Quantification of Aceclofenac and Pregabalin in Pharmaceutical Formulations using Nucleophilic Aromatic Substitution Reactions

Abstract

Aceclofenac and Pregabalin in combination have significant reduction in pain as compared to individual drug in chronic low back pain. Literature reveals that all the reported spectrophotometric methods are either need tedious extraction procedures do not offer high sensitivity, uses non specific reagent and/or recommend the measurement of absorbance in the near UV region where interference most probably occurs that do not offer suitable linearity range. A novel, accurate, precise and extraction free UV spectrophotometric method has been developed for simultaneous estimation of Aceclofenac and Pregabalin in combined dosage form. The method employed was Dual wavelength method. The method is based on the reaction of Pregabalin with 1,2-naphthaquinone-4-sulphonate sodium, yielding an orange colored product. The different experimental parameters affecting the development and stability of the reaction product were carefully studied and optimized. Method involves measurement of Aceclofenac at 268.5 and 280.0 nm and measurement of Pregabalin at 324.0 and 339.5 nm. Rectilinear relationship with good regression coefficient 0.999 and 0.999 were found over the concentration ranges of 5-25 μg/ml and 3.75-18.75 μg/ml for Aceclofenac and Pregabalin, respectively with detection limit 0.62 and 0.50 μg/ml and Quantitation limit 1.87 and 1.52 μg/ml. The mean percentage recoveries were ranged 99.60 – 99.83 and 98.85 – 100.05 for Aceclofenac and Pregabalin, respectively. The developed methods were successfully applied to the analysis of the drug in its commercial tablet.