Illuminating the analytical chemistry Profile: A Three-Decade comprehensive review of fluorometric quantitation in pharmaceutical formulations

Abstract

Owing to its high sensitivity and specificity, fluorescence spectroscopy has emerged as a critical analytical tool for pharmaceutical formulations. Over the last three decades, it has been widely used to quantify active pharmaceutical ingredients across various drug formulations owing to its ability to detect trace amounts, even in complex matrices. This review synthesizes the applications of fluorescence spectroscopy in pharmaceutical formulations from 1990 to the present, focusing on advancements in methods, solvents, wavelengths, linearity, and sensitivity metrics, such as LODs and LOQs. The data was compiled from studies involving spectrofluorometric methods for pharmaceutical formulations. The key parameters included the excitation and emission wavelengths, solvents, linearity ranges, LODs, and LOQs, with a comprehensive analysis of the trends and developments in these metrics over time. This review highlights substantial variations in excitation (220–419 nm) and emission wavelengths (292–800 nm), reflecting the diverse chemical structures of the drugs analyzed. Water and methanol are the most commonly used solvents for this purpose. Linearity ranges extended from 0.05--600 ng/mL (e.g., amulpride to etodolac), demonstrating the versatility of fluorescence spectroscopy. The LOD values ranged from 0.007 µg/mL (methocarbamol) to 60 ng/mL (fluvoxamine), indicating high sensitivity. Fluorescence spectroscopy remains an indispensable tool for pharmaceutical quantitation, offering enhanced precision and adaptability to a wide range of drug formulations. Its evolution, characterized by increased sensitivity and methodological refinement, ensures its continued relevance in drug quality assurance and regulatory compliance.