title: Bioequivalence study of two brands of enalapril tablets after single oral administration to healthy volunteers.
abstract: OBJECTIVE
  To compare the relative bioavailability and bioequivalence of 2 enalapril tablet formulations in healthy volunteers under fasting conditions.
  
  
  METHODS
  An open-label, single-dose, randomized, two-period, crossover trial with a 1-week washout period in 24 healthy volunteers. The 2 enalapril 20 mg tablet formulations used were Antiprex (Elpen, Greece) as test and Renitec (Vianex, Greece) as reference preparation. Serial blood samples were collected at 19 points for 36 h. Plasma samples were analyzed for enalaprilat, the pharmacologically active metabolite of enalapril, by a validated GC/MS assay. Pharmacokinetic parameters, such as AUC(0-infinity), AUC(0-t), C(max) T(max), t1/2 and MRT were calculated from plasma concentrations for both formulations. Statistical comparisons (ANOVA and 90% confidence intervals) of AUC(0-infinity), AUC(0-t) and C(max) data were evaluated after logarithmic transformation, and differences of T(max) were tested non-parametrically.
  
  
  RESULTS
  The parametric 90% confidence intervals of the geometric mean values of the test/reference ratios were 88.0 - 117.6% (point estimate: 101.8%) for AUC(0-infinity), 88.7 - 118.9% (point estimate: 102.7%) for AUC(0-t), and 91.0% - 123.4% (point estimate: 106.0%) for C(max) No statistically significant differences were found between the 2 preparations for T(max) t1/2 and MRT values.
  
  
  CONCLUSIONS
  From the results of the present study, it is concluded that the test and reference tablet formulations of enalapril are bioequivalent for both the extent and the rate of absorption and therefore the 2 products can be considered to be interchangeable in clinical practice.
authors.affiliation: Department of Pharmacy, School of Health Sciences, Aristotle University of Thessaloniki, Greece. niopas@pharm.auth.gr
authors.forename: I
authors.initials: I
authors.lastname: Niopas
authors.forename: A C
authors.initials: AC
authors.lastname: Daftsios
authors.forename: N
authors.initials: N
authors.lastname: Nikolaidis
mesh_terms: D000284:Administration, Oral; D000328:Adult; D000704:Analysis of Variance; D019540:Area Under Curve; D018592:Cross-Over Studies; D004656:Enalapril / Q000097:blood / Q000493:pharmacokinetics*; D015773:Enalaprilat / Q000097:blood; D005260:Female; D008401:Gas Chromatography-Mass Spectrometry; D006207:Half-Life; D006801:Humans; D008297:Male; D013607:Tablets; D013810:Therapeutic Equivalency; D013997:Time Factors
chemical_list: D013607:Tablets; D004656:Enalapril; D015773:Enalaprilat