All subjects will be confined at the Clinical Research Unit the day prior to the omeprazole administration on Day 7 and will remain confined for approximately 13 hours following the dosing on Day 8. Blood samples for determination of plasma omeprazole concentrations will be obtained from all subjects at 0 (10 minutes pre-dose), 20, 40 minutes and 1, 1.5, 2, 2.5, 3, 4, 6, 8, 10 and 12 hours post-dose on Days 7 and 8. Pre-dose blood samples for determination of omeprazole will also be taken in the morning on Days 5-6.