Determination of lisinopril in pharmaceuticals by a kinetic spectrophotometric method

A kinetic spectrophotometric method for determination of lisinopril in pharmaceuticals has been developed. The method is based on activator action of lisinopril on Cu(II) ions catalysing the oxidation of nile blue A with hydrogen peroxide in borate buffer (pH 9.3). A decrease of the absorbance was recorded at 635 nm for 5 min at 25?C. The linearity was established applying the tangent method within the concentration range of lisinopril from 0.8-6.4 ?g mL-1, the detection and quantification limits being 0.158 ?g mL-1 and 0.480 ?g mL-1, respectively. The method has been successfully applied in three brands of tablets containing lisinopril alone or in combination with hydrochlorothiazide. nema