Determination of Pipemidic Acid in Urine by High Performance Liquid Chromatography and Its Pharmacokinetics

A high performance liquid chromatography (HPLC) was used for the determination of urinary pipemidic acid (PPA). PPA was chromatographed as ion pairs with ethanesulphonic acid by use of Finepack SIL C18-10 reverse phase column. The amount of PPA was determined by the peak height ratio. The coefficients of variation at within-run were 1.77%(50 μg/ml) and 2.83%(1200 μg/ml), and at between-run were 8.77%(50 μg/ml) and 3.34%(1200 μg/ml). The urinary levels of PPA after oral administration of 500 mg to healthy male subjects were measured and pharmacokinetics of PPA were studied. The mean elimination rate constant (ke) was 0.27±0. 02 h-1, biological half-life (t1/2) was 2.6±0.16 h, and the maximal time of the elimination rate (Tmax) was 2.5±1 h. It was confirmed that the urinary levels of PPA determined by this method agree well with those by bioassay.