The current investigation described a sensitive, selective, precise and accurate RP-HPLC method with photodiode array detector for the simultaneous estimation of antiviral drugs, grazoprevir and elbasvir. The separation and analysis were done on Sunsil C18 analytical column (250 mm x 4.6 mm, 5 ? particle size). 0.1M NaH2PO4: methanol [60:40 v/v] in isocratic elution mode was used as mobile phase. The pH of the mobile was adjusted to 4.0 with orthophosphoric acid. The elution of grazoprevir and elbasvir was accomplished with a flow rate of 1.2 ml/min. Detection was performed with photodiode array detector set at a wavelength of 260 nm. The detector response was linear in the concentration of 25-75 ?g/ml for elbasvir and 50-150 ?g/ml for grazoprevir. The limit of detection and limit of quantitation values were found to be 0.137 ?g/ml and 0. 574 ?g/ml for elbasvir and 0.290 ?g/ml and 0.968 ?g/ml for grazoprevir, respectively. The method was validated following international conference on harmonization guidelines. The percentage recovery for grazoprevir and elbasvir were found to be in the range of 100.08%-100.45% and 99.60%-100.06%, respectively. The %RSD values are 0.130% and 0.161% for grazoprevir and elbasvir, respectively. The results of validation parameters were found in the acceptance range. The present investigation concluded that the RP-HPLC method with photodiode array detector method was selective for simultaneous estimation of elbasvir and grazoprevir in combined dosage form.
