title: Quantitative analysis of valsartan by two-dimensional liquid chromatography (2D-HPLC) and its application in a bioequivalence study in Chinese volunteers .
abstract: OBJECTIVE
  To develop a sensitive, two-dimensional liquid chromatography (2D-LC) method for determination of valsartan, applied to investigate bioequivalence of two valsartan tablets in Chinese volunteers under fasting condition.
  
  
  METHODS
  A full automatic 2D-HPLC system was used to quantify valsartan in human plasma. The analytes were extracted by protein precipitation, using telmisartan as internal standard. The analytical method was applied in a randomized, crossover bioequivalence study of valsartan tablets; the study enrolled 18 Chinese volunteers (12 were men and 6 were women). The subjects received a single 160-mg dose of test or reference preparation with 7-days of washout under fasting state. Plasma samples were collected, pharmacokinetic parameters were obtained and the bioequivalence was evaluated.
  
  
  RESULTS
  The calibration range was 9.2 - 4213.8 ng×mL-1. Inter- and intraprecision was less than 7.0%, and accuracies ranged from 99.5 to 103.8%. The extraction recovery for valsartan varied between 89.3 and 97.8%, and the stability in all conditions was excellent. The 90% CI of AUC0→36hand Cmaxwere 96.5 - 109.4% and 94.2 - 108.6%, respectively. The relative bioavailability was 103.9 ± 15.7%. No gender difference was observed in pharmacokinetic parameters.
  
  
  CONCLUSIONS
  A sensitive 2D-HPLC method was established for the estimation of valsartan in human plasma and successfully applied in a bioequivalence study of valsartan, which suggests that these two formulations can be assumed to be bioequivalent. .
authors.forename: Min
authors.initials: M
authors.lastname: Zhang
authors.forename: Yang
authors.initials: Y
authors.lastname: Deng
authors.forename: Hua-Lin
authors.initials: HL
authors.lastname: Cai
authors.forename: Ping-Fei
authors.initials: PF
authors.lastname: Fang
authors.forename: Miao
authors.initials: M
authors.lastname: Yan
authors.forename: Bi-Kui
authors.initials: BK
authors.lastname: Zhang
authors.forename: Yan-Qin
authors.initials: YQ
authors.lastname: Wu
mesh_terms: D000284:Administration, Oral; D000328:Adult; D047228:Angiotensin II Type 1 Receptor Blockers / Q000008:administration & dosage / Q000009:adverse effects / Q000097:blood / Q000493:pharmacokinetics*; D019540:Area Under Curve; D044466:Asian People; D002138:Calibration; D002681:China; D002851:Chromatography, High Pressure Liquid / Q000379:methods* / Q000592:standards; D018592:Cross-Over Studies; D005260:Female; D064368:Healthy Volunteers; D006801:Humans; D008297:Male; D008657:Metabolic Clearance Rate; D012015:Reference Standards; D015203:Reproducibility of Results; D013607:Tablets; D013810:Therapeutic Equivalency; D000068756:Valsartan / Q000008:administration & dosage / Q000009:adverse effects / Q000097:blood / Q000493:pharmacokinetics*; D055815:Young Adult
chemical_list: D047228:Angiotensin II Type 1 Receptor Blockers; D013607:Tablets; D000068756:Valsartan