title: [Studies on in-vivo process of the enantiomers of nicardipine in rabbit by coupled chiral and achiral HPLC].
abstract: OBJECTIVE
  To study the differences of the pharmacokinetics and tissue distribution of two enantiomers of nicardipine in the rabbit.
  
  
  METHODS
  Biological samples were diluted by 1 mol.L-1 NaOH solution and extracted with n-hexane--ethyl acetate (1:1). The concentrations of S-nicardipine and R-nicardipine in samples were determined by coupled achiral C18 column (150 mm x 4.6 mm, 5 microns) and chiral OJ column (250 mm x 4.6 mm, 10 microns) chromatography.
  
  
  RESULTS
  The racemic nicardipine and the enantiomers in sample were separated well by the coupled system. The linear range was 55-550 ng.mL-1 for both enantiomers. The within-day and between-days RSD (n = 5) were 5.25% and 8.97%, and the relative recoveries were 99.99% and 97.10% for R- and S-enantiomer, respectively. The mean Tmax, Cmax and AUC values were (2.49 +/- 0.03) h, (134 +/- 2) ng.mL-1 and (1082 +/- 32) ng.mL-1.h for S-nicardipine and (1.24 +/- 0.05) h, (109 +/- 2) ng.mL-1 and (778 +/- 22) ng.mL-1.h for R-nicardipine. The concentration of S-nicardipine were generally higher than that of R-nicardipine in main target tissues and cells.
  
  
  CONCLUSIONS
  There were significant differences between the two enantiomers of nicardipine in rabbit in pharmacokinetics and tissue distribution.
authors.affiliation: College of Pharmacy, Xi'an Jiaotong University, Xi'an 710061, China.
authors.forename: S C
authors.initials: SC
authors.lastname: Wang
authors.forename: L C
authors.initials: LC
authors.lastname: He
authors.forename: F
authors.initials: F
authors.lastname: Liu
mesh_terms: D000818:Animals; D002121:Calcium Channel Blockers / Q000737:chemistry / Q000493:pharmacokinetics*; D005260:Female; D008297:Male; D009529:Nicardipine / Q000737:chemistry / Q000493:pharmacokinetics*; D011817:Rabbits; D013237:Stereoisomerism; D014018:Tissue Distribution
chemical_list: D002121:Calcium Channel Blockers; D009529:Nicardipine