HPLC-NMR IDENTIFICATION OF THE HUMAN URINARY METABOLITES OF -[2-(HYDROXYMETHYL)-1,3-OXATHIOLAN-5-YL]-CYTOSINE, A NUCLEOSIDE ANALOG ACTIVE AGAINST HUMAN-IMMUNODEFICIENCY-VIRUS (HIV)

1. Human urine samples from a clinical trial of the anti-HIV compound -1-[2-(hydroxymethl)-1,3-oxathiolan-5-yl]-cytosine (BW524W91) have bee n analysed using F-19-nmr and H-1-hplc-nmr spectroscopy. 2. The identi ties and relative levels of the xenobiotic species in the urine have b een determined by 470-MHz F-19-nmr spectroscopy and by directly couple d 600-MHz H-1-hplc-nmr in the stop-flow mode with confirmation of the metabolite identities being made by comparison with nmr spectra of syn thetic standard compounds. 3. The principal urinary xenobiotic was the unchanged drug, but the glucuronide ether conjugate at the 5' positio n of BW524W91, one of the two diastereomeric sulphoxides and the deami nated metabolite were also characterized. 4. The detection limit of di rectly coupled hplc-600-MHz H-1-nmr spectroscopy was evaluated by meas uring two-dimensional nmr spectra of the glucuronide conjugate of BW52 4W91 and shown to be approximately 1 mu g material for H-1-H-1-TOCSY a nd 20 mu g metabolite for H-1-C-13-HMQC spectra for overnight (16 h) a cquisition.