Abstract
Leflunomide was found to be metabolized predominantly to A77-1726 and two novel hydroxylated metabolites, M1 and M2, in microsomes while A77-1726 was only biotransformed to M1. M1 and M2 were proposed to be the hydroxylated α-cyanoenol form of A77-1726 and the hydroxylated 5 methyl-isoxazole form of leflunomide, respectively.
Keywords: Leflunomide, A77-1726, microsomes, metabolic profiling, UPLC, QTOFMS