A novel sensitive and cost-effective spectrofluorimetric method has been developed and validated for determination of lisinopril (an angiotensin converting enzyme inhibitor) in its pure form and pharmaceutical preparations. The method is based on the reaction of the drug with ninhydrin and phenylacetaldehyde in buffered medium (pH 7.0) to form a highly fluorescent product measured at 460 nm after excitation at 390 nm. Different experimental parameters were optimized and calibration curve was constructed. The fluorescence-concentration relationship was linear in the range of 0.15-4.0 μg mL-1 . The calculated Limit of detection (LOD) and Limit of quantitation (LOQ) were 0.04 and 0.12 μg mL-1 , respectively. The method was successfully applied for the analysis of pharmaceutical preparations containing the studied drug either alone or co-formulated with hydrochlorothiazide. The obtained results were in agreement with those of the reported method in respect to accuracy and precession. Moreover, the method was applied content uniformity testing according to United States Pharmacopeia (USP) guidelines.
Keywords: lisinopril; ninhydrin; pharmaceutical analysis; spectrofluorimetry.
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