The use of on-line high-performance liquid chromatography-mass spectrometry for the identification of ranitidine and its metabolites in urine

Abstract

1. Reverse and normal phase h.p.l.c. systems have been developed for separation of ranitidine and three metabolites, desmethylranitidine, ranitidine-S-oxide and ranitidine-N-oxide. 2. These h.p.l.c. systems have been evaluated for characterization of ranitidine and metabolites using an h.p.l.c. coupled to a mass spectrometer with a moving belt interface. 3. Ranitidine and its metabolites were thermally degraded under the conditions required to evaporate the reverse phase eluent that contained 40% aq. 0.05 M ammonium acetate. 4. The normal phase eluent was evaporated in the interface at a lower temp, and satisfactory mass spectra were obtained from 1 μg of ranitidine and each metabolite injected on to the h.p.l.c. column. 5. Normal phase h.p.l.c.-mass spectrometry has been used to identify ranitidine and three of its metabolites in rabbit and human urine obtained after oral administration of ranitidine.