Optimization and Validation of the Spectrophotometric Methods for the Assay of Dexmedetomidine Hydrochloride in Pure and Dosage Forms

Four simple, precise, low-cost, sensitive, and diversely applicable UV-Vis spectrophotometric methods have been developed for the assay of dexmedetomidine hydrochloride in pure and pharmaceutical dosage forms. The methods are based on the oxidation of the drug by N-bromosuccinimide (NBS) (excess) at room temperature and estimating the amount of unconsumed NBS by amaranth dye at λ_max = 530 nm (method A), safranin dye at λ_max = 530 nm (method B), aniline blue at λ_max = 610 nm (method C), or rhodamine B at λ_max = 560 nm (method D). Regression analysis of Beer–Lambert's plots proves excellent correlation in the concentration ranges 2–9, 4–11, 2–10, and 1.2–3.5 μg/mL for methods A, B, C, and D, respectively. The apparent molar absorptivity, Sandell's sensitivity, and detection and quantification limits are calculated. The proposed methods can be applied to drug formulation and recommended for routine analysis in quality control laboratories. Statistical comparison of the results with the reference method shows excellent agreement.