Determination of metoprolol in pure and pharmaceutical dosage forms by spectrofluorometry and high performance liquid chromatography

In this study, new and rapid spectrofluorometry and high performance liquid chromatography (HPLC) methods were developed for determination of metoprolol in pure and pharmaceutical dosage forms. The solvent system, wavelength of detection and chromatographic conditions were optimized in order to maximize the sensitivity of both proposed methods. The linearity was established over the concentration range of 50-4000 ng ml-1 for spectrofluorometry and 5.0-300 ng ml-1 for HPLC methods. The intra- and inter-day relative standard deviation (RSD) was less than 4.14 and 3.86% for spectrofluorometry and HPLC, respectively. The limit of quantitation was determined as 30 and 5.0 ng ml-1 for spectrofluorometry and HPLC, respectively. No interference was found from tablet excipients at the selected assay conditions. The methods were applied for the quality control of commercial metoprolol dosage forms to quantify the drug and to check the formulation content uniformity.