Quantitative analysis of Lamotrigine in plasma and tablets by planar chromatography and comparison with liquid

A method using planar chromatography (PC) was developed for determining lamotrigine (LTG; 3,5-diamino-6-[2,3-dichlorophenyl]-1,2,4-triazine) in human plasma and tablets. LTG was extracted with acetonitrile in the presence of sodium carbonate. 3,5-Diamino-6-(2-methoxyphenyl)-1,2,4-triazine was used as internal standard, The detection limit was 0.27 mu g/mL plasma and the recovery from human plasma fortified with various concentrations of LTG was 91.3 +/- 3.4%. Interference from other common antiepileptic agents was checked. Results obtained with the PC method were compared with those obtained by a method using liquid chromatography (LC) for analysis of plasma and with methods using LC and UV for assay of tablets.