Development of an ultra-performance liquid chromatography-tandem mass spectrometry micromethod for quantification of lamotrigine in human plasma and its use in a bioequivalence trial.

The aim of the present work was to develop a chromatographic technique coupled with mass spectrometry for the measurement of lamotrigine in plasma. Lamotrigine and guanabenz (internal standard) were measured by selected reaction monitoring. The method was validated and applied in a bioequivalence trial on 26 female volunteers. Lamotrigine chewable tablets (100 mg) were administered and monitored for up to 96 h. The method was linear between 0.05 and 5.0 µg/ml, with acceptable stability, accuracy and precision. Mean maximum plasma concentration was 1.37 µg/ml and was reached at 1.6 h postdose. Elimination half-life was 32.7 h. Lamotrigine tablets were bioequivalent. Ultra-performance liquid chromatography with tandem mass spectrometry represents a powerful tool in terms of sensitivity, specificity and high-throughput analysis.