[Development of an HPLC method for determination of chloroquine in plasma]

A simple, rapid and sensitive ion-pair high-performance liquid chromatographic method is described, which allows the quantification of chloroquine in human plasma. 7-Chloro-4-(4-ethylpropylamino-1-methyl-butylamino)quinoline was synthesized and used as internal standard. After extraction by toluene from 1 ml plasma, chloroquine was reextracted with 15% phosphoric acid from the organic phase. Chromatographic separation on a RP-18 column and UV-detection (343 nm) allows sensitive determination of chloroquine in plasma with a lower limit of quantification of 2.5 ng/ml. The method was successfully applied to human plasma samples from 16 subjects after oral administration of 250 mg chloroquine diphosphate.