Determination of Finasteride in Human Plasma by Liquid Chromatography-Electrospray Ionization Tandem Mass Spectrometry with Flow Rate Gradient

In 2010, researchers developed a sensitive and rapid method using liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) to measure finasteride in human plasma. The method, which required only 0.1 mL of plasma, featured a flow rate gradient and liquid-liquid extraction, resulting in a linear calibration curve from 0.2-100 ng/mL and a lower limit of quantification of 0.2 ng/mL. The extraction recoveries for finasteride were above 82.7%, with intra- and inter-day precision ranging from 2.4-8.0% and accuracy between 94.3-105.8%. This method, which reduced analysis time to 3.6 minutes and improved sensitivity, was successfully used in pharmacokinetic or bioequivalence studies, including one involving a single 5 mg oral dose of finasteride. The study concluded that this method offers advantages such as improved sensitivity and selectivity, shorter run time, and lower environmental impact, making it suitable for various studies in human subjects.