Kinetic spectrophotometric method for determination of lisinopril in bulk material and tablets using alkaline potassium permanganateAuthor(s): Nasr Y.Khalil
A simple and sensitive kinetic spectrophotometric method has been developed and validated for the determination Lisinopril in bulk drug and in its pharmaceutical tablets. Themethod was based on the oxidation of lisinopril (LSP) with alkaline potassium permanganate resulting in a green colored reaction product. The reaction was monitored spectrophotometrically by measuring the absorbance of the reaction product at 610 nm. The factors affecting the reaction were studied and optimized. The stoichiometry of the reaction was determined and the reaction pathway was postulated. The activation energy of the reaction was calculated and found to be 29 k joule mole-1. The initial rate and the fixed time methods were used for constructing the calibration graphs. The analytical performance of bothmethods was validated, and the results were satisfactory, however, the fixed time method was superior. The method was directly applied to the determination of LSP in bulk drug and by standard additionmethod in its commercial pharmaceutical tablets. Themean tablet label claimpercentage was found to be 100.2 ï± 0.25 (n=4). Statistical comparison of the results with those obtained by a reference method showed excellent agreement between the accuracy and precision of the two methods. The proposed method has a great value in its application to the analysis of LSP in quality control laboratories.