Measurement of physiological concentrations of dapsone and its monoacetyl metabolite: A miniaturised assay for liquid or filter paper-absorbed samples

A modification of existing HPLC assay methods is described for the measurement of dapsone and monoacetyldapsone in 50-mu l samples of plasma and whole blood. This method, in particular the use of small sample volumes dried onto filter paper strips, is applicable to multi-sample clinical and pharmacokinetic studies in children with malaria, who are often anaemic, and where sample volume must be kept to a minimum. Basified samples were extracted into 5 mi of ethyl acetate-tert.-butylmethyl ether(1:1, v/v), chromatographed on a mu BondapaK C-18 10-mu m column with water-acetonitrile-glacial acetic acid (81:17.5:5, v/v) containing 2 g/l 1-octanesulphonic acid as the mobile phase and detected at 274 nm