HPLC-UV and TLC-Densitometry Methods for Simultaneous Determination of Sofosbuvir and Daclatasvir: Application to Darvoni® Tablet.

Sofosbuvir and daclatasvir are co-formulated as directly acting antiviral agents used for treatment of hepatitis C virus. Two chromatographic methods were developed for their determination; the first one is an Reversed phase-high performance liquid chromatography (RP-HPLC) method, in which the separation was performed on C8 Zorbax® SB column (4.6 × 250 mm, 5 μm) using acetonitrile:water:0.05 M phosphate buffer, pH = 8 (50:45:5, v/v/v) as a mobile phase, and ultraviolet detection was performed at 280 nm. Good resolution was obtained, and linearity was confirmed in the range of 10-100 μg/mL for both drugs. The second method is Thin layer chromatography (TLC)-densitometric one, in which sofosbuvir and daclatasvir were separated on silica gel plates using ethyl acetate:hexane:methanol (9:0.5:0.5, v/v/v) as a developing system and the scanning wavelength was 280 nm. Linearity was confirmed over a concentration range of 0.4-25.4 μg/band for sofosbuvir, whereas for daclatasvir linearity scanning was in the range of 0.4-12.8 μg/band. Both antiviral agents can be quantified simultaneously in one analytical run, which is a great time- and cost-saving valor of the developed methods. This valor is even more important in the case of the combined dosage form (Darvoni® tablets) to the pharmaceutical market.