UV-Visible spectrophotometric determination of Vonoprazan Fumarate in Pharmaceutical Formulation through Complex Formation with Cu(II) and Fe(II) ions

A simple, sensitive and reproducible spectrophotometric method is developed for the determination of Vonoprazan(VPZ) in pharmaceutical formulation. The developed method involved the formation of colored binary Complexes I and Complex II between the VPZ and Copper (II) and Iron (II) ions, respectively. The maximum absorbance values for Complex I and Complex II were at wavelengths of 265 nm and 360 nm, respectively. The stoichiometry of the reaction between the VPZ and Copper (II) is found to be 5:5, while for Vonoprazan and Iron (II) was found to be 7:3. The Calibration curve obtained by Beer’s law, has a linear domain in the concentration ranges of 0.001M to 0.01M for both metals. The limit of Detection (LOD, calculated as: LOD = 3 ´ s_a/slope) and the limit of quantification (LOQ, calculated as LOQ = 10 ´ s_a/slope). The estimated values are LOD = 4.24 ´ 10^-7 M and LOQ = 1.41 ´ 10^-6 M for Complex I and LOD = 3.04 ´ 10^-7 M and LOQ = 1.01 ´ 10^-6 M for Complex II, respectively. The validity of the proposed method was assessed. Statistical analysis of the results has been carried out, revealing high accuracy and good precision. The proposed methods for the determination of VPZ in pharmaceutical formulation are rapid, simple, sensitive, and can be comparable with other sophisticated techniques for quality control applications.