A critical review of analytical tools for the detection of spironolactone and its metabolites

Spironolactone (SPI) is a synthetic aldosterone antagonist steroid used to treat various conditions, including hypertension, heart failure, primary hyperaldosteronism, and androgen-related disorders. SPI undergoes extensive hepatic metabolism via cytochrome P450 to active derivatives, including canrenone. Accurate determination of SPI and derivatives is important for pharmacokinetic profiling, therapeutic drug monitoring, pharmaceutical quality control, and environmental monitoring. However, spiking of analyte concentration, chemical instability, matrix complexity, and low analyte levels, which require more sensitive instrumentation, present challenges for analytical determination. Although several methodologies, including spectrophotometric, chromatographic, and electroanalytical techniques, have been reported in the last thirty years, high-performance liquid chromatography (HPLC) and particularly HPLC coupled with tandem mass spectrometry (LC-MS/MS) is the most robust, sensitive, and flexible of these methods for measuring SPI and its metabolites in various matrices. In addition, several sample-preparation techniques, such as Protein Precipitation (PP), liquid-liquid extraction (LLE), and solid-phase extraction (SPE), have been applied with HPLC or LC-MS/MS to enhance analytical performance by minimizing interferences from the complex matrix. This review critically evaluates measurement methodologies in the literature for SPI, focusing on their development, advantages, and disadvantages, and emerging trends toward rapid, inexpensive, and miniaturized platforms. Based on its analytical performance, reproducibility, and applicability, LC-MS/MS (and HPLC)-based methodology is the most suitable for comprehensive SPI analysis.