ABSTRACT:
Daclatasvir and Sofosbuvir are recently co-formulated as antiviral combination for treatment of hepatitis C virus (HCV). Several spectrophotometric methods were developed and validated for determination of the partially overlapped spectra of Daclatasvir and Sofosbuvir with simple data manipulation. Daclatasvir can be directly determined at 316.0 nm with in a linear range of 2.5-25.0 µg/mL. Three approaches were applied for determination of Sofosbuvir; the first is using dual wavelength method at which the absorbance difference between 350.0nm and 270.0nm was recorded and absorption subtraction method where the two drugs have an isosbestic point at 272.0nm. The second approach is derivative spectroscopy using first derivative method, Sofosbuvir can be determined at 253.0nm at which Daclatasvir showed a zero crossing point. The third approach is manipulation of ratio spectra using ratio difference method at which the overlapping spectra of Sofosbuvir divided by a divisor from Daclatasvir where the difference in peak amplitude measured at 257.0nm and 228.0 nm. Ratio derivative method was also applied at which the first derivative corresponding to each ratio spectrum was recorded then the amplitude values were measured at 270.0nm. In these methods Sofosbuvir showed linearity in the range of 10.0-80.0 µg/mL. These methods were validated according to ICH guidelines and was successfully applied to pharmaceutical formulation and showed nonsignificant difference when compared to a well established published method.