SIMULTANEOUS ESTIMATION OF SOFOSBUVIR AND LEDIPASVIR USING UV SPECTROPHOTOMETRIC AND RP-HPLC METHODS

The present work includes two simple, inexpensive, rapid, accurate and precise UV spectrophotometric methods and another isocratic RP-HPLC method for estimation of Sofosbuvir (SOFO) and Ledipasvir (LEDI) in bulk and in synthetic mixture. The UV methods are based upon absorption correction (ACM) and first derivative zero crossing point method (FDZC) analysis approach. Chosen wavelength maxima were 260nm and 334nm for SOFO and LEDI respectively for ACM. Whereas for FDZC, estimation of SOFO and LEDI were carried out at 274.5 and 260.6 respectively. Selected linearity ranges for SOFO and LEDI were 24-40 μg/mL and 5.4-9 μg/mL respectively for UV methods. The simple, isocratic RP-HPLC method involved separation of SOFO and LEDI using reverse phase C18 CHROMBUDGET column (250 mm x 4.6 mm,5 μ) having mobile phase composition of acetonitrile and ammonium formate (pH 2.8)::55:45. The developed methods were validated successfully according to ICH Q2 (R1) guideline. Both spectrophotometric and chromatographic methods showed a linear response having r2 values of 0.999. The percentage relative standard deviation (%RSD) was found to be less than two indicating that the methods were precise. The methods were successfully applied for analysis of SOFO and LEDI in laboratory mixture.The mean percentage accuracy values obtained for UV and RP-HPLC methods were between 99-102% and 99-101% respectively. SOFO and LEDI in its formulation could be accurately determined with assay values ranging from 99-101%. Thus it can be concluded that both the developed methods were specific, selective and robust.