Spectrofluorometric Determination of Lisinopril dihydrate and Methyl- Dopa in Bulk and Pharmaceutical Formulation by Using Dansyl Chloride

A novel spectrofluorometric method has been developed for quantitative determination of Lisinopril dihydrate and methyldopa either in pure form or in pharmaceutical preparation. The principle of the method based on the reaction of each drug with dansyl chloride [5-(Dimethyl Amino) Naphthalene-1-Sulfonyl chloride] by the aid of sodium hydroxide solution of pH 8.5 resulted in a product of a high fluorescent intensity which was then measured at 511 nm and 516 nm, for lisinopril and methyldopa respectively after excitation at 323 nm. Factors affecting reaction development were studied and optimized. The proposed method was found to be sensitive, selective and reproducible. Calibration curves were linear over the concentration ranges of 3–20 for lisinopril and 7–25 μg/mL for methyldopa. Results obtained from tablets analysis were compared statistically with reported reference methods.