Novel 96-Microwell-Based Spectrophotometric Assay With High-Throughput For Pharmaceutical Quality Control Of Reboxetine

This study describes the development and validation of a novel 96-microwell-based spectrophotometric assay with high-throughput for pharmaceutical quality control of reboxetine (RBX), the new antidepressant drug. The reaction between RBX and 1,2-naphthoquinone-4-sulphonate (NQS) as a chromogenic reagent was investigated. In alkaline medium (pH 8.5), a red-colored product exhibiting maximum absorption peak (lambda(max)) at 468 nm was produced. The stoichiometry of the reaction was determined and the reaction mechanism was postulated. This color-developing reaction was employed, for the first time, in the development of the proposed assay. The assay reaction was carried out in 96-microwell assay plate and the absorbance of the colored-product was measured by microwell plate reader at 450 nm. The optimized reaction conditions were established; under which, Beer's law was obeyed in the range of 40-600 mu g/mL with good correlation coefficient (0.9992). The limits of detection and quantification were 11.5 and 38.2 mu g/mL, respectively. The assay showed high precision as the values of relative standard deviations (RSD) did not exceed 2%. No interference was observed from the excipients that are present in RBX-containing tablets. The proposed assay was applied successfully for the determination of RBX in its tablets with good accuracy and precisions; the label claim percentage was 102.81 +/- 1.43%. The results were compared favorably with those of a reference method. The results demonstrated that the proposed assay has great practical value in routine application for determination of RBX in pharmaceutical quality control laboratories.