[Studies on in-vivo process of the enantiomers of nicardipine in rabbit by coupled chiral and achiral HPLC].
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.
Wang
S C
SC
College of Pharmacy, Xi'an Jiaotong University, Xi'an 710061, China.
He
L C
LC
Liu
F
F
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
D002121:Calcium Channel Blockers; D009529:Nicardipine