LC–MS/MS characterization of forced degradation products of zofenopril

•First report on characterization of stress degradants of zofenopril.•First report on ESI-MS/MS fragmentation pathways of zofenopril and degradation products.•Developed and validated a stability indicating assay of zofenopril. A rapid, specific and reliable isocratic LC–MS/MS method has been developed and validated for the identification and characterization of stressed degradation products of Zofenopril. Zofenopril, an anti-hypertensive drug, was subjected to hydrolysis (acidic, alkaline and neutral), oxidation, photolysis and thermal stress, as per ICH-specified conditions. The drug showed extensive degradation under oxidative and base hydrolysis stress conditions. However, it was stable to thermal, acid, neutral and photolysis stress conditions. A total of 6 degradation products were observed and the chromatographic separation of the drug and its degradation products were achieved on Phenomenex (Luna) C18 (250mm×4.6mm, i.d., 5μm) column using 20mM ammonium acetate: 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 zofenopril.