1. Azopigments derived from conjugated bile pigments by coupling with the diazonium salt of ethyl anthranilate are analysed conveniently by quantitative t.l.c. or by column chromatography on CM-cellulose. 2. By chromatographic studies combined with a series of chemical tests six groups of azopigments were demonstrable in preparations from bile and from icteric urine of man. Azobilirubin and its β-d-monoglucuronide have hitherto been considered to be the only major derivatives that can be obtained from human bile pigments. In the present work, other azopigments accounted for 30–40% of the total azopigment material, and the amounts of these showed considerable variation among biological fluids. 3. The divergence of the present results from earlier work is probably related to the use of milder diazotization conditions and of chromatographic techniques with a high resolving power. 4. The thin-layer chromatographic systems developed allow rapid and quantitative analysis of azopigments derived from bile pigments.

Background: The efficacy of artemisinin-based combination therapy has already been demonstrated in a number of studies all over the world, and some of them can be regarded as comparably effective. Ease of administration of anti-malarial treatments with shorter courses and fewer tablets may be key determinant of compliance.

The structures of some azopigments obtained by diazotization of conjugated and unconjugated bile pigments with diazotized ethyl anthranilate were studied by mass spectrometry. The oco-azopigments derived from rat bile and human bile were shown to be identical (t.l.c. and mass spectra) with azobilirubin derived from unconjugated bilirubin. The presence of two methyl vinyl isomers (Ia) and (Ib) in equal amounts was shown by t.l.c. and mass spectrometry. The structure of the 8-azopigment derived from rat bile was studied by two methods: (a) ammonolysis gave rise to an amide having a CH2 * CH2 * CO * NH2 side chain as shown by its mass spectrum; (b) the mass spectrum of a trimethylsilyl derivative of the 8-azopigment methyl ester confirmed the ester to be a f-D-monoglucuronide ester ofazobilirubin I.

In the 2010 second edition of WHO's guidelines for the treatment of malaria, the relatively new fixed dose combination dihydroartemisinin-piperaquine is included as one of the recommended artemisinin combination therapies. However, experimental testing demonstrates that, due to its intrinsic chemical instability, dihydroartemisinin is not suitable to be used in pharmaceutical formulations. In addition, data show that the currently available dihydroartemisinin preparations fail to meet the internationally accepted stability requirements. At a time when many efforts aim to ban counterfeit and substandard drugs from the malaria market, the obvious question rises how WHO and public-private partnerships, such as Medicine for Malaria venture (MMV), can support the production and marketing of anti-malarial drugs that do not even meet the International Pharmacopoeia requirements?

Although artemisinin and its derivatives are widely used for the treatment of malaria, they also have antischistosomal activity. In a small study in eastern Sudan, the effects of the treatment of uncomplicated, Plasmodium falciparum malaria with artesunate-sulfamethoxypyrazine-pyrimethamine (AS-SMP) and artemether-lumefantrine (AT-LU) on co-infections with Schistosoma mansoni were therefore investigated. Faecal samples from 14 of the 306 patients screened on presentation, at the start of a clinical trial of antimalarial treatment, were found to contain Schistosoma mansoni eggs. For the treatment of their malaria, the 14 egg-positive cases, who were aged 6-40 years (mean = 13.7 years), were each subsequently treated with three tablets of a fixed combination of AS-SMP, with a 12-h (six patients) or 24-h interval (five patients) between each tablet, or with six doses of AT-LU given over 3 days. When checked 28 and 29 days after the initiation of treatment, all 14 patients were found stool-negative for schistosome eggs. These results indicate that AS-SMP and AT-LU are currently very effective treatments not only for uncomplicated, P. falciparum malaria but also for S. mansoni infections.