SOLID-PHASE EXTRACTION AND RP-HPLC SCREENING ROCEDURE FOR DIURETICS,PROBENECID,CAFFEINE AND PEMOLINE IN URINE

A solid-phase extraction and reversed phase high performance liquidchromatographic method(RP-HPLC) was developed for the rapid determination of 13 diuretics (bel-onging to five different pharmacological groups) ,probenecid, caffeine and pemoline in urine. Two mlurine sample was first adsorbed on a XAD-2 column, then eluted with ether--ethyl acetate(l: 1).The eluate was evaporated to dryness and reconstituted in methanol. The methanolic solution wasinjected into a HP LiChrosorb RP-18 column, using phosphate buffer (pH 3) and acetonitrile as the mo-bile phase and monitored at 216 nm, 230 nm, and 275 nm on a diode array ultraviolet detector. Theextraction recoveries of 16 drugs were above 75%. The limits of detection ranged from 0. 3～3.0μg/ml of urine. All drugs were separately administered to healthy volunteers, positive urine sampleswere collected, and urinary excretion--time curves of some drugs were reported.