Discrepancy in plasma melarsoprol concentrations between HPLC and bioassay methods in patients with T. gambiense sleeping sickness indicates that melarsoprol is metabolized.

OBJECTIVE: With the use of a specific high-performance liquid chromatography (HPLC) method and a bioassay which determines trypanocidal activity, concentrations of melarsoprol were assessed in plasma, urine and cerebrospinal fluid (CSF) from 8 patients with late-stage Trypanosoma gambiense sleeping sickness. The aim was to unravel to what extent the bioassay codetermines biologically active metabolites of melarsoprol. METHODS: Subjects were given one dose of melarsoprol i.v. per day for 4 days (1.2, 2.4, 3.0-3.6, 3.0-3.6 mg per kg b.w., respectively). Plasma samples were obtained before the first melarsoprol injection, immediately after and at 1 h, 24 h and 5 days after the 4th injection. Urine was collected before melarsoprol therapy and at 24 h after the 4th injection. CSF samples were taken once before treatment and at 24 h after the 4th injection. RESULTS: HPLC analyses showed that plasma concentrations immediately after the 4th injection varied from 2200 to 15,900 nmol/l; dropping to 0-1800 nmol/l at 1 h; and to undetectable levels at 24 h. In urine small amounts of melarsoprol were recovered. Melarsoprol could not be detected in CSF by HPLC. Immediately after injection, bioassay analyses showed plasma concentrations of the same magnitude as HPLC assays but at 1 h they were 4-65-fold higher than the levels assessed by HPLC. Even 24 h and 5 days after the 4th injection there was significant but decreasing activity. Urine levels were 40-260-fold higher than the measured HPLC concentrations, whereas there was low but detectable activity in CSF. CONCLUSION: Results indicate that melarsoprol is rapidly eliminated from plasma. The significant trypanocidal activity determined by bioassay and simultaneous low or undetectable levels of melarsoprol assayed by HPLC indicate that the compound is transformed into metabolites with parasiticidal activity.

[The different present-day clinical picture of human African trypanosomiasis caused by T. b. gambiense. Analysis of 300 cases from a focus in Daloa, Ivory Coast]. / Les différents tableaux cliniques actuels de la trypanosomiase humaine africaine à T. b. gambiense. Analyse de 300 dossiers du foyer de Daloa, Côte-d'Ivoire.

300 patients with sleeping sickness have been admitted, at the AHT clinic of Daloa, over a time period of 22 months. The sex ratio of the patients is 1.5 males for 1 female; the mean age is 25.5 years. The most frequent signs and symptoms observed by clinical examination are: fever (30%), nodes (86.3%), prurigo (43.3%), splenomegaly (15.3%), hepatomegaly (1%), headache (72.6%), vigilance and sleeping disturbances (68.7%), perioral reflexes (67.6%), cheiro-oral reflexes (64.3%), movement disorders consisting of tremor, choreo-athetosis movements, buccal dyskinesia or seizures (35%), motor palsy and gait disorders (15%), tonus disturbances (12.3%), sensitivity abnormalities (17%), endocrine disorders (16.3%), psychiatric symptoms (6.3%). According to CSF status, 261 patients have been classified in second period (P2). This group, although biologically well defined, is in fact a miscellaneous group of clinical signs and symptoms ranging from apparently normal patients to sleeping comatose and cachectic patients. 93% of the patients in this group have peripheral signs associated with neurological symptoms. They are as frequent in the first period as in the second period, with a statistical significance. This is an argument to think that the CNS is early affected in the course of the disease. The classification of the patients in groups of increasing neurological impairments, is in accordance with this hypothesis. 89% of the patients in the second period have only slight neurological signs. This explain how difficult it is for a physician to use melarsoprol in the treatment of all patients classified in second period.