SPECTROPHOTOMETRIC SIMULTANEOUS DETERMINATION OF AMLODIPINE BESYLATE AND HYDROCHLOROTHIAZIDE IN COMBINED TABLET DOSAGE FORM BY SIMULTANEOUS EQUATION, ABSORPTION RATIO AND FIRST ORDER DERIVATIVE SPECTROSCOPY METHODS
Keywords:Amlodipine, Hydrochlorothiazide, simultaneous estimation, validation
Three sensitive, precise, accurate and simple UV spectrophotometric methods have been developed for simultaneous estimation of Amlodipine
(AMLO) and Hydrochlorothiazide (HCT) in tablet dosage forms. Method A involved simultaneous equation method. The two wavelengths 238.5 nm
(λmax of AMLO) and 271 nm (λmax of HCT) were selected for the formation of Simultaneous equations. Whereas method B involved formation of Q‐
absorbance equation at isobestic point (257.5 nm). Method C is First order Derivative Spectroscopy method in which derivative amplitudes were
measured at selected wavelengths (238.5 nm for HCT and 271 nm for AMLO). Linearity was observed in the concentration range of 1‐10, 1‐20,1‐20
mcg/ml for AMLO and 2.5‐25, 2.5‐50, 2.5‐50 mcg/ml for HCT by method A, B and C respectively. The proposed methods have been applied
successfully to the analysis of cited drugs in pharmaceutical formulations. Recovery study was performed to confirm the accuracy of the methods.
The methods were validated as per ICH guidelines.