DEVELOPMENT AND VALIDATION OF STABILITY-INDICATING RP-HPLC ASSAY METHOD FOR ENTACAPONE IN ENTACAPONE TABLETS

A new, simple, precise, rapid, accurate and stability-indicating RP-HPLC method has been developed for the determination of Entacapone in presence of its degradation products or other pharmaceutical excipients. Stress studies were performed on Entacapone tablets and it was found that it degrades sufficiently in acidic, alkaline and oxidation conditions, while negligible degradation was observed in thermal, photolytic and humidity conditions. The peaks of the degradation products were not observed in the chromatogram due to the nonchromophoric nature of the degradation moiety formed. The separations were carried out on a Hypersil BDS C₈, 150 mm x 4.6 mm 5µm particle size column with a mobile phase consisting of Acetonitrile: 0.01% Orthophosphoric acid pH 2.5 at a flow rate of 1.0 ml/min. Detection wavelength was 210nm. The retention time of Entacapone was 7.0minutes. The developed method was validated in terms of specificity, forced degradation, linearity, precision, intermediate precision (ruggedness), accuracy, range and robustness. The calibration curve for Entacapone was linear (correlation coefficient 0.99995) from range of 50µg/ml to 150µg/ml. Relative standard deviation values for all the key parameters was less than 2.0%. The recovery of the Entacapone was found to be 100.3%. Thus, the developed RP-HPLC method was found to be suitable for the determination of Entacapone in bulk as well as stability samples of the pharmaceutical dosage forms containing various excipients.