Quantitative determination of vigabatrin and gabapentin in human serum by gas chromatography-mass spectrometry

Background: Published methods for routine clinical monitoring of vigabatrin and gabapentin are often very laborious. A simple GC-MS method was developed for the simultaneous quantitative determination of vigabatrin and gabapentin in human serum. Methods: After protein precipitation, the compounds are derivatized by methylation and analysed on a polydimethylsiloxane column using splitless injection. Cyclobarbital is used as the internal standard. To attain maximal sensitivity, detection is performed in selected ion monitoring mode. Results: The method was fully validated and linear calibration curves were obtained in the concentration ranges from 5 to 80 mu g/mL for vigabatrin and from 5 to 30 mu g/mL for gabapentin. The within-day and day-to-day relative standard deviations at three different concentration levels were < 10% and < 15%, respectively. The limit of quantitation was 2 mu g/mL for both compounds. Conclusions: The presented method provides high chromatographic resolution, good sensitivity and unequivocal identification potential and can be used for simultaneous analysis of both antiepileptics. (c) 2005 Elsevier B.V. All rights reserved.