881681-00-1

TAK-438 (free base) is a novel P-CAB (potassium-competitive acid blocker) that reversibly inhibits H+/K+ ATPase with IC50 of 19 nM (pH 6.5), controls gastric acid secretion.IC50 value: 19 nM [1]Target: H+/K+ ATPasein vitro: TAK-438 is a pyrrole derivative with a chemical structure that is completely different from the P-CABs developed to date. TAK-438 inhibits gastric H+/K+ ATPase activity in a concentration-dependent manner. Under neutral conditions (pH 7.5), the inhibitory activity of TAK-438 is almost the same as that under weakly acidic conditions (pH 6.5). TAK-438 does not inhibit Na+/K+ ATPase activity even at concentration 500 times higher than their IC50 values against gastric H+/K+ ATPase activity. TAK-438 inhibits gastric H+/K+ ATPase in a K+ competitive manner with Ki of 3 nM [2]. in vivo: TAK-438 inhibits basal gastric acid secretion in a dose-dependent manner, and the ID50 value is 1.26 mg/kg. Intravenous administration of TAK-438 dose-dependently increases the pH of the gastric perfusate, and the increase in pH is sustained for 5 h after administration. At the 1 mg/kg dose, the pH plateaues 90 min after administration, and the highest pH value reached is 5.9 [2]. In addition, TAK-438 shows a potent and longer-lasting inhibitory effect on the histamine-stimulated gastric acid secretion in rats and dogs. TAK-438 shows significant antisecretory activity through high accumulation and slow clearance from the gastric tissue. TAK-438 is unaffected by the gastric secretory state, unlike PPIs [3].