Failure to detect amodiaquine in the blood after oral administration.

Plasma and red blood cell concentrations of amodiaquine (AM) and its metabolite, desethylamodiaquine (DAM), were monitored at intervals up to 21 days after a single oral dose of 600 mg amodiaquine in five normal African subjects. Concentrations of AM and DAM were determined using a high performance liquid chromatography technique with a lower limit of sensitivity of 10 ng ml-1 for both compounds. AM was not detectable in plasma and red blood cell samples withdrawn from any of the subjects. DAM was detectable in both media. It appeared in the blood 0.5-1 h after administering AM, reached a peak in 1.5-2 h and subsequently declined slowly. We conclude that AM is rapidly converted to DAM and its blood concentration, compared with that of DAM, is very low if not negligible.