Practical HPLC methods for the quantitative determination of common antimalarials in Africa

This article describes high-performance liquid chromatographic assays for the quantification of sulfadoxine (SDX), pyrimethamine (PYM), chloroquine (CQ), amodiaquine (AQ) and desethylamodiaquine (AQM) from whole blood. All four assays were set up and validated in Malawi using a common high-performance liquid chromatography platform and column and involved the use of simple mobile phase and extraction reagents. Calibration curves were linear (r2 > 0.95) in the ranges 5–100 μg/ml, 50–1000, 150–1500, 100–1000 and 100–1000 ng/ml for SDX, PYM, CQ, AQ and AQM, respectively. Intra-assay and inter-assay coefficients of variation were <15% at 3 points spanning the concentration range and <20% at the lower limit of quantification. The assays were specific with no interference from the other antimalarials described in this report. All four assays use liquid–liquid extraction, reversed-phase chromatography and UV detection and require between 50 and 200 μl of blood. Because the assays share common instruments and reagents, they are cost-efficient and could be used to optimise antimalarial drug therapies in other resource poor settings.