Serum lamotrigine analysis by capillary electrophoresis

Lamotrigine, a new antiepileptic drug, is analyzed by capillary zone electrophoresis. Samples were deproteinized with acetonitrile containing an internal standard, acidified with dilute acetic acid and injected into the capillary. The drug migrated rapidly with the cationic compounds in about 3.5 min far from any interfering substances. The test was linear between 0.5-10 mg/l. The analysis time was about 5 min. The CE values correlated well with an HPLC method (r = 0.97; n = 35). The mean serum concentration of 121 patients on this drug was 3.7 mg/l. Incubating the serum with beta-glucuronidase for 1 h increased the peak height of lamotrigine by about 24%.