Determination of Antithyroid Drug Propylthiouracil with Ru (III) in Pharmaceutical Formulations and its Characterization

Background: Sulfur serves as a versatile element and an essential constituent of pharmaceutical industries, natural compounds, proteins, and biological systems. One of the fundamental constituents of sulfur is thiouracil, which forms several derivatives, including 6- methylthiouracil, 6-methyl-2-thiouracil, and 6-propylthiouracil. These derivatives act as effective chelating agents and can form complexes with metal ions. Compared with other metals, ruthenium possesses unique chemical properties that make it an ideal therapeutic agent. Therefore, this study reports on the propylthiouracil: Ru(III) complex, considering these essential facts. Methods: An equimolar amount of ruthenium trichloride 3.34 x 10^-5 M was added to various aliquots ranging from 0.4 mL to 8.8 mL of 3.26 x 10^-5 M propylthiouracil. The volume was adjusted to 10 mL with double distilled water. After letting the solution stand for 10 min, we recorded the absorbance of different sets at λmax 376 nm. The Beer-Lambert's law graph demonstrated linearity in the concentration range of 3.18 x10¹ μgmL^-1 to 7.96 x10² μgmL^-1, with a linear regression equation of Y = 0.0354 + 0.1109 X. We determined the effective molar absorptivity (ε) to be 6.609 x 10² Lmole^-1 cm^-1, and the relative standard deviation (RSD %) was ± 0.34%. Results: At room temperature, a yellow-colored complex of propylthiouracil: Ru(III) was formed within 10 min, with a λmax of 376 nm and constant color intensity for 24 h. We confirmed and characterized the formed complex using FTIR, ESR, 1HNMR, thermal analysis, magnetic susceptibility, and powder X-ray. Conclusion: This approach is notable for its precision, accuracy, rapidity, cost-effectiveness, and applicability in tablet form. The novel propylthiouracil: Ru(III) complex offers several advantages, including stability, low absorbance, and no interference with water-soluble ions, eliminating the need for an organic solvent to extract the reaction product. Therefore, this approach could be recommended for quality control in the pharmaceutical industry.