IDENTIFICATION OF METOCLOPRAMIDE METABOLITES IN THE URINE OF CATTLE BY GAS-CHROMATOGRAPHY MASS-SPECTROMETRY AND HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY PHOTODIODE-ARRAY DETECTION

The urinary metabolites of metoclopramide chloro-N-[2-diethylaminoethy l]-2-methoxybenzamide) were identified in cows. The drug was administe red intravenously, voided urine was collected, and individual urine ex tracts were analysed by ps chromatography-mass spectrometry and high-p erformance liquid chromatography-photodiode array detection. The paren t compound and one major metabolite chloro-N-[2-(ethylamino)ethyl]-2-m ethoxybenzamide) were common to all individuals. In addition to the pa rent and major metabolite, a second, minor metabolite was identified i n two cows as loro-N-[2-(diethylamino)ethyl]-2-hydroxybenzamide. The i dentity of the minor metabolite was confirmed by comparison with a sta ndard synthesized by a new method. Metabolite identification and chara cterization in food animal species allows the design of safety and env ironmental impact studies and relative metabolite ratios between dose treatment groups.