Schrader E, Klaunick G, Jorritsma U, Neurath H, Hirsch-Ernst K I, Kahl G F, Foth H
Department of Toxicology, Institute of Pharmacology and Toxicology, University of Göttingen, Germany.
J Chromatogr B Biomed Sci Appl. 1999 Apr 16;726(1-2):195-201. doi: 10.1016/s0378-4347(99)00040-7.
A selective and sensitive reversed-phase liquid chromatographic method was developed for the simultaneous analysis of [1-Me-14C]caffeine and its eight major radiolabelled metabolites in rat urine. The separation of the complex mixture of caffeine metabolites was achieved by gradient elution with a dual solvent system using an endcapped C18 reversed-phase column, which in contrast to commonly used C18 reversed-phase columns also allows the separation of the two isomers of 6-amino-5-(N-formylmethylamino)-1,3-dimethyluracil (1,3,7-DAU), a caffeine metabolite of quantitative importance predominantly occurring in rat. As caffeine is metabolised primarily by members of the cytochrome P450 1A (CYP1A) subfamiliy, determination of the pattern of caffeine metabolites in rat urine enables analysis of activities of this important enzyme subfamily in vivo. Since CYP1A is suggested to be involved in the detoxification of bilirubin, the assay may be applied to search for untoxic inducers of CYP1A which might be of pharmacological interest in the treatment of hyperbilirubinaemia.
建立了一种选择性和灵敏的反相液相色谱法，用于同时分析大鼠尿液中的[1-Me-14C]咖啡因及其八种主要放射性标记代谢物。使用封端的C18反相柱，通过双溶剂系统梯度洗脱实现咖啡因代谢物复杂混合物的分离，与常用的C18反相柱相比，该柱还能分离6-氨基-5-(N-甲酰基甲基氨基)-1,3-二甲基尿嘧啶（1,3,7-DAU）的两种异构体，1,3,7-DAU是咖啡因的一种代谢物，在大鼠体内主要以定量形式存在。由于咖啡因主要由细胞色素P450 1A（CYP1A）亚家族成员代谢，测定大鼠尿液中咖啡因代谢物的模式能够分析该重要酶亚家族在体内的活性。由于CYP1A被认为参与胆红素的解毒，该测定法可用于寻找CYP1A的无毒诱导剂，这可能在高胆红素血症治疗中具有药理学意义。
