title: Pharmacokinetics and bioequivalence testing of generic ondansetron preparations in healthy Thai male volunteers.
abstract: METHODS
  Pharmacokinetics and bioequivalence of oral preparations of generic ondansetron were investigated in healthy Thai males. The test preparations were Vomitron 8 and Vomitron 4, the reference was Zofran. The three products were administered as an 8 mg single oral dose, in a three-period four-sequence cross-over design with one-week washout period. An intravenous 8 mg Zofran was administered on the forth visit. Plasma ondansetron concentrations were determined by HPLC and the pharmacokinetic parameters were analyzed by non-compartmental analysis.
  
  
  RESULTS
  Following i.v. ondansetron, the mean values of its elimination half-life, its plasma clearance, and its volume of distribution were 4.5 hours, 398 ml/min, and 130 liters, respectively. Its oral bioavailability averaged 67%, and the elimination half-life after oral administration was 5.6 hours. The time to reach the maximal concentration (Tmax, hour) of Zofran (1.21 +/- 0.26) was statistically faster than that of Vomitron 8 (1.33 +/- 0.54) and Vomitron 4 (1.46 +/- 0.50). The 90% confidence intervals of the AUC0-infinity and Cmax ratios muT/muR for (Vomitron 8/Zofran) were 0.88 - 1.12 and 0. 85 - 1.08, respectively. Similarly the 90% CI of the-AUC0-infinity and Cmax ratios for (Vomitron 4/Zofran) were 0.96 - 1.17 and 1.01 - 1.19, respectively.
  
  
  CONCLUSIONS
  These values were within the acceptable range of 0.80 - 1.25, thus our study demonstrated the bioequivalence of Vomitron and Zofran with respect to the rate (Cmax) and extent of absorption (AUC0-infinity).
authors.affiliation: Department of Pharmacology, Faculty of Medicine, Chiang Mai University, Thailand.
authors.forename: N
authors.initials: N
authors.lastname: Rojanasthien
authors.forename: M
authors.initials: M
authors.lastname: Manorot
authors.forename: B
authors.initials: B
authors.lastname: Kumsorn
mesh_terms: D000293:Adolescent; D000328:Adult; D000932:Antiemetics / Q000097:blood / Q000493:pharmacokinetics*; D019540:Area Under Curve; D001682:Biological Availability; D002851:Chromatography, High Pressure Liquid; D018592:Cross-Over Studies; D016568:Drugs, Generic / Q000493:pharmacokinetics*; D006207:Half-Life; D006801:Humans; D008297:Male; D017294:Ondansetron / Q000097:blood / Q000493:pharmacokinetics*; D013785:Thailand; D013810:Therapeutic Equivalency
chemical_list: D000932:Antiemetics; D016568:Drugs, Generic; D017294:Ondansetron