New Spectrophotometric Determination of Nebivolol in Pharmaceutical Formulation via Charge Transfer Complex

New simple, sensitive, selective and rapid spectrophotometric methods were developed for the determination of Nebivolol (NBV) in pharmaceutical formulation. The methods are based on charge transfer complexation reaction of NBV as n-electron donor with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ), 2,4-dinitrophenol (DNP) and 2,4,6-trinitrophenol (picric acid; PA) as π-acceptors to give highly colored radical anion species. The colored products were quantified spectrophotometrically at 620nm with DDQ (method A), at 525nm with both DNP (method B) and at 500nm with PA (method C). Under the optimized experimental conditions, Beer's law was obeyed over the concentration ranges 4.0-40, 2-25 and 1.0-35 μg/mL with correlation coefficient 0.9983, 9945 and 0.9985 for methods A, B and C respectively. Other method validation parameters, such as precision, accuracy, robustness, ruggedness and selectivity, were satisfactory. The proposed methods were successfully applied to the determination of NBV in commercial tablets. No interference was observed from common tablet adjuvants. Statistical comparison of the results with the reference method showed excellent agreement and indicated no significant difference in accuracy and precision.