Development and Validation of Eco-Friendly Spectroscopic Methods for the Determination of Sofosbuvir Using Eosin Y as an Ion Pairing Reagent

This paper presents two novel, simple and rapid spectroscopic methods for the selective determination of Sofosbuvir (SFV) that take advantage of the formation of a binary complex ion pair between SFV and eosin Y in a 0.4 M acetate buffer with a pH of 3.5. The 1^st method is a spectrophotometric one and is based on measuring the absorbance of SFV-eosin ion pair complex at 535 nm. This method was shown to be linear over the concentration of 2.0 – 8.0 µg/mL. The second method is a spectrofluorimetric one and is based on measuring the fluorescence of SFV-eosin ion pair complex at 621 nm after excitation at 320 nm. This fluorescence based method was linear over the range of 0.05-0.5 µg/mL. A thorough evaluation was carried out to assess and validate the analytical performance of the proposed methods. The investigation produced satisfactory results. Commercial tablets containing SFV were successfully assayed by means of the developed methods. The obtained results were benchmarked against those of the applied comparison method. The two sets of results coincided neatly. The developed methods are sensitive, rapid, cost-effective and environmentally friendly.