Bioanalytical Method Validation of LC–MS/MS Assays for Trazodone: A Critical Review Based on USFDA and ICH M10 Guidelines

Trazodone (TZD) is widely used for the treatment of major depressive disorder, anxiety-related disorders, and insomnia. Accurate quantification of TZD in biological matrices is essential for pharmacokinetic, bioavailability, and bioequivalence studies. Liquid chromatography coupled with tandem mass spectrometry (LC–MS/MS) has become the preferred technique for TZD bioanalysis because of its high sensitivity, selectivity, and ability to analyze complex biological samples. This review critically evaluates reported LC–MS/MS bioanalytical methods developed for the determination of TZD in human plasma, with special emphasis on bioanalytical method validation parameters in accordance with United States Food and Drug Administration (USFDA) and International Council for Harmonisation (ICH M10) guidelines. Key validation parameters including selectivity, linearity, accuracy, precision, recovery, matrix effect, stability, carryover, and dilution integrity are discussed and compared across reported studies. In addition, commonly observed gaps in regulatory compliance are identified and practical recommendations are proposed for improving analytical robustness. The review also highlights emerging regulatory expectations and analytical trends in LC–MS/MS bioanalysis. Overall, this work provides a consolidated reference for researchers and bioanalytical scientists involved in TZD analysis and supports the development of robust, regulatory-compliant LC–MS/MS methods.