Simultaneous determination of chloroquine and metronidazole in human biological fluid by high pressure liquid chromatography.

Chloroquine (CQ) and metronidazole (MZ) were measured in human urine and plasma by HPLC with UV detection. This method was used to analyse plasma levels in 4 African volunteers after an oral dose of 1000 mg CQ and 750 mg MZ, in a European on weekly prophylaxis of 500 mg CQ, and on 50 hospital urine samples. In the Africans peak plasma levels were over 1 microgram/ml and peak time was 1 1/2-2 hr. In the European plasma levels ranged from 0.58 to 0.36 microgram/ml. Over 80% of the urine samples contained CQ, MZ or both. The assay system was found flexible and economical for the therapeutic monitoring of these two important tropical drugs.