Green mathematical approaches in fluorescence spectroscopy for quality control and clinical studies

In the past decade, significant advancements have been made in mathematical spectral approaches for estimating binary and ternary drug combinations in raw materials and dosage forms. These approaches established on mathematical spectral manipulations of mixture analytes, without the need for separation techniques. The idea of using mathematical spectral approaches in fluorescence spectroscopy was resolving analytical issues and reach to biological concentrations thus, Ratio subtraction (RD) and ratio subtraction coupled with constant multiplication (RS-CM) have been proposed in fluorescence spectroscopy to evaluate the content uniformity of Flunarizine dihydrochloride (FLZ) and Propranolol hydrochloride (PRO) combination in raw materials, tablets, and spiked biological fluids (blood-urine). These approaches have demonstrated the ability to overcome the quantitative analytical challenges posed by the high native fluorescence intensity of the major component (PRO) at 2ex = 286/2em = 341 nm and the low native fluorescence intensity of the minor component (FLZ) at 2ex = 254/2em = 311 nm. The linearity range for (PRO) was found to be 25-500 ng/mL, and for (FLZ), it was 50-500 ng/mL. However, the spectrum addition technique was required to estimate (FLZ) in mixtures with concentrations less than 300 ng/mL. The overall validity of the proposed approaches was confirmed through adherence to ICH guidelines, and no statistical variation was observed in comparison to official studies. Additionally, the greenness and whiteness of the proposed approaches were evaluated using the Analytical greenness metric (AGREE), Green Solvents Selecting Tool (GSST), and Red-Green-Blue (RGB) algorithm.