Premium
Simultaneous determination of leflunomide and its active metabolite, A77 1726, in human plasma by high‐performance liquid chromatography
Author(s) -
Schmidt Andreas,
Schwind Bianca,
Gillich Martin,
Brune Kay,
Hinz Burkhard
Publication year - 2003
Publication title -
biomedical chromatography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.4
H-Index - 65
eISSN - 1099-0801
pISSN - 0269-3879
DOI - 10.1002/bmc.244
Subject(s) - leflunomide , chemistry , metabolite , chromatography , high performance liquid chromatography , active metabolite , rheumatoid arthritis , medicine , biochemistry
The isoxazol derivative leflunomide [ N ‐(4′‐trifluoromethylphenyl)‐5‐methylisoxazole‐4‐carboxamide] is an inhibitor of de novo pyrimidine synthesis used for the treatment of rheumatoid artrithis. In the present study, a liquid–liquid extraction‐based reversed‐phase HPLC method with UV detection was validated and applied for the analysis of leflunomide and its active metabolite, A77 1726, in human plasma. The analytes were separated using a mobile phase, consisting of acetonitrile, water and formic acid (40/59.8/0.2, v/v), at a flow rate of 0.5 mL/min, and UV detection at 261 nm. The retention times for A77 1726, leflunomide and warfarin (internal standard) were 8.2, 16.2 and 12.2 min, respectively. The validated quantification range of the method was 0.05–100 µg/mL for leflunomide and 0.1–100 µg/mL for A77 1726. The developed procedure was applied to assess steady‐state plasma concentrations of A77 1726 in patients with rheumatoid arthritis treated with 10 or 20 mg leflunomide per day. Copyright © 2003 John Wiley & Sons, Ltd.