Simultaneous determination of chloroquine, proguanil and their metabolites in human biological fluids by high-performance liquid chromatography.

A reversed-phase ion-pair high-performance liquid chromatographic method with ultraviolet detection is described for the simultaneous measurement of chloroquine, proguanil and their major metabolites in human plasma, erythrocytes and urine. After a liquid-solid extraction on a Bond Elut C8 cartridge, the compounds are separated on a C8 Lichrospher 60 RP select B column by isocratic elution; the mobile phase is water-acetonitrile-methanol (78:28:4, v/v/v) with 0.5 M ammonium formate and 0.075 M perchloric acid. The eluent is monitored with an ultraviolet detector at 254 nm. The lower limits of quantification in plasma are near 6.0 ng ml-1 for chloroquine and near 9.0 ng ml-1 for proguanil. No chromatographic interference can be detected from endogenous compounds or from other antimalarial drugs. The method is accurate and precision is good with inter- and intra-assay relative standard deviations lower than 6.8% for plasma samples. N-(2-6 dichlorobenzylidene amino)guanidine is used as an internal standard. The chromatographic procedure takes 35 min and can be used for therapeutic drug monitoring and clinical studies.

[Simple methods of chloroquine determination in urine and their adaptation in the field]. / Les méthodes simples de dosage de la chloroquine dans les urines et leur adaptation sur le terrain.

Field malaria studies require often the on site detection of chloroquine in urine for monitoring chemoprophylaxis and treatment compliance, investigating drug-use patterns and screening prospective subjects for in vitro and in vivo chemosensitivity tests. The field adapted methods are described, analytical characteristics are compared and different approaches to field adapted assay of chloroquine are discussed.

A photoinduced mixed-valence state in an organic bis-triarylamine mixed-valence compound with an iridium-metal-bridge.

Upon irradiation a mixed-valence (MV) state is formed in a donor-iridium(III)-acceptor triad by a photoinduced electron transfer process. The resulting radical and intervalence charge transfer (IV-CT) absorptions cover a wide spectral range (3200-400 nm). These results were supported by spectroelectrochemistry, fs-time resolved pump-probe spectroscopy and assisted by TD-DFT calculations.

Application of isoenzymatic typing to the identification of nonaxenic strains of Naegleria (Protozoa, Rhizopoda).

Isoenzymatic typing of the different species of Naegleria was studied by comparing isoelectric focusing on axenic and nonaxenic strains using the most discriminating enzymes: lactate dehydrogenase (LDH), malic enzyme (ME), beta-hydroxybutyrate dehydrogenase (beta-HBDH), superoxide dismutase (SOD), and acid phosphatase (AP). The results show that bacteria in nonaxenic cultures have no influence on the interpretation of zymograms. The specificity of the enzymatic patterns of each strain is maintained in all of these enzymatic systems except LDH. With SOD, the existence of a supplementary isoenzyme among all of the nonaxenic strains is probably linked to an enzymatic induction phenomenon.