In rural tropical areas, patients frequently present with malaria and require urgent therapy. Facilities may not exist for parenteral drug administration, and oral dosing is precluded by obtundation or vomiting. In these circumstances, the rectal route of administration may allow initiation of antimalarial therapy while patients await transfer to hospital, a process that may take many hours.Artesunate (ARS) is a water-soluble hemisuccinate dihydroartemisinin (DHA) derivative being developed for the treatment of malaria and is particularly valuable against multidrugresistant infections (2, 13). ARS is currently formulated for administration by the oral and parenteral routes (3, 11). ARS suppositories (Rectocaps; 50 mg of artesunate; Mepha Pharmaceuticals Ltd.) Aesch-Basle, Switzerland) have recently undergone preliminary assessment in Gabonese children (8). However, formal bioavailability studies with this formulation are lacking. Circulating ARS is quickly converted to DHA by blood esterases and hepatic metabolism (14). As DHA is the principal antimalarial metabolite of ARS, the bioavailability of DHA was studied by comparing intrarectally (i.r.) and intravenously (i.v.) administered ARS in Ghanaian children with moderate malaria. High-performance liquid chromatography (HPLC) with electrochemical detection, currently the most precise and sensitive assay, was used to measure ARS and DHA levels. This crossover study was also designed to test the hypothesis that within the first 24 h there is no disease effect on the pharmacokinetics of ARS. These studies are critical to the design of larger (phase III-IV) studies seeking to use rectal ARS to reduce mortality from malaria.
MATERIALS AND METHODS
Study design description.This was an open, randomized, crossover comparison between i.v. ARS and ARS suppositories conducted on a pediatric research ward at Komfo-Anokye Teaching Hospital, Kumasi, Ghana, from August to October 1996. This study was approved by The Committee of Research, Publication and Ethics of the School of Medical Sciences, University of Science and Technology, Kumasi, Ghana, and the Review Board of the World Health Organization. A computer-generated randomization list allocating patients to one of three treatment categories was prepared (in permuted blocks of 12 patients). The treatment category for each patient was provided in an opaque sealed envelope opened only when a patient entered the study. Treatment categories were as follows: group I, i.r. ARS at 10 mg/kg of body weight, followed 12 h later by i.v. ARS at 2.4 mg/kg; group II, i.r. ARS at 20 mg/kg, followed 12 h later by i.v. ARS at 2.4 mg/kg; and group III, i.v. ARS at 2.4 mg/kg, followed 12 h later by i.r. ARS at 20 mg/kg. The doses of i.r. ARS were based on preliminary pharmacodynamic analysis of a similar study of i.r. ARS in Thai adults with moderate malaria (S. Looareesuwan, personal communication).Inclusion criteria. Patients aged 18 months to 7 years (inclusive) with a diagnosis of moderate Plasmodium falciparum malaria were eligible, pro...
