title: Pharmacokinetic profile of extended-release versus immediate-release oral naproxen sodium after single and multiple dosing under fed and fasting conditions: two randomized, open-label trials.
abstract: OBJECTIVE
  Extended-release (ER) naproxen sodium provides pain relief for up to 24 hours with a single dose (660 mg/day). Its pharmacokinetic profile after single and multiple dosing was compared to immediate release (IR) naproxen sodium in two randomized, open-label, crossover studies, under fasting and fed conditions.
  
  
  METHODS
  Eligible healthy subjects were randomized to ER naproxen sodium 660-mg tablet once daily or IR naproxen sodium 220-mg tablet twice daily (440 mg initially, followed by 220 mg 12 hours later). Primary variables: pharmacokinetic parameters after singleday administration (day 1) and at steady state after multiple-day administration (day 6).
  
  
  RESULTS
  Total exposure was comparable for both treatments under fasting and fed conditions. After fasting: peak naproxen concentrations were slightly lower with ER naproxen sodium than with IR naproxen sodium but were reached at a similar time. Fed conditions: mean peak concentrations were comparable but reached after a longer time with ER vs. IR naproxen sodium. ER naproxen sodium was well tolerated, with a similar safety profile to IR naproxen sodium.
  
  
  CONCLUSIONS
  The total exposure of ER naproxen sodium (660 mg) is comparable to IR naproxen sodium (220 mg) when administered at the maximum over the counter (OTC) dose of 660-mg daily dose on a single day and over multiple days. The rate of absorption is delayed under fed conditions.
authors.affiliation: Bayer Consumer Health, Whippany, NJ and Bayer HealthCare Pharmaceuticals, Whippany, NJ, USA.
authors.forename: Irene
authors.initials: I
authors.lastname: Laurora
authors.forename: Yuan
authors.initials: Y
authors.lastname: Wang
mesh_terms: D000284:Administration, Oral; D000328:Adult; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000008:administration & dosage* / Q000009:adverse effects / Q000493:pharmacokinetics; D018592:Cross-Over Studies; D003692:Delayed-Action Preparations; D065546:Drug Liberation; D005215:Fasting; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009288:Naproxen / Q000008:administration & dosage* / Q000009:adverse effects / Q000493:pharmacokinetics; D013607:Tablets; D055815:Young Adult
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D003692:Delayed-Action Preparations; D013607:Tablets; D009288:Naproxen