A simple, sensitive, and reliable spectrophotometric method was developed and validated for the quantitative determination of topiramate in both pure form and pharmaceutical preparations. The proposed method is based on the formation of a colored complex through the reaction of topiramate with 1,2-naphthoquinone-4-sulfonate (NQS) reagent in an alkaline medium. The resulting derivative exhibited a maximum absorbance at 527 nm, confirming a significant bathochromic shift from the native drug absorption at 270 nm. Experimental parameters affecting the reaction, including NQS concentration, reagent volume, and drug volume, were carefully optimised to achieve maximum sensitivity. Under the optimised conditions, a linear calibration curve was obtained over the concentration range of 10–200 µg mL⁻¹ with an excellent correlation coefficient (R² = 0.9964). Stoichiometric studies using Job’s continuous variation and mole-ratio methods revealed a 1:1 complex formation between topiramate and NQS. The method demonstrated high accuracy and precision, as indicated by low %RSD and satisfactory recovery values. Furthermore, the low limits of detection (LOD) and quantification (LOQ) confirm the high sensitivity of the proposed method. The developed spectrophotometric approach offers a rapid, cost-effective, and dependable alternative for routine quality control analysis of topiramate in pharmaceutical dosage forms.
Topiramate; Spectrophotometry; (NQS); Pharmaceutical analysis; Electrochemical determination
. Spectrophotometric Determination of Topiramate Using NQS Reagent in Pharmaceutical Formulations. Indian Journal of Modern Research and Reviews. 2025; 3(11):64-71
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