Rudolf J, Blaschke G
Department of Pharmaceutical Chemistry, University of Münster, Germany.
Enantiomer. 1999;4(3-4):317-23.
Two capillary electrophoretic (CE) methods for the determination of conjugated metabolites of the antihistaminic drug dimethindene were developed. These methods allow the determination of the diastereomeric ratios of both Phase II glucuronides, 6-hydroxy dimethindene glucuronide (5) and 6-hydroxy-N-demethyl dimethindene glucuronide (6). Furthermore, after enzymatic deconjugation of both glucuronides, enantiomeric ratios of the hydroxylated Phase I metabolites 3 and 4 were determined. For comparison, glucuronides 5 and 6 were prepared by enzymatic synthesis and identified by MALDI-TOF mass spectrometry and deconjugation with beta-glucuronidase to the corresponding phenols 3 and 4. The assay of the glucuronides in rat urine and serum was performed by a combination of liquid/liquid extraction followed by solid phase extraction. After a high dose treatment with racemic dimethindene the diastereomeric glucuronides 5 and 6 could be directly determined in the urine of a guinea pig by CE without prior extraction or preconcentration of the urine sample. In all cases, stereoselectivities of the formation of Phase I as well as Phase II metabolites were observed.
开发了两种毛细管电泳（CE）方法用于测定抗组胺药二甲茚定的共轭代谢物。这些方法能够测定两种II相葡糖醛酸苷，即6-羟基二甲茚定葡糖醛酸苷（5）和6-羟基-N-去甲基二甲茚定葡糖醛酸苷（6）的非对映体比例。此外，在对两种葡糖醛酸苷进行酶促去共轭后，测定了羟基化I相代谢物3和4的对映体比例。作为比较，通过酶促合成制备了葡糖醛酸苷5和6，并通过基质辅助激光解吸电离飞行时间质谱（MALDI-TOF MS）以及用β-葡糖醛酸苷酶将其去共轭为相应的酚3和4进行鉴定。大鼠尿液和血清中葡糖醛酸苷的测定通过液-液萃取后再进行固相萃取的组合方法进行。在用外消旋二甲茚定进行高剂量治疗后，豚鼠尿液中的非对映体葡糖醛酸苷5和6无需预先对尿液样品进行萃取或预浓缩即可通过CE直接测定。在所有情况下，均观察到了I相和II相代谢物形成的立体选择性。
