• The primary efficacy variable is the percentage of time intragastric pH >4 for the 24-hour monitoring period on Day 1 (i.e.: first day of dosing for each treatment period).
  

• Percentage of time intragastric pH is >3, >4, >5, >6 on Day 1, and on Day 3 over time intervals: 0-14h and 14-24h after dosing;Median intragastric pH on Day 1 and Day 3 (entire 24-hour interval, and over time intervals: 0-14h and 14-24h after dosing)
  

Following screening to determine eligibility (normal medical history, physical examination including vital signs, laboratory findings, negative test for active H. pylori infection, and a negative pregnancy test if applicable) and subsequent enrolment, patients will have a baseline 24-hour intragastric pH recording. Patients will receive either oral rabeprazole 20mg or intravenous pantoprazole 40mg daily for 3 consecutive days. For blinding purposes, patients will also receive either a placebo oral tablet or placebo intravenous solution ("double-dummy" design). A 24-hour intragastric pH recording will be completed on Day 1 and Day 3 of the drug administration period. This will be followed by a 14-day washout period before the second 3-day drug administration period during which the patient will receive the crossover drug regimen, and will again have 24-hour intragastric pH recordings completed on the first and third days of this second drug administration period.Thirty-seven patients with a negative test for active H. pylori infection test will be randomised into the study. The primary hypothesis is that oral rabeprazole produces equivalent acid suppression to intravenous pantoprazole as indicated by the time during which intragastric pH is greater than 4 on Day 1 of drug administration.

Eligible patients will be randomly assigned to 1 of the 2 treatment groups and will first receive either oral rabeprazole 20mg plus placebo intravenous solution or intravenous pantoprazole 40mg plus a placebo oral tablet daily for 3 consecutive days. After a 14-day washout, patients will receive the crossover drug regimen. Rabeprazole: supplied as 20mg tablets (and matching placebo tablets). Pantoprazole: supplied as 12-mL vials of lyophilized powder containing pantoprazole 40mg (pantoprazole