title: Once versus divided daily dosing with delayed-release mesalazine: a study of tissue drug concentrations and standard pharmacokinetic parameters.
abstract: BACKGROUND
  Delayed-release mesalazine is traditionally taken as three divided doses. However, it is well-recognized that dosing frequency has a significant impact on compliance and that once daily dosing is preferable.
  
  
  METHODS
  We measured serum, urinary, faecal and rectal tissue concentrations of 5-aminosalicylic acid and N-acetyl 5-aminosalicylic acid in 24 healthy volunteers following dosing with delayed-release mesalazine, 1.2 g or 2.4 g daily, given as either a single daily dose at 08:00 hours or in three divided doses at 08:00, 13:00 and 18:00 hours.
  
  
  RESULTS
  Urinary and faecal excretion and rectal tissue concentrations of 5-aminosalicylic acid and N-acetyl 5-aminosalicylic acid were similar following single or divided daily dosing, at both doses studied. Peak serum concentrations were found at 06:00-09:00 following divided dosing and at 17:00-20:00 following once daily dosing. However, peak and trough serum levels and serum area under curve values (AUC) were similar with both regimens and at both doses.
  
  
  CONCLUSIONS
  Urinary, faecal and rectal tissue concentrations are similar following single or divided daily dosing. Minor differences in serum levels were apparent but maximum, minimum and AUC values were similar. Clinical trials should examine the efficacy and toxicity of once daily dosing in patients with ulcerative colitis.
authors.affiliation: Department of Gastroenterology, Northern General Hospital, Sheffield, UK.
authors.forename: F N
authors.initials: FN
authors.lastname: Hussain
authors.forename: R A
authors.initials: RA
authors.lastname: Ajjan
authors.forename: K
authors.initials: K
authors.lastname: Kapur
authors.forename: M
authors.initials: M
authors.lastname: Moustafa
authors.forename: S A
authors.initials: SA
authors.lastname: Riley
mesh_terms: D000293:Adolescent; D000328:Adult; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000493:pharmacokinetics*; D003692:Delayed-Action Preparations; D004334:Drug Administration Schedule; D005260:Female; D006801:Humans; D008297:Male; D019804:Mesalamine / Q000008:administration & dosage / Q000493:pharmacokinetics*; D010349:Patient Compliance
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D003692:Delayed-Action Preparations; D019804:Mesalamine