Liquid Chromatography-Mass Spectrometry for Simultaneous Determination of Spironolactone and Canrenone in Plasma Samples

The document presents a validated method using liquid chromatography-mass spectrometry (LC-MS) for simultaneously quantifying spironolactone (SPI) and its active metabolite canrenone (CAN) in plasma samples. The method demonstrated linearity in the concentration range of 0.4 to 5.0 µg mL−1, with a coefficient of variation less than 5%, and recovery rates for SPI and CAN from plasma ranging from 87.4% to 112.1%. The limits of detection for SPI and CAN were 0.07 μg mL−1 and 0.03 μg mL−1, respectively, and their limits of quantification were 0.20 μg mL−1 and 0.08 μg mL−1, respectively. Despite the interference of plasma, the method was deemed feasible for use in pharmacokinetic studies of medicines containing SPI.