1,2,4-Triazine derivative, its preparation and its use as reference marker for testing purity and stability of lamotrigine

摘要

A method of testing the purity or stability to degradation of a sample of lamotrigine or a pharmaceutical dosage form comprising lamotrigine comprises assaying the said sample for the presence of a compound selected from 3-amino-6-(2,3-dichlorophenyl)-1,2,4-triazine-5-(4H)-one (compound A) and N-Ä5-amino-6-(2,3-dichlorophenyl)-1,2,4-triazine-3-ylÜ-2,3-dichloroben zamide (compound B). A process for producing compound B, which is novel, is also disclosed.