Detection of anticonvulsants and their metabolites in urine within a “general unknown” analysis procedure using computerized gas chromatography-mass spectrometry

Abstract

Detection of the anticonvulsants carbamazepine, clonazepam, diazepam, ethosuximide, mephenytoin, mesuximide, methylphenobarbital, phenobarbital, phenytoin, primidone, propylhexedrine, sultiame, trimethadion and their metabolites in urine is described. The method presented is integrated in a general screening procedure (general unknown analysis) for several groups of drugs, detecting several hundred drugs and over 1000 metabolites. It includes cleavage of conjugates by acid hydrolysis, isolation by liquid-liquid extraction, derivatization by acetylation, separation by capillary gas chromatography and identification by computerized mass spectrometry. Using mass chromatography with the selective ions m/z 58, 104, 113, 117, 165, 193, 204 and 246, the possible presence of anti-convulsants and/or their metabolites was indicated. The identity of positive signals in the reconstructed mass chromatograms was confirmed by a visual or computerized comparison of the stored full mass spectra with the reference spectra. The sample preparation, mass chromatograms, reference mass spectra and gas chromatographic retention indices are documented.

Modern Methods for Analysis of Antiepileptic Drugs in the Biological Fluids for Pharmacokinetics, Bioequivalence and Therapeutic Drug Monitoring

“…These systems, which need small volumes, are mainly based on commercial reagent-based immunoassay (FPIA or EMIT) techniques that represent the primary methodology for analysis PMD in serum [95,96]. Chromatographic methods involving GC and HPLC are nevertheless of importance when both the unchanged drug and its metabolites have to be quantified in plasma [97,98] or when the simultaneous determination of several AEDs is required [2,80] as well as in the toxicological or forensic analysis [99,100]. Because the targeted drugs are well known, methods based on HPLC and MS coupling should be available soon for the fast simultaneous determination of a greater numbers of AEDs.…”

Enantiospecific separation and quantitation of mephenytoin and its metabolites nirvanol and 4′‐hydroxymephenytoin in human plasma and urine by liquid chromatography/tandem mass spectrometry

“…However, there was no enantiomeric separation involved in these methods. Gas chromatographic methods with MS detection has been developed for the urinary determination of R ‐ and S ‐mephenytoin,22 separation of mephenytoin and 4′‐hydroxymephenytoin,23 quantitation of mephenytoin and its metabolites,16, 24 and for quantitation of the metabolites 2…”