[Temporary evolutions of flies anopheles in high altitude region of Lwiro-Katana (Democratic Republic of the Congo)]. / Évolution temporelle des captures d'anophèles en région d'altitude de Lwiro-Katana (République démocratique du Congo).

This study has been done with the objective of knowing more about the Anopheles evolutions situation at Lwiro-Katana from 1967 up to 2014. On seven species identified in this region, only four were permanent in nine investigations done. The geometric average calculated shows the evolution of 3.152 for Anopheles funestus, 2.867 for An. gambiae, 2.663 for An. demeilloni and 2.441 for An. marshallii. These species share almost the same ecological conditions for their larval development found in different kinds of water. These conditions were created by the anthropisation of the region followed by some activities. The increasing process attests that An. funestus, An. gambiae and An. demeilloni have an increasing tendency while An. marshallii has a decreasing tendency and is likely to approach the 0 level. An. coustani and An. christyi miss the stability development due to the environmental pertubations since 1980 in this environment. An. kingi wasn't identified after 1980. All of these species of anopheles share the same ecological niche and present a scientific interest. The knowledge of their evolution in this area is really very important because it helps to have better vector control. Also three of those mosquitos (An. gambiae, An. funestus and An. marshallii) are the greatest responsible of the killing paludism South of the Sahara.

A fast and sensitive method for quantifying lumefantrine and desbutyl-lumefantrine using LC-MS/MS.

A sensitive liquid chromatography tandem mass spectrometry (LC-MS/MS) method was developed for quantification of lumefantrine (LUM) and its metabolite desbutyl-lumefantrine (DBL) in human plasma. Sample preparation was done by protein precipitation using acetonitrile containing deuterated lumefantrine (LUM-d18) and desbutyl-lumefantrine (DBL-d9) as internal standards. Total chromatography time was 2.2min using an Hypersil Gold C18 column (20×2.1mm, 1.9µm), with a gradient using 0.5% formic acid in water (mobile phase A) and 0.5% formic acid in methanol (mobile phase B) at a flow rate of 0.5mL/min. The mass spectrometric quantification was performed in positive electro spray ionization (ESI+) mode using selected reaction monitoring (SRM). Measuring range was 21-529ng/mL for LUM and 1.9-47ng/mL for DBL in plasma. Inter- and intra-assay precision was within 10% coefficient of variation (CV) for all levels of both LUM and DBL. Accuracy was within ±10% for all levels of both LUM and DBL. This method requires 100µL plasma volume and its short retention times allow a high throughput. Samples were stable for a week at +5°C, and up to six months -20°C. The method was successfully applied for plasma LUM and DBL determination in children under 5 years of age with uncomplicated malaria, up to 28 days after a standard 3-day treatment with artemether-lumefantrine.

A field-adapted sampling and HPLC quantification method for lumefantrine and its desbutyl metabolite in whole blood spotted on filter paper.

A quantitative reverse-phase HPLC method with UV detection, for lumefantrine (LF) and desbutyllumefantrine (DLF) in whole blood spotted on filter paper was developed. The analytes were stabilized on filter paper by treatment of blood with phosphoric acid (1.6 mol/L). Halofantrine was used as internal standard and the analytes were extracted from filter paper using methanol. The methanolic extract was extracted with di-isopropylether after addition of acidic phosphate buffer (pH 2). Chromatographic separation was carried out on a Zorbax Eclipse XDB-phenyl column (4.6 mm x 150 mm, particle size 5 microm) at a flow rate of 1 mL/min using a mobile phase of acetonitrile-ammonium acetate buffer (0.1M ammonium acetate and 0.01 M acetic acid, pH 6.5) (10:90). The absorbance of the compounds was monitored at 335 nm. The average extraction recovery from filter paper ranged between 45-51% for LF and 25-33% for DLF for a concentration range between 300 and 3000 nM. Inter- and intra-assay coefficients of variation for LF and DLF were < or =9.2. Limits of quantification for LF and DLF were 300 nM. The method has been applied in malaria patients. In conclusion, a simple procedure for blood sampling and quantitative measurement of lumefantrine and desbutyllumefantrine suitable for field studies in resource-limited laboratories was developed.

A field-adapted HPLC method for determination of amodiaquine and its metabolite in whole blood dried on filter paper.

A reversed-phase high performance liquid chromatographic method was developed and validated for the quantitative determination of amodiaquine (AQ) and its metabolite desethylamodiaquine (DAQ) in whole blood collected on filter paper. The structure analogue 4-(4-dimethylamino-1-methylbutylamino)-7-chloroquinoline was used as internal standard. Upon collection, blood was added to 10% phosphoric acid in a 1:1 ratio and then spotted onto filter paper. The samples were alkalinized (pH approximately 9.2) with potassium hydroxide at the time of assay and the compounds were extracted together with internal standard into di-isopropyl ether and then re-extracted into an aqueous phase with 0.1M phosphate buffer at pH 4. The chromatographic analysis was performed using an Agilent Technologies ChemStation LC System. The absorbance of the compounds was monitored at 333 nm. Mean extraction recoveries of AQ and DAQ were 49 and 48%, respectively. Intra-day and inter-day coefficients of variation were <10.5%. The limit of quantification was 50 nM for both compounds (sample size 100 microl). Both AQ and DAQ that were previously reported to be unstable have been stored on filter paper for at least 19 weeks. The method was applied on samples from healthy volunteers.

Pharmacokinetic interactions between chloroquine, sulfadoxine and pyrimethamine and their bioequivalence in a generic fixed-dose combination in healthy volunteers in Uganda.

BACKGROUND: A pre-packaged fixed-dose formulation of chloroquine (CQ) and sulfadoxine/pyrimethamine (S/P) combination (Homapak) is widely used for the treatment of falciparum malaria in Ugandan children. It is however a product whose pharmacokinetics and interactions have not been studied. OBJECTIVES: To explore possible pharmacokinetic interactions between CQ and S/P during co-administration, and to determine their bioavailability in the locally made Homapak compared to the Good Manufacturing Practice (GMP) made formulations. METHODS: Thirty-two adult healthy volunteers were randomized into four groups and given single oral doses of fixed-dose CQ+S/P combination (Homapak), or GMP formulations of S/P (Fansidar), CQ (Pharco), or their combination. Plasma samples were followed for 21 days, analysed by HPLC-UV methods, with pharmacokinetic modeling using the WinNonlin software. RESULTS: Sulfadoxine in Homapak was more rapidly absorbed (ka = 0.55 h(-1)) than in Fansidar + CQ (ka = 0.27 h(-1), p=0.004), but not more than S in Fansidar alone group (ka = 0.32 h(-1), p=0.03). No significant differences were observed in the other pharmacokinetic parameters of S, P and CQ when given together or separately. The relative bioavailability of CQ and S in Homapak showed bioequivalence to reference formulations. CONCLUSIONS: There were no pharmacokinetic interactions between CQ, S and P when the compounds were given together, however, more investigations would be needed to explore this further. Compared with GMP made drugs, both S and CQ are bioequivalent in Homapak, the Ugandan made fixed-dose formulation. Furthermore, the absorption of S was more rapid which could be advantageous in malaria treatment.