[Pharmacokinetics of high-dosage naftopidil capsules in dogs].
OBJECTIVE
To establish a high-performance liquid chromatography (HPLC) for the determination of naftopidil in plasma, and make a study of pharmacokinetics of high-dose naftopidil capsules in dogs.


METHODS
Five healthy dogs were treated with naftopidil capsules in an oral single dose of 200 mg. Naftopidil in dog plasma was determined by HPLC. The mobile phase consisted of acetonitrile and 0.05 mol.L-1 phosphate buffer (pH 6.5) (60:40), verapamil was selected as internal standard, and the eluate was monitored at 230 nm. Pharmacokinetics calculations were carried out by practice pharmacokinetics programs (Version 97, 3P97).


RESULTS
The calibration curve of naftopidil was linear within the range of 10-1,200 ng.ml-1, and the correlation coefficient was 0.9992, the recovery rate of HPLC was (100.23 +/- 3.00)%, within day RSD and between day RSD were no more than 5.56% and 3.30% respectively. The plasma drug concentration-time course in dogs conformed to the one-compartment model. T1/2Ke value was (1.91-4.99) h, Tmax was (1.87-3.21) h, Cmax was (338.79-414.04) ng.ml-1.


CONCLUSIONS
HPLC is accurate and reliable, and can be used for studying the pharmacokinetics of high-dose naftopidil capsules in dogs.
Ding
J S
JS
Department of Pharmacy, Second Xinagya Hospital, Central South University, Changsha 410011, China.
Jiang
X H
XH
D000317:Adrenergic alpha-Antagonists / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics*; D000818:Animals; D002214:Capsules; D002851:Chromatography, High Pressure Liquid; D004285:Dogs; D009281:Naphthalenes / Q000097:blood / Q000493:pharmacokinetics*; D010879:Piperazines / Q000097:blood / Q000493:pharmacokinetics*
D000317:Adrenergic alpha-Antagonists; D002214:Capsules; D009281:Naphthalenes; D010879:Piperazines; C064357:naftopidil