A Novel Simple First‐Derivative Synchronous Spectrofluorimetric Approach for Dual Estimation of Duloxetine and Mirtazapine in Dosage Forms and Biological Human Plasma

A sensitive spectrofluorimetric approach was developed for simultaneous measurement of duloxetine (DUL) and mirtazapine (MIR) in pharmaceutical dosage forms and human plasma as well. The method depends on first-derivative synchronous spectrofluorometric scan where DUL and MIR were measured at 272 and 336 nm, respectively using Δλ of 60 nm. Both drugs are co-administered in resistant depression. The linearity was attained over the ranges of 0.1-1.3 μg/mL and 0.1-1.5 μg/mL for DUL and MIR, respectively. The limit of detection was found to be 0.013, while the limit of quantitation was found to be 0.042 for both drugs. The method gives high percentage recoveries of 98.27%-101.29% for DUL and 99.55%-101.69% for MIR when determining both analytes in their dosage forms. The two analytes were estimated in human plasma using the described approach achieving excellent percentage recoveries ranging from 98% to 101.33%. This is so important for quality control laboratories and pharmacokinetic studies. ICH criteria were used to validate the adopted procedure. The method's sustainability is evaluated by applying different tools, namely, Analytical Green Star Area (AGSA), Multi-Color Assessment (MA) Tool, analytical eco-scale, the Analytical Greenness Calculator (AGREE), Green Analytical Procedure Index (GAPI) and Blue Applicability Grade Index (BAGI).