Enantioselective high-performance liquid chromatographic method for the determination of methadone and its main metabolite in urine using an AGP and a C8 column coupled serially

A simple and sensitive method for the enantioselective high-performance Liquid chromatographic determination of methadone and its main metabolite, EDDP, in human urine is described. (-)-(R)-Methadone, (+)-(S)-methadone, (+)-(R)-EDDP, (-)-(S)-EDDP and imipramine as an internal standard are detected by ultraviolet detection at 200 nn. The enantiomers of methadone and EDDP were extracted from human urine by a simple Liquid-Liquid extraction procedure. The extracted sample was reconstructed in mobile phase and the enantiomers of methadone and EDDP were quantitatively separated by HPLC on a short analytical LiChrospher RPs column coupled in series with a chiral AGP column. Determination of all four enantiomers was possible in the range of 0.03 to 2.5 mu M. The recoveries of methadone enantiomers and EDDP enantiomers added to human urine were about 90% and 80%, respectively. The method was applicable for determination of methadone enantiomers and the enantiomers of its main metabolite in urine samples from methadone maintenance patients and patients suffering from severe chronic pain. (C) 1999 Elsevier Science B.V. All rights reserved.