SPECTROPHOTOMETRIC DETERMINATION OF METHYLDOPA IN ITS PHARMACEUTICAL PREPARATIONS USING OXIDATION-COUPLING REACTION WITH CEFOTAXIME REAGENT

In order to estimate methyldopa in both its pure form and in pharmaceutical formulations, a very sensitive spectrophotometric approach was developed. The process involves oxidizing methyldopa in an acidic media with an excess of potassium periodate (KIO₄). The cefotaxime reagent was then applied to the released methyldopa, resulting in the formation of a colored complex with maximum absorbance at 408 nm. the linearity of the standard calibration curve in the 1.0–20.0 μg/ml methyldopa concentration range, with a correlation coefficient of 0.9991. The Sandell's sensitivity index was 0.0258 μg/cm², and the molar absorptivity was 8.17×104 L/mol/cm². After calculations, the limits of quantification and detection were determined to be 0.784 and 0.303 μg/mL, respectively. The precision (RSD%) and the recovery were also estimated and found to be in the ranges of 0.639 to 0.941 and 98.97% to 100.77%, respectively. Methyldopa in accessible dosage forms, such as tablets, has been estimated using this method.