Quantitative determination of Lisinopril Dihydrate in pharmaceutical preparations by direct potentiometriy

A direct potentiometric titration method was applied for determination of Lisinopril Dihydrate. The method was based on the treatment of the primary data with nonlinear regression procedure. An accessible and easy-to-use algorithm for the evaluation (quantification) of a system with acid-base properties has been developed to provide a quick and unambiguous answer for the quantitative content of Lisinopril Dihydrate. The acid-base constants of Lisinopril Dihydrate were determined in aqueous solutions (at constant ionic strength 0.2 mol/l KCl and temperature 25°C). The potentiometric method developed was validated according to ICH and shows very good accuracy and precision. The present approach can be successfully used in routine analysis of the drug in quality control laboratories.