title: A simple, sensitive high-performance liquid chromatography -ultraviolet method for the quantification of concentration and steady-state pharmacokinetics of itraconazole and hydroxyitraconazole.
abstract: BACKGROUND
  A steady-state trough plasma itraconazole concentration greater than 500 ng/mL is a therapeutic target for itraconazole. A simple, rapid and sensitive high-performance liquid chromatography-based method was developed for quantitation of itraconazole and hydroxyitraconazole in human plasma.
  
  
  METHODS
  Itraconazole and hydroxyitraconazole were separated using a mobile phase of 0.5% KH2PO4 (pH 6.0)-acetonitrile (30:70, v/v) on a CAPCELLPAK C18 MGII column at a flow rate of 0.5 mL/min and ultraviolet absorbance at 260 nm.
  
  
  RESULTS
  The analysis required 200 microL of plasma and involved a rapid, simple solid-phase extraction with an Oasis HLB cartridge, which resulted in recoveries of 87-92% for itraconazole and 91-94% for hydroxyitraconazole. The lower limit of quantification for itraconazole and hydroxyitraconazole was 5 ng/mL each. Intra- and interday coefficients of variation for itraconazole and hydroxyitraconazole were less than 11.3% and 12.2%, respectively, and accuracies were within 11.7% and 4.5% over the linear range, respectively. Although the steady-state plasma concentrations of itraconazole and hydroxyitraconazole ranged from 506 to 2482 ng/mL and from 766 to 2444 ng/mL, respectively, after a two-day loading dose of 400 mg/day intravenous itraconazole followed by the administration of 200 mg/day itraconazole oral solution, calibration curves of itraconazole and hydroxyitraconazole showed positive linearity in a concentration range of 5-2500 and 50-2500 ng/mL, respectively.
  
  
  CONCLUSIONS
  Our results indicate that this method is applicable for the monitoring of plasma levels of itraconazole and hydroxyitraconazole in a clinical setting. Furthermore, the regimen presented here might also be effective in preventing infection, but further studies with large sample sizes are necessary to investigate this avenue.
authors.affiliation: Department of Pharmacy, Akita University Hospital, 1-1-1 Hondo, Akita 010-8543, Japan. m-miura@hos.akita-u.ac.jp
authors.forename: M
authors.initials: M
authors.lastname: Miura
authors.forename: N
authors.initials: N
authors.lastname: Takahashi
authors.forename: M
authors.initials: M
authors.lastname: Nara
authors.forename: N
authors.initials: N
authors.lastname: Fujishima
authors.forename: H
authors.initials: H
authors.lastname: Kagaya
authors.forename: Y
authors.initials: Y
authors.lastname: Kameoka
authors.forename: H
authors.initials: H
authors.lastname: Saitoh
authors.forename: H
authors.initials: H
authors.lastname: Tagawa
authors.forename: K
authors.initials: K
authors.lastname: Sawada
mesh_terms: D001774:Blood Chemical Analysis / Q000379:methods*; D002138:Calibration; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D004355:Drug Stability; D006801:Humans; D017964:Itraconazole / Q000031:analogs & derivatives* / Q000097:blood* / Q000302:isolation & purification / Q000493:pharmacokinetics*; D052616:Solid Phase Extraction; D014466:Ultraviolet Rays
chemical_list: C084794:hydroxyitraconazole; D017964:Itraconazole