HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHIC ANALYSIS OF SELECTED SULFONAMIDES IN PLASMA

Chromatographic conditions were elaborated to evaluate a model mixture of four sulfonamides (sulfamethoxazole, sulfamoxole, sulfisoxazole an d sulfamethoxydiazine) in plasma using a reversed phase HPLC C-18 colu mn and a mobile phase composed of methanol and phosphate buffer (60:40 ; v/v) at pH 5.0. The detection was made using an electrochemical dete ction with the potential set at 1.1 V. In the case of sulfonamides dep roteination of plasma with methanol was more advantageous than extract ion with organic solvents. The recovery of analysed sulfonamides was i n the range of 95-97%, the detection limits were 10 ng/ml of plasma.