RP-HPLC Method Development and Validation for Simultaneous Estimation of Escitalopram Oxalate and Atazanavir Sulphate in Bulk and Dosage Form

Background: This study was designed for the estimation of escitalopram oxalte and atazanavir sulphate in the experimental tablet formulation. The separation was performed at 210 nm by using Inertsil ODS 3V (250 * 4.6 mm, 5.0 m) column and acetonitrile/phosphate buffer (pH =3.55) as the eluent under isocratic elution conditions at a flow rate of 1.0 mL/min. Results: Escitalopram oxalate and atazanavir sulphate peaks were eluted at 2.636 and 3.319 minutes and no interference was observed in the diluent blank at the respective retention times, indicating that the developed method was specific and selective. A linear relationship was found for escitalopram oxalte (2.5 - 15 µg mL-1) and atazanavir sulphate (30 - 150.0 µg mL-1), with coefficient of regression greater than 0.999. Based on the RSD values (< 2.0%) and recovery results (> 98%), the developed method is accurate. At room temperature and in the refrigerated conditions, standard and sample solutions of escitalopram oxalate and atazanavir sulphate have been found to be stable for 48 hours. Conclusion: The established method is linear, precise, accurate, specific, and robust in the studied concentration range. Accordingly, the proposed method can be applied to the analysis of experimental tablet formulations as well as bulk drug samples.