SIMULTANEOUS DETERMINATION OF ARTESUNIC ACID AND DIHYDROARTEMISININ IN BLOOD-PLASMA BY HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY FOR APPLICATION IN CLINICAL PHARMACOLOGICAL STUDIES

A selective reproducible high-performance liquid chromatographic assay for the simultaneous quantitative determination of the antimalarial c ompound artesunic acid (ARS), dihydroartemisinin (DQHS) and artemisini n (QHS), as internal standard, is described. After extraction from pla sma, ARS and DQHS were analysed using an Econosil C-8 column and a mob ile phase of acetonitrile-0.05 M acetic acid (42:58, v/v) adjusted to pH 5.0 and electrochemical detection in the reductive mode. The mean r ecovery of ARS and DQHS over a concentration range of 50-200 ng/ml was 75.5% and 93.5%, respectively. The within-day coefficients of variati on were 4.2-7.4% for ARS and 2.6-4.9% for DQHS. The day-to-day coeffic ients of variation were 1.6-9.6% and 0.5-8.3%, respectively. The minim um detectable concentration for ARS and DQHS in plasma was 4.0 ng/ml f or both compounds. The method was found to be suitable for use in clin ical pharmacological studies.