Development and Validation of a Liquid Chromatography Method for the Simultaneous Estimation of Sulfadoxine and Pyrimethamine in Combined Dosage Forms

Abstract

The final method employed a Platisil C18-ODS column (250×4.6 mm, 5 µm) with a mobile phase of 50% 0.1% formic acid (pH 4.5) and 50% methanol, at a flow rate of 1.0 ml/min, and UV detection at 230 nm. System suitability parameters such as retention time, theoretical plates, and tailing factor were within acceptable limits, confirming the method’s efficiency and reliability. Validation was performed according to ICH Q2(R1) guidelines, demonstrating excellent analytical performance. Assay results showed drug content of 99.1% for Sulfadoxine and 98.6% for Pyrimethamine. Linearity was observed over wide concentration ranges with correlation coefficients of 0.9997 and 0.9996, respectively. Precision and intermediate precision studies yielded %RSD values below 2%, indicating high repeatability and ruggedness. Recovery studies confirmed accuracy within the 98–102% range, while LOD and LOQ values (0.02 µg/ml for Sulfadoxine and 0.05µg/ml for Pyrimethamine) highlighted the method’s sensitivity. Robustness testing under slight variations in flow rate and mobile phase composition showed consistent results, affirming the method’s suitability for routine quality control of combined dosage formulations.