SIMULTANEOUS EQUATION METHOD AND ABSORPTION CORRECTION METHOD FOR THE ESTIMATION OF PERINDOPRIL ERBUMINE AND AMLODIPINE BESYLATE IN BULK AND IN COMBINED TABLET DOSAGE FORM USING UV SPECTOPHOTOMETRY

In the present work a simple, accurate and precise method has been developed and validated for the simultaneous estimation of Perindopril Erbumine (PDE), Amlodipine Besylate (AMD)and in their combined dosage form by UV Spectrophotometric Methods. The Method A employs estimation of drugs by simultaneous equation method (SEM) using 298.3 nm and 231.9nm i.e. λmax values of PDE and AMD respectively. Method B employs the estimation of drugs by Absorption Correction method (ACM) at 250.4nm for PDE where absorbance of AMD is zero. Absorbance correction method was based on the property of additivity of absorbances. At 250nm, Perindopril erbumine showed some absorbance while Amlodipine besylate showed zero absorbance. The method involved measurement of absorbance at two wavelengths 250 and 231 nm. For estimation of AMD, corrected absorbance was calculated at 231 nm due to the interference of PDE at this wavelength. Calibration curves were linear with correlation coefficient between 0.999 over the concentration range of 10-150μg/mL and 0.5-10 μg/mL for PDE and AMD respectively. The percent recoveries of the drugs were found nearly 100 % representing the accuracy of the both methods. Validation of the proposed methods was carried out for its accuracy, precision, specificity, linearity and limit of detection according to ICH guidelines. The proposed methods can be successfully applied in routine work for the determination of perindopril and amlodipine in combined dosage form.