Trends and Advances in Analytical Methodologies for Favipiravir Determination Across Diverse Matrices.

Favipiravir, a broad-spectrum antiviral agent used against RNA viral infections, has been quantified in bulk drugs, pharmaceutical formulations, and biological matrices using various analytical approaches. This review critically evaluates reported methods, including UV-Vis spectrophotometry, spectrofluorimetry, electrochemical sensing, planar chromatography, and advanced chromatographic techniques. UV-Vis methods offer simplicity, low cost, and potential use of green solvents, whereas spectrofluorimetric methods provide enhanced sensitivity. Electrochemical sensors employing nanostructured materials and molecularly imprinted polymers enable rapid, portable, and sensitive detection, particularly in biological matrices. Planar chromatography provides cost-effective and high-throughput analysis with low solvent consumption, increasingly supported by densitometric and digital image-based quantification. RP-HPLC, UPLC, and LC-MS remain the most robust techniques, offering superior selectivity, resolution, and reproducibility for pharmaceutical, stability, and pharmacokinetic studies. Recent developments emphasize green analytical chemistry, chemometric-assisted analysis, quality-by-design optimization, and smartphone-based detection. However, incomplete validation and robustness assessment remain limitations in several reported methods. Overall, this review provides a comparative perspective on favipiravir analytical strategies and highlights future needs for standardized, sensitive, sustainable, and intelligent analytical methods.