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.