for gastrin/CCK-B receptor)/(IC50for CCK-A receptor)] of YM022 is 186.In Vivo: YM022 (intravenous injection; 0.01-1 μM/kg) dose-dependently inhibits pentagastrin- and peptone meal-induced acid secretion with ED50 values of 0.0261 and 0.0654 μmol/kg, respectively, without affecting histamine- or methacholine-induced acid secretion.YM022 (subcutaneous injection; 300 μmol/kg; single dose) lowers the oxyntic mucosal HDC activity and raises the serum gastrin concentration in a dose-dependent manner (measured 24 h after dosage). Maximum enzyme inhibition is achieved at a dose of 300 μmol/kg ?for YM022 and the inhibition of HDC lasts for 4 weeks. At sacrifice, drug residues can be seen at the injection site for as long as 4 (YM022) weeks after injection in rat.YM022 is suspended in 2% Methocel for oral ingestion and in PEG300 for subcutaneous injection.