Abstract
Two sensitive and accurate spectrophotometric methods has been developed for estimation of ezetimibe (EZT) in pure and dosage forms. The proposed methods is based on oxidation reaction of EZT with a known excess of N-bromosuccinimide (NBS) or cerium(IV) ammonium sulphate (CAS) as an analytical reagents in acid medium followed by determination of unreacted oxidant by adding a fixed amount of amaranth (AM), methylene blue (MB), indigocarmine (IC) or orange G (OG) dyes followed by measuring the absorbance at 520, 664, 610 or 478 nm, respectively. The experimental conditions affecting the reaction were studied and optimized. The beer’s law was obeyed in the concentration ranges of 2.0-20, 2.0-12, and 2.0-12 μg mL-1 in case of NBS using AM, IC and MB dye, respectively and and 2.0-18, 2.0-12 and 2.0-15 μg mL-1 in case of CAS using AM, OG and MB dye, respectively with a correlation coefficient ≥ 0.9992. The calculated molar absorptivity values are 0.7855× 104, 0.7255 × 104, and 2.7204 × 104 L mol-1 cm-1 for method A using AM, MB and IC dyes, respectively and 0.9246 × 104, 1.3612× 104 and 0.8658 × 104 L mol-1 cm-1 for method B using AM, MB and OG dyes, respectively. The limits of detection and quantification were reported. Intra-day and inter-day accuracy and precision of the methods have been evaluated. No interference was observed from the additives and the applicability of the method was tested by analyzing the pharmaceutical preparations containing the investigated drug. The proposed methods were successfully applied to the assay of EZT in tablet preparations and the results were statistically compared with those of the reported method by applying Student’s t-test and F-test. The reliability of the methods was further ascertained by performing recovery studies using the standard addition method.
