HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY DETERMINATION OF DAPSONE, MONOACETYLDAPSONE, AND PYRIMETHAMINE IN FILTER-PAPER BLOOD SPOTS

A high-performance liquid chromatography method for the simultaneous a nalysis of dapsone (DDS), the major metabolite of DDS, monoacetyldapso ne (MADDS), and pyrimethamine (PYR) was modified for capillary blood s amples obtained by finger prick and dried on filter paper. Limit of qu antitation using 150 mu l whole blood dried on filter paper was found to be 20 ng/ml for DDS and PYR and 15 ng/ml for MADDS (precision <15%) . The clinically relevant concentrations of DDS are 50-2,000 ng/ml and for PYR 25-150 ng/ml. No interference from several drugs were observe d. The accuracy of the filter paper method and the original whole-bloo d method was almost comparable. Standardization could therefore be obt ained by the more simple whole-blood method. Dried filter paper sample s stored at 19-22 degrees C were stable for months and for 2 weeks sto red at 35 degrees C. The concentrations of simultaneously collected ca pillary blood and conventional venous blood samples correlated well. T he present method using capillary blood dried on filter paper is relia ble, simple, sensitive, and applicable in the field with limited techn ical facilities.