Group 1: This group was randomized into a 2-way crossover design with an added third period. These participants received single administrations (day 1 dosing only) of Zegerid Powder for Oral Suspension, and Prilosec OTC (both at a 20 mg omeprazole dose), in a 2-way randomized order, with a minimum of a 2-week washout period between treatment legs. Following completion of the 2-way crossover study, and a subsequent washout period (minimum of 2 weeks), all participants then received a single administration of sodium bicarbonate (at same dose as contained in Zegerid Powder for Oral Suspension) in Period 3. This group underwent a 24-hour intragastric pH study on each of the 3 dosing occasions.