title: Pharmacokinetics and bioequivalence of single dose and multiple doses of immediate- and extended-release formulations of dexibuprofen in healthy Chinese subjects.
abstract: OBJECTIVE
  To compare the pharmacokinetic (PK) profiles and bioequivalence of the extended-release (ER) and immediate-release (IR) formulations of dexibuprofen (DI) in healthy Chinese volunteers after single dose and multiple doses.
  
  
  METHODS
  Zefen® (IR capsule, containing 150 mg DI, Suzhou No.4 Pharmaceutical Factory, Jiangsu, China) and ER capsule (containing 225 mg DI, Tianjin Zhongtian Pharmaceutical Co. Ltd., Tianjin, China).
  
  
  METHODS
  This was an open, randomized, two-period crossover study. Eligible subjects were healthy male Chinese volunteers. 22 subjects were randomly assigned to receive a single 450 mg dose of the test or reference formulation on the first day. During the next 6 days, the test group received a multiple-dose of ER DI capsule (450 mg, b.i.d.) and the reference group took a multiple-dose of IR DI capsule (300 mg, t.i.d.), respectively. Multiple blood samples were collected, and plasma concentrations of DI were analyzed using high performance liquid chromatography (HPLC) system. After a 9-day washout period, the subjects were administered the alternate formulation. Bioequivalence was concluded if the 90% confidence interval (CI) for the ratio between test and reference was within accepted limits. Adverse events (AEs) were monitored and documented throughout the confinement in the clinic and washout phases of each study period.
  
  
  RESULTS
  21 subjects completed the single dose administration and 20 subjects were evaluable for the multiple doses PK parameters. Single-dose Mean AUC0-t and AUC0-inf for ER formulation were 116.14 ± 21.54 mg·h/l and 117.60 ± 22.27 mg·h/l, and for IR formulation, were 107.25 ± 23.48 mg·h/l and 108.18 ± 23.93 mg·h/l, with the 90% CI within the limits accepted for bioequivalence. Mean Cmax for ER and IR formulations were 22.30 ± 5.17 mg/l and 30.26 ± 13.54 mg/l, respectively. And median tmax for ER and IR formulations were 4.5 h and 2.0 h. The retard quotient (delta R) for ER product was 1.9 ± 0.93, which indicated an intermediate extended release effect. Multiple-dose Mean AUC0-24 for ER formulation was 217.93 ± 41.07 mg·h/l and for IR formulation was 199.33 ± 37.32 mg·h/l. Other PK parameters of ER and IR formulations were as follows: median tmax were 4.8 h and 2.0 h, Css-max were 20.21 ± 2.69 mg/l and 19.71 ± 3.46 mg/l, Css-min were 2.47 ± 0.99 mg/l and 2.48 ± 0.99 mg/l, Cav were 9.08 ± 1.71 mg/l and 8.31 ± 1.56 mg/l, respectively.
  
  
  CONCLUSIONS
  This study found that in these subjects, the absorption rates of the two DI formulations were not bioequivalent, but at steady state, the daily exposure provided by less frequent DI ER dosing was not significantly different from the same daily dose with DI IR capsules, administered more frequently.
authors.affiliation: Department of Clinical Pharmacology, Affiliated Hospital of Nanjing University of Traditional Chinese Medicine, Nanjing, China.
authors.forename: M J
authors.initials: MJ
authors.lastname: Xu
authors.forename: C
authors.initials: C
authors.lastname: Zou
authors.forename: J
authors.initials: J
authors.lastname: H Chu
authors.forename: T
authors.initials: T
authors.lastname: Wu
authors.forename: S J
authors.initials: SJ
authors.lastname: Liu
authors.forename: J
authors.initials: J
authors.lastname: Zhang
authors.forename: M
authors.initials: M
authors.lastname: Chen
authors.forename: F
authors.initials: F
authors.lastname: Liu
authors.forename: N N
authors.initials: NN
authors.lastname: Xiong
authors.forename: W Z
authors.initials: WZ
authors.lastname: Ju
authors.forename: H
authors.initials: H
authors.lastname: S Tan
mesh_terms: D000328:Adult; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000008:administration & dosage / Q000009:adverse effects / Q000493:pharmacokinetics*; D019540:Area Under Curve; D002681:China; D002851:Chromatography, High Pressure Liquid; D018592:Cross-Over Studies; D003692:Delayed-Action Preparations; D004334:Drug Administration Schedule; D006801:Humans; D007052:Ibuprofen / Q000008:administration & dosage / Q000009:adverse effects / Q000031:analogs & derivatives* / Q000493:pharmacokinetics; D008297:Male; D013810:Therapeutic Equivalency; D055815:Young Adult
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D003692:Delayed-Action Preparations; C539402:dexibuprofen; D007052:Ibuprofen