Simultaneous determination of elbasvir and grazoprevir in their pharmaceutical formulation by synchronous fluorescence spectroscopy coupled to dual wavelength method.

In the present study, a sensitive, selective and accurate synchronous fluorescence spectroscopic method was utilized for simultaneous estimation of elbasvir and grazoprevir in their pharmaceutical formulation. The developed method based on measurement of the synchronous fluorescence intensity of the studied drugs at constant wavelength difference (Δλ) = 50 nm. Elbasvir can be determined directly at 312 nm without interference from grazoprevir. Grazoprevir can be determined by application of dual wavelength method by taking the difference in synchronous fluorescence intensity at 390 & 372 nm to remove interference from elbasvir. Calibration graphs were found to be linear over the concentration range of 50-700 ng/mL for elbasvir and 100-900 ng/mL for grazoprevir. The developed method was successfully applied to the quantitative analysis of the two drugs in Zepatier® tablets.