Pharmacodynamics and kinetics of omeprazole MUPS 20 mg and pantoprazole 40 mg during repeated oral administration in Helicobacter pylori-negative subjects

BACKGROUND: Omeprazole has become available in a tablet formulation, a Multiple Unit Pellet System (MUPS) containing a large number of small individually enteric-coated micropellets. AIM: To compare the acid-inhibitory effect of omeprazole MUPS 20 mg with pantoprazole 40 mg and to describe the pharmacokinetics of both drugs following administration on day 1 and day 6. METHODS: Randomized, two-way crossover study. Sixteen Helicobacter pylori-negative healthy subjects, whose gastric acidity fell below pH 4 for 70% of a 24-h baseline period were included. Intragastric pH was measured continuously. RESULTS: On day 1 both drugs significantly raised median 24-h gastric pH compared to baseline. Median pH and percentages of time above pH 3 and 4 on day 1 and day 6 of administration were not significantly different, with the exception of median daytime pH on day 6, which was significantly higher with omeprazole (4.65 vs. 4.05). AUC and Cmax of omeprazole were significantly increased on day 6. AUC and Cmax of pantoprazole were not significantly increased. CONCLUSIONS: No significant difference in acid-inhibitory effect on day 1. On day 6 median daytime pH was significantly higher with omeprazole MUPS, but the percentages of time spent above pH 3 and 4 were not significantly different. The significant increase in bioavailability of omeprazole may contribute to the increased effect on day 6.