The compound with CAS 161796-77-6 is the sodium salt of 6-methoxy-2-[(R)-[(4-methoxy-3,5-dimethyl-2-pyridinyl)methyl]sulfinyl]-1H-benzimidazole. This is the sodium salt form of Dexlansoprazole, which is the R-enantiomer of lansoprazole. Dexlansoprazole is a proton pump inhibitor (PPI) that acts by irreversibly inhibiting the H+/K+ ATPase enzyme in the gastric parietal cells, thereby suppressing gastric acid secretion. Dexlansoprazole sodium is the active pharmaceutical ingredient (API) used in the formulation of delayed-release capsules for the treatment of conditions such as gastroesophageal reflux disease (GERD), including erosive esophagitis and non-erosive reflux disease. Its dual delayed-release formulation is designed to provide a prolonged duration of acid suppression. As a chiral drug, the sodium salt is a key intermediate in the synthesis and final purification of the API. In addition to its primary use as an API, this specific sodium salt form is also relevant as a reference standard or impurity standard in pharmaceutical quality control and analytical method development for Dexlansoprazole-based drug products.