LC-MS/MS characterization of forced degradation products 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.