An RP-HPLC Method for the Simultaneous Analysis of Selected Antiviral Drugs

Abstract

A rapid and efficient reversed-phase high-performance liquid chromatography (RP-HPLC) method was developed and validated for the simultaneous determination of six antiviral drugs: emtricitabine (EMT), entecavir (ENT), favipiravir (FAV), ganciclovir (GAN), valaciclovir (VAL), and valganciclovir (VLG). Chromatographic separation was achieved on an ExsilTM Mono 100 C18 column using a mobile phase of 50 mM phosphate buffer (pH 4): acetonitrile (90:10, v/v) at a flow rate of 0.5 mL/min. UV detection was performed at 215 nm. The method was validated according to ICH Q2(R2) guidelines, demonstrating excellent linearity (R² > 0.9938) across the concentration ranges of 1.0–150 μg/mL for EMT, ENT and VLG, and 5.0–200 μg/mL for FAV, GAN and VAL. The LOD and LOQ values ranged from 0.02 to 0.48 μg/mL and 0.05 to 1.45 μg/mL, respectively. Intra-day and inter-day precision, expressed as relative standard deviation (RSD), were less than 1.82%, while accuracy, expressed as relative error (RE), was within ± 1.34%. Recovery studies yielded values ranging from 98.12% to 101.60%, further confirming method accuracy. The method proved to be selective, robust, and suitable for the quantitative analysis of these antiviral drugs in pharmaceutical formulations, with results obtained for commercially available tablets demonstrating excellent agreement with labeled contents. Notably, stability studies revealed the susceptibility of EMT, ENT, and FAV to degradation under refrigerated storage, highlighting the need for timely analysis of these compounds. In addition, the greenness, blueness, and whiteness of the method were evaluated, and the developed method performs strongly across environmental (AGREE score: 0.79), practical (BAGI index: 85), and sustainability (whiteness value: 74.7) criteria, reinforcing its viability as a sustainable approach for antiviral analysis. This validated RP-HPLC method provides a reliable and efficient tool for the quality control of these essential antiviral medications.