title: Bioavailability of mifepristone in capsule versus tablet form in healthy nonpregnant women.
abstract: BACKGROUND
  The study was conducted to assess the bioavailability of two formulations of mifepristone in capsule and tablet forms at a single dose of 75 mg (half the registered dose in China).
  
  
  METHODS
  A randomized two-way crossover study was conducted in 18 healthy nonpregnant women. Each subject was orally given a single dose of mifepristone at 75 mg in capsule or tablet form on an alternate basis. Serial blood samples were collected over a period of 96 h and assayed for the plasma concentration of mifepristone by high-performance liquid chromatography. Paired t tests were used to compare the capsule and tablet forms in terms of maximum concentration (C(max)), time to maximum concentration (T(max)) and area under the curve over 96 h (AUC(0-96 h)). Relative bioavailability (capsule/tablet) was derived from AUC(0-96 h). Bioequivalability was analyzed by two one-sided t tests.
  
  
  RESULTS
  The major pharmacokinetic parameters were as follows: C(max) values were 1.26+/-0.38 and 1.25+/-0.40 mcg/mL, T(max) values were 0.94+/-0.34 and 0.89+/-0.47 h, T(1/2Ke) values were 36.2+/-21.0 and 33.4+/-12.3 h and AUC((0-96 h)) values were 19.7+/-6.4 and 19.6+/-9.9 mcg.h/mL for mifepristone in capsule and tablet forms, respectively. No significant difference was observed among these parameters. The relative bioavailability was 109.4+/-34.8%.
  
  
  CONCLUSIONS
  This study suggests that the two formulations of mifepristone are bioequivalent, which provides pharmacokinetic evidence for further reducing the dosage of mifepristone in clinical use.
authors.affiliation: Family Planning Research Institute, Center of Reproductive Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, PR China. aihualiao@hotmail.com
authors.forename: Aihua
authors.initials: A
authors.lastname: Liao
authors.forename: Xuebing
authors.initials: X
authors.lastname: Pang
authors.forename: Honggang
authors.initials: H
authors.lastname: Li
authors.forename: Zhongming
authors.initials: Z
authors.lastname: Xiong
authors.forename: Xirui
authors.initials: X
authors.lastname: Wu
mesh_terms: D000284:Administration, Oral; D000328:Adult; D001682:Biological Availability; D002214:Capsules; D002853:Chromatography, Liquid; D003283:Contraceptives, Postcoital, Synthetic / Q000008:administration & dosage* / Q000493:pharmacokinetics*; D018592:Cross-Over Studies; D005260:Female; D006801:Humans; D015735:Mifepristone / Q000008:administration & dosage* / Q000493:pharmacokinetics*; D013607:Tablets
chemical_list: D002214:Capsules; D003283:Contraceptives, Postcoital, Synthetic; D013607:Tablets; D015735:Mifepristone