Acid inhibition effect of ilaprazole on Helicobacter pylori-negative healthy volunteers: An open randomized cross-over study

OBJECTIVE:  The aim of this study was to evaluate the effects and safety of different doses of ilaprazole on healthy volunteers without a Helicobacter pylori infection. METHODS:  A total of 12 healthy Chinese volunteers were enrolled and divided into four groups randomly, with a 5-day treatment of oral ilaprazole 5 mg, 10 mg and 20 mg or omeprazole 20 mg, respectively. After an interval of a 14-day washout phase, each was switched to another dose group and eventually completed all four regimens. The percentage time of intragastric pH > 4 was the major index. The polymorphisms of the metabolic enzyme CYP2C19 in these volunteers were also detected. RESULTS:  The percentage time of intragastric pH > 4 in the ilaprazole 5, 10 and 20 mg groups were 80.4%, 88.1% and 91.0%, respectively, during the first 24 h, compared to that of the 20 mg omeprazole group (76.6%, P > 0.05). Ilaprazole 20 mg provided a significant higher mean 24-h pH than that of the same dose of omeprazole both on Day 1 (7.78 vs 6.67, P < 0.01) and Day 5 (7.95 vs 7.44, P < 0.05). No CYP2C19-dependent difference or obvious adverse effect were found in any ilaprazole groups. CONCLUSION:  Low dose ilaprazole offers a gastric acid inhibition comparable to a routine dose of omeprazole, and further investigations in patients with acid-associated diseases are needed.