Stereoselective screening for and confirmation of urinary enantiomers of amphetamine, methamphetamine, designer drugs, methadone and selected metabolites by capillary electrophoresis

Data presented in this paper demonstrate that a competitive binding, electr okinetic capillary-based immunoassay previously used for screening of urina ry amphetamine and analogs cannot be employed to distinguish between the en antiomers of amphetamine and methamphetamine. However, capillary zone elect rophoresis with a pH 2.5 buffer containing (2-hydroxypropyl)-beta-cyclodext rin as chiral selector is shown to permit the enantioselective analysis of urinary extracts containing methamphetamine, amphetamine, 3,4-methylenediox ymethamphetamine (Ecstasy) and other designer drugs, and methadone together with its major metabolite, 2-ethylidene-1,5-dimethyl-3,3-diphenylpyrrolidi ne. In that approach, enantiomer identification is based upon comparison of extracted polychrome UV absorption data and electropherograms obtained by rerunning of spiked extracts with spectra and electropherograms monitored a fter extraction of fortified blank urine. The suitability of the described chiral electrokinetic capillary method for drug screening and confirmation is demonstrated via analysis of unhydrolyzed quality control urines contain ing a variety of drugs of abuse. Furthermore, in a urine of a patient under selegiline pharmacotherapy, the presence of the R-(-)-enantiomers of metha mphetamine and amphetamine could be unambiguously identified. Direct intake of an R-enantiomer or ingestion of drugs that metabolize to the R-enantiom ers can be distinguished from the intake of S-(+)-enantiomers (drug abuse) or prescribed drugs that metabolize to the S-enantiomers of methamphetamine and amphetamine. The described approach is simple, reproducible, inexpensi ve and reliable (free of interferences of other major basic drugs that are frequently found in toxicological urines) and could thus be used for screen ing for and confirmation of urinary enantiomers in a routine laboratory.