LC–MS/MS method for the characterization of the forced degradation products of Entecavir

A rapid, specific, and reliable isocratic LC–MS/MS method has been developed and validated for the identification and characterization of the stressed degradation products of Entecavir (ETV). ETV, an antiviral drug, was subjected to hydrolysis (acidic, alkaline, and neutral), oxidation, photolysis and thermal stress, as per the international conference on harmonization specified conditions. The drug showed extensive degradation under oxidative and acid hydrolysis stress conditions. However, it was stable to thermal, acidic, neutral, and photolysis stress conditions. A total of five degradation products were observed and the chromatographic separation of the drug and its degradation products were achieved on a Waters Symmetry C₁₈ (250 mm × 4.6 mm, id, 5 μm) column using 20 mM ammonium acetate (pH 3)/acetonitrile (50:50, v/v) as a mobile phase. The degradation products were characterized by LC–MS/MS and its fragmentation pathways were proposed. The LC–MS method was validated with respect to specificity, linearity, accuracy, and precision. No previous reports were found in the literature regarding the degradation behavior of ETV.