title: Pharmacokinetics of doxazosin gastrointestinal therapeutic system after multiple administration in Korean healthy volunteers.
abstract: Doxazosin mesylate is a selective alpha-adrenoreceptor antagonist for the treatment of hypertension and benign prostatic hyperplasia. A simple high performance liquid chromatographic method has been developed and validated for the quantitative determination of doxazosin in plasma. A reversed phase C18 column was used for the separation of doxazosin and prazosin (internal standard) with a mobile phase composed of water, acetonitrile, triethylamine (68:32:0.2 v/v, pH 5.0) at a flow rate of 1.2 mL/min. The fluorescence detector was operated at 246 (excitation) and 389 nm (emission). Intra- and inter-day precision and accuracy were acceptable for all quality control samples including the lower limit of quantification of 1 ng/mL. Recovery of doxazosin from human plasma was greater than 93.4%. Doxazosin was stable in human plasma under various storage conditions. This method was used successfully for a pharmacokinetic study in plasma after oral administration of multiple 4-mg dose of doxazosin gastrointestinal therapeutic system formulation to 16 healthy volunteers. At steady state the mean area under the curve for a dosing interval and elimination half-life were calculated to be 367.0 +/- 63.5 ng x hr/mL and 29.2 +/- 4.5 hr, respectively. There was no difference in pharmacokinetic parameters between male and female.
authors.affiliation: College of Pharmacy, Ewha Womans University, 11-1 Daehyun-Dong, Seodaemun-Gu, Seoul, South Korea.
authors.forename: Yoon Hee
authors.initials: YH
authors.lastname: Kwon
authors.forename: Hye Sun
authors.initials: HS
authors.lastname: Gwak
authors.forename: Sun Jung
authors.initials: SJ
authors.lastname: Yoon
authors.forename: In Koo
authors.initials: IK
authors.lastname: Chun
mesh_terms: D000317:Adrenergic alpha-Antagonists / Q000008:administration & dosage* / Q000097:blood / Q000493:pharmacokinetics*; D000328:Adult; D019540:Area Under Curve; D044466:Asian People; D002851:Chromatography, High Pressure Liquid; D003692:Delayed-Action Preparations; D017292:Doxazosin / Q000008:administration & dosage* / Q000097:blood / Q000493:pharmacokinetics*; D005260:Female; D006207:Half-Life; D006801:Humans; D007723:Korea; D008297:Male; D012737:Sex Factors
chemical_list: D000317:Adrenergic alpha-Antagonists; D003692:Delayed-Action Preparations; D017292:Doxazosin