Rapid determination of minoxidil in human plasma using ion-pair HPLC

J Pharm Biomed Anal. 2004 Oct 29;36(2):377-9. doi: 10.1016/j.jpba.2004.06.007.


A rapid, simple and sensitive ion-pair high-performance liquid chromatography (HPLC) method has been developed for quantification of minoxidil in plasma. The assay enables the measurement of minoxidil for therapeutic drug monitoring with a minimum detectable limit of 0.5 ng ml(-1). The method involves simple, one-step extraction procedure and analytical recovery was complete. The separation was performed on an analytical 150 x 4.6 mm i.d. microbondapak C18 column. The wavelength was set at 281 nm. The mobile phase was a mixture of 0.01 M sodium dihydrogen phosphate buffer and acetonitrile (60:40, v/v) containing 2.5 mM sodium dodecyl sulphate adjusted to pH 3.5 at a flow rate of 1 ml/min. The column temperature was set at 50 degrees C. The calibration curve was linear over the concentration range 2-100 ng ml(-1). The coefficients of variation for inter-day and intra-day assay were found to be less than 8%.

Publication types

  • Clinical Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Chromatography, High Pressure Liquid
  • Drug Stability
  • Humans
  • Minoxidil / blood*
  • Minoxidil / pharmacokinetics
  • Reference Standards
  • Reproducibility of Results
  • Solutions
  • Spectrophotometry, Ultraviolet
  • Vasodilator Agents / blood*
  • Vasodilator Agents / pharmacokinetics


  • Solutions
  • Vasodilator Agents
  • Minoxidil