Quantitation of Fansimef components (mefloquine + sulfadoxine + pyrimethamine) in human plasma by two high-performance liquid chromatographic methods.

Two simple, precise, and selective high-performance liquid chromatographic methods are described for the simultaneous quantitation of mefloquine (MQ) plus pyrimethamine (PYR) or sulfadoxine (SDX) plus its principal metabolite N4-acetylsulfadoxine (N4SDX) in human plasma. After a single-step extraction, MQ plus PYR and SDX plus N4SDX including internal standards were separated using ion-paired and ion-suppression chromatography. Total run times for the assays were less than 12 min. Intraassay and interassay precision of the methods expressed as the coefficients of variation were less than 9% in plasma for the four compounds. The extraction recovery averaged 98% for MQ, 97% for PYR, 96% for SDX, and 81% for N4SDX. Plasma concentrations of the four compounds in a pediatric patient after a single oral dose of Fansimef (MQ + SDX + PYR) were determined to demonstrate the clinical application of the methods.