Fluorimetric and spectrophotometric determination of ritodrine hydrochloride in bulk and pharmaceutical formulations

Two simple sensitive and accurate methods have been developed for the determination of ritodrine hydrochloride in bulk and pharmaceutical preparations. The first method involves the direct measurement of the native fluorescence of the drug in the concentration range 4-9 microg ml(-1), the second method is based on the oxidation of ritodrine HCl with cerium(IV) followed either by spectrophotometric or fluorimetric measurement in the concentration ranges 0.5-1.0 and 0.05-0.1 microg ml(-1), respectively. The interference of various formulation excipients was examined. The reliability of the proposed methods was checked at three different concentrations; the standard deviation varied from 2.7 x 10(-3)-0.109. The described methods have been applied to the determination of ritodrine HCl in tablets and ampoules. The assay results showed insignificant difference with those of the official USP 23 HPLC method.