This will be a randomized, open-label, single-center, 3-way crossover study in healthy subjects who are confirmed to be Helicobacter pylori (H. pylori)-negative. The study will consist of 3 study periods separated by a washout period of at least 7 days. Subjects will receive study drugs once daily for 5 days. Barring any safety concerns, subjects will be discharged from the study on Day 6 of Period 3 after completion of discharge procedures.

Key inclusion:

• Healthy male and female subjects, including women of child-bearing potential, aged 18 to 55 years, inclusive
• Subjects who are able to tolerate the insertion and placement of a pH probe on 2 occasions per study period (Day -1 and Day 5)

Key Exclusion:

• Subjects who are H. pylori-positive
• Subjects who have a history of any gastrointestinal disorder or surgery likely to influence drug absorption (e.g., history of gastric resection)
• Known hypersensitivity to rabeprazole, esomeprazole, or related compounds or any ingredient in the formulations
• Other standard clinical pharmacology exclusion criteria for healthy volunteers