title: Clinical trial: evaluation of gastric acid suppression with three doses of immediate-release esomeprazole in the fixed-dose combination of PN 400 (naproxen/esomeprazole magnesium) compared with naproxen 500 mg and enteric-coated esomeprazole 20 mg: a randomized, open-label, Phase I study in healthy volunteers.
abstract: BACKGROUND
  PN 400 is a fixed-dose combination formulated to provide sequential delivery of immediate-release (IR) esomeprazole and enteric-coated (EC) naproxen.
  
  
  OBJECTIVE
  To evaluate gastric acid suppression with three doses of esomeprazole in PN 400 compared with EC esomeprazole 20 mg.
  
  
  METHODS
  In this Phase I, randomized, open-label study, 28 healthy adults received PN 400 b.d. (naproxen 500 mg plus esomeprazole 10, 20 and 30 mg) and non-EC naproxen 500 mg b.d. plus EC esomeprazole 20 mg o.d., each for 9 days in a crossover fashion. The primary endpoint was percentage of time on day 9 that intragastric pH was >4.0; secondary endpoints included pharmacokinetics and safety.
  
  
  RESULTS
  Day 9 percentage of time where intragastric pH was >4.0 was 76.5%, 71.4%, 40.9% and 56.9% [corrected] for PN 400 containing 30, 20 and 10 mg esomeprazole, and naproxen plus esomeprazole 20 mg respectively. This was significantly greater for PN 400 containing 30 and 20 mg esomeprazole vs. naproxen plus esomeprazole 20 mg (95% CI: 13.0-26.0 and 7.8-20.7 respectively). The pharmacokinetics of PN 400 were consistent with its formulation. No serious adverse events occurred.
  
  
  CONCLUSIONS
  PN 400 containing 20 mg esomeprazole was the lowest dose to achieve gastric acid suppression comparable to EC esomeprazole 20 mg and was selected for further evaluation.
authors.affiliation: Oklahoma Foundation for Digestive Research, Oklahoma City, 73104, USA. philip-miner@ouhsc.edu
authors.forename: P
authors.initials: P
authors.lastname: Miner
authors.forename: J
authors.initials: J
authors.lastname: Plachetka
authors.forename: E
authors.initials: E
authors.lastname: Orlemans
authors.forename: J G
authors.initials: JG
authors.lastname: Fort
authors.forename: M
authors.initials: M
authors.lastname: Sostek
mesh_terms: D000293:Adolescent; D000328:Adult; D000897:Anti-Ulcer Agents / Q000493:pharmacokinetics / Q000627:therapeutic use*; D017321:Clinical Trials, Phase I as Topic; D018592:Cross-Over Studies; D004305:Dose-Response Relationship, Drug; D004334:Drug Administration Schedule; D064098:Esomeprazole / Q000493:pharmacokinetics / Q000627:therapeutic use*; D005260:Female; D005744:Gastric Acid / Q000378:metabolism*; D006801:Humans; D008274:Magnesium / Q000493:pharmacokinetics / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D009288:Naproxen / Q000493:pharmacokinetics / Q000627:therapeutic use*; D055815:Young Adult
chemical_list: D000897:Anti-Ulcer Agents; D009288:Naproxen; D008274:Magnesium; D064098:Esomeprazole