Kinetic Spectrophotometric Determination of Ramipril in Commercial Dosage Forms

This paper presents a simple and sensitive kinetic spectrophotometric method for the determination of ramipril in commercial dosage forms. The method is based on the reaction of the drug with 1-chloro-2,4-dinitrobenzene (CDNB) in dimethylsulfoxide (DMSO) at 100 ± 1C. The reaction is followed spectrophotometrically by measuring the rate of change of the absorbance at 420 nm. Fixed-time (ΔA) and equilibrium methods are adopted for constructing the calibration curves. Both the calibration curves were found to be linear over the concentration ranges 20 220 μg/ml. The regression analysis of calibration data yielded the linear equations: Δ A = 6.30 × 10 + 1.54 × 10 C and A = 3.62 × 10 + 6.35 × 10 C for fixed time (Δ A) and equilibrium methods, respectively. The limits of detection (LOD) for fixed time and equilibrium methods are 1.47 and 1.05 μg/ml, respectively. The method has been successfully applied to the determination of ramipril in commercial dosage forms. Statistical comparison of the results shows that there is no significant difference between the proposed methods and Abdellatef’s spectrophotometric method. Keywords—Equilibrium method, Fixed-time (ΔA) method, Ramipril, Spectrophotometry.