Determination of reserpine and hydrochlorothiazide in commercial tablets by liquid chromatography with fluorescence and UV absorption detectors in series.

A procedure is presented for the determination of reserpine and hydrochlorothiazide in commercial tablets by liquid chromatography (LC). Reference and sample solutions are prepared in methanol. For LC, a normal phase column is used, methanol is the eluting solvent, and 2 detectors are arranged in series. A fluorescence detector set at an excitation wavelength of 280 nm and emission wavelength of 360 nm quantitates reserpine, and a UV absorption detector set at 345 nm determines hydrochlorothiazide. Several synthetic mixtures containing the 2 ingredients in the amounts approximately present in commercial tablets were analyzed by the proposed method. Two samples of commercial tablets were also analyzed; for each sample, 5 determinations were made on a ground composite of 20 tablets; 10 individual tablets were also analyzed. For comparison, some of the solutions were analyzed for each ingredient by an alternative procedure.