Analytical Techniques for Baloxavir Marboxil: A Critical Review of Chromatographic, Mass Spectrometric, and Emerging Methods (2018–2025)

Abstract

PURPOSE: Baloxavir Marboxil, a first-in-class cap-dependent endonuclease inhibitor, is a prodrug used in influenza therapy. Reliable analytical methods are essential for its quantification in pharmaceutical formulations and biological matrices to support drug development, quality control, and pharmacokinetic studies. This review evaluates current analytical approaches, and future directions. METHODS: A systematic literature search identified relevant analytical studies, which were critically compared based on principles, validation performance, and applicability. RESULTS: UHPLC-MS/MS is considered the gold standard, offering high sensitivity (LLOQ as low as 0.1 ng/mL), strong selectivity, and simultaneous determination of baloxavir marboxil and its active metabolite. Sample preparation techniques, particularly protein precipitation and liquid-liquid extraction, significantly influence method performance, while isotopically labeled internal standards effectively minimize matrix effects. The compound shows pronounced instability under alkaline conditions, whereas oxidative, thermal, and photolytic degradation are relatively limited. Emerging spectrofluorimetric methods provide greener alternatives but with reduced sensitivity and limited bioanalytical applicability. CONCLUSION: This review compares major analytical platforms, highlights regulatory validation requirements, and discusses clinical applications including therapeutic drug monitoring. It underscores the need for standardized, high-throughput, and sustainable analytical methods to support future research and clinical implementation.