title: Comparison of the effect of a single dose of omeprazole or lansoprazole on intragastric pH in Japanese participants: a two-way crossover study.
abstract: BACKGROUND
  It is known that the pharmacokinetic profile of proton pump inhibitors (PPIs) after postprandial administration may differ among PPIs. The purpose of this study was to compare the inhibitory effects of gastric acid secretion by PPIs administered after a meal, based on a 24-hour intragastric pH monitoring.
  
  
  METHODS
  Ten healthy men who provided written informed consent participated in the study. They were given a 20-mg omeprazole tablet and a 30-mg lansoprazole orally dispersing tablet in a two-way crossover manner. At baseline, the anti-HP-IgG antibody levels in blood and the pepsinogen (PG) I/II ratio were measured. Participants were given a standardized meal and 200 mL of water at 9:30 am, 13:30 pm, and 18.30 pm. Participants took the PPI after breakfast.
  
  
  RESULTS
  Two of the ten participants tested positive for Helicobacter pylori infection. The PG I/II ratio indicated negative gastric atrophy in all the participants. The percentage 24-hour intragastric pH > 4 holding times (median, range) with omeprazole and lansoprazole were 29.3, 19.3-50.0% and 27.8, 13.0-42.3%, respectively, which shows that with the administration of omeprazole, the pH was maintained at >4 for a longer period (p < 0.05). Each median intragastric pH value per hour at 3, 17, and 18 hours after a dose of omeprazole was significantly higher than that of lansoprazole (p < 0.05).
  
  
  CONCLUSIONS
  Compared with lansoprazole, a single postprandial dose of omeprazole showed a more rapid and sustained acid-inhibitory effect.
authors.affiliation: Department of Gastroenterology, Aichi Medical University, School of Medicine, Aichi, Japan. momomaru@aichi-med-u.ac.jp
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Funaki
authors.forename: Kentaro
authors.initials: K
authors.lastname: Tokudome
authors.forename: Shinya
authors.initials: S
authors.lastname: Izawa
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Tamura
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Kondo
authors.forename: Akihito
authors.initials: A
authors.lastname: Iida
authors.forename: Mari
authors.initials: M
authors.lastname: Mizuno
authors.forename: Naotaka
authors.initials: N
authors.lastname: Ogasawara
authors.forename: Makoto
authors.initials: M
authors.lastname: Sasaki
authors.forename: Kunio
authors.initials: K
authors.lastname: Kasugai
mesh_terms: D000328:Adult; D018592:Cross-Over Studies; D005745:Gastric Acidity Determination; D005753:Gastric Mucosa / Q000187:drug effects* / Q000378:metabolism; D006801:Humans; D006863:Hydrogen-Ion Concentration; D064747:Lansoprazole / Q000494:pharmacology*; D008297:Male; D009853:Omeprazole / Q000494:pharmacology*; D011446:Prospective Studies; D054328:Proton Pump Inhibitors / Q000494:pharmacology*
chemical_list: D054328:Proton Pump Inhibitors; D064747:Lansoprazole; D009853:Omeprazole