Green Sensitive Derivative Emission Spectrofluorimetry for the Estimation of Repaglinide and Febuxostat...

A simple, rapid, precise, and selective first derivative spectrofluorimetric (¹D) technique was suggested for repaglinide (REP) and febuxostat (FEB) simultaneous quantitation in pure, spiked human plasma samples and dosage forms. The approach was based on the first derivative transformation of the conventional fluorescence emission spectra. Excitation was fixed at 250 nm, and the first derivative of the emission spectra was recorded for each sample. Repaglinide (REP) was measured at 336.5 nm and febuxostat (FEB) at 363.5 nm in presence of each other using 0.2-M acetate buffer pH 3.9. Several experimental factors were examined and adjusted based on their effect on the fluorescence intensity. The validation was performed in accordance with ICH guidelines and the amplitude first derivative (¹D) versus concentrations curves covered concentration ranges of 0.01-0.18 μg/mL for REP and 0.03-0.2 μg/mL for FEB. The quantification limits (LOQs) were 0.007 and 0.026 μg/mL for (REP) and (FEB), whereas lower detection limits (LODs) were 0.002 and 0.009 μg/mL, respectively. The suggested approach was effectively used to determine the two drugs in spiked human plasma samples in ranges 0.01-0.2 μg/mL for REP and 0.05-0.2 μg/mL for FEB. The proposed technique was effectively used to identify the (REP) and (FEB) in multiple pharmaceutical products.