Kinetic spectrophotometric method for the determination of perindopril erbumine in pure and commercial dosage forms

A kinetic spectrophotometric method has been developed for the determination of perindopril erbumine in pure and commercial dosage forms. The method is based on the reaction of drug with potassium permanganate in alkaline medium at room temperature (30±1°C). The reaction was followed spectrophotometrically by measuring the increase in absorbance with time at 603nm and the initial rate, fixed time (at 8.0min) and equilibrium time (at 90.0min) methods were adopted for constructing the calibration graphs. All the calibration graphs are linear in the concentration range of 5.0–50.0μg/ml. The limits of detection for initial rate, fixed time and equilibrium time methods were 0.752, 0.882 and 1.091μg/ml, respectively. The activation parameters such as Ea, ΔH‡, ΔS‡ and ΔG‡ were also determined for the reaction and found to be 60.93kJ/mol, 56.45kJ/mol, 74.16J/Kmol and −6.53kJ/mol, respectively. The variables were optimized and the proposed methods are validated as per ICH guidelines. The method has been further applied to the determination of perindopril erbumine in commercial dosage forms. The analytical results of the proposed methods when compared with those of the reference method show no significant difference in accuracy and precision and have acceptable bias.