Delapril and Manidipine Measurements by Liquid Chromatography—Tandem Mass Spectrometry in a Pharmaceutical Formulation

A simple, specific, fast and sensitive liquid chromatography–tandem mass spectrometry (LC-MS/MS) method for the simultaneous analysis of delapril (DEL) and manidipine (MAN) from their combination formulation was developed and validated using fesoterodine as the internal standard (IS). The LC-MS/MS method was carried out on a Luna C₈ column (50 × 3.0 mm i.d., 3 μm) with a mobile phase consistingof methanol and 10 mmol L⁻¹ ammonium acetate (90:0, v/v), run at a flow rate of 0.25 mL min⁻¹. The mass spectrometry method was performed employing positive electrospray ionization operating in multiple reaction monitoring mode, monitoring the transitions of m/z 453.1 → 234.1 for DEL, m/z 611.1 → 167.0 for MAN and m/z 412.2 → 223.0 for IS. The total analysis time was 3 min and the method was linear in the concentration range of 6–1080 ng mL⁻¹ and 2–360 ng mL⁻¹ for DEL and MAN, respectively. Parameters investigated for the method validation, such as the specificity, linearity, precision, accuracy and robustness, gave results within the acceptable range. Moreover, the proposed method was successfully applied for the simultaneous determination of DEL and MAN and the results were compared to validated liquid chromatography and capillary electrophoresis methods showing non-significant differences (P = 0.9).