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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Développement d'électrodes sélectives pour l'analyse de composés d'intérêt pharmaceutique : Antipaludéens et halogénures

Kimbeni Malongo, Trésor 25 June 2008 (has links)
RESUME Le travail de thèse porte sur le développement d’électrodes sélectives originales et performantes pour l’analyse de composés d’intérêt pharmaceutique. La partie introductive traite des notions relatives à l’électrochimie mais également de notions sur les molécules médicamenteuses étudiées, en l’occurrence les principes antipaludéens et l’iode. La partie expérimentale se subdivise en deux parties distinctes selon le type d’électrodes sélectives auxquelles font appel les techniques électrochimiques. La première partie concerne l’élaboration, la caractérisation et l’application des électrodes potentiométriques à membrane polymérique incluant une paire d’ions et sélectives à diverses molécules organiques pharmacologiquement actives (antipaludéens). Leur application aussi bien en analyse pharmaceutique qu’en cinétique de dissolution est décrite. La deuxième partie est consacrée à l’élaboration d’un type de senseur ampérométrique original à pâte de carbone à base d’argent micronisé ou colloïdal et à la comparaison de ses performances avec l’électrode d’argent métallique. L’intérêt analytique est mis en évidence par la détermination quantitative des iodures. Les différents aspects susceptibles d’influencer leur comportement, dont la nature des agents précipitants (tétraphénylborate de sodium et le tétrakis (4-chlorophényl) borate de potassium) et de plastifiants ont été investigués. Les bonnes performances des ces électrodes en analyse quantitative ont permis d’explorer les possibilités de leur utilisation à l’étude de la cinétique de dissolution. L’ampérométrie à électrode à pâte de carbone modifiée à base d’argent à l’échelle micronisée (35% m/m) couplée à la chromatographie liquide ionique s’est avérée très sensible vis-à-vis des iodures en particulier et des halogénures en général. Les facteurs susceptibles d’influencer les grandeurs de séparation et la réponse de l’électrode ont été investigués et l’exploitation du signal ampérométrique permet le dosage sélectif et rapide de faibles concentrations en iodures. Les informations fournies par les mesures réalisées en voltampérométrie cyclique à l’aide des mêmes électrodes permettent une bonne compréhension mécanistique quant au mode de détection ampérométrique évitant ainsi toute confusion à ce sujet et permettant l’optimisation du processus de détection. ------------------------------------------------ ABSTRACT This thesis describes the development of original and high performance selective electrodes for the analysis of several pharmaceutical compounds. The introduction describes the pharmaceutical compounds of interest (antimalarial drugs and iodine) and provides an overall understanding of the electrochemical groundwork pertaining to their analysis. The experimental aspect of the thesis is divided into two parts, each according to the type of electrode and electrochemical technique used for the analysis. The first part describes the design, characterization, and application of polymer membrane based ion selective potentiometric electrodes. Selectivity was provided by including ion pairs of several antimalarial drugs into the membrane. The feasibility of use of these electrodes in pharmaceutical analysis as well as in dissolution trials is also described in this part. The second part describes the design of an original silver-modified carbon paste amperometric sensor and compares its performances to those of a plain metallic silver electrode. The electrode has been modified by silver microparticles or by silver nanoparticles. Quantitative iodine determination serves to prove the usefulness of this new sensor in analytical chemistry. Different aspects, such as the nature of the counter ions (sodium tetraphenylborate and potassium tetrakis (4-chlorophenyl) borate) and the plastifying agents that are likely to influence electrode behaviour have been investigated. Since the electrodes have been shown to perform well in quantitative analysis, the possibility of use in dissolution trials was explored. Micronized silver-modified carbon paste electrode (35% Ag m/m) coupled to anionic-exchange liquid chromatography with amperometric detection was shown to be very sensitive with regards to the assay of halogenides in general and iodide in particular. After having investigated the various factors likely to influence chromatographic separation and electrode response, it was shown that the sensor could be used to rapidly and selectively determine low iodide concentrations in complex samples. Cyclic voltammetric analysis provided information concerning the mechanisms allowing amperometric detection, thus allowing an optimisation of the detection procedures.
12

Drug Analysis : Bioanalytical Method Development and Validation

Malm, Mikaela January 2008 (has links)
This thesis describes bioanalytical methods for drug determination in biological matrixes, with drugs in focus used against diseases largely affecting low-income countries. Solid-phase extraction is used for sample cleanup, and processed samples are analyzed by liquid chromatography. Developed bioanalytical methods are validated according to international guidelines. Eflornithine (DFMO) is a chiral drug, used for treating human African trypanosomiasis. A bioanalytical method for determination of DFMO enantiomers in plasma is presented. The enantiomers are detected by evaporative light-scattering detection. The method has been applied to determination of D-DFMO and L-DFMO in rats, after intravenous and oral administration of racemic DFMO. It is concluded that DFMO exhibits enantioselective absorption, with the more potent enantiomer L-DFMO being less favored. Sulfadoxine (SD) and sulfamethoxazole (SM) are sulfa-drugs used for malaria and pneumonia respectively. Two methods are described for simultaneous determination of SD and SM in capillary blood sampled on filter paper. The former method allows direct injection of extracts from dried blood spots (DBS), while for the latter method solid-phase extraction is added. Pre-analytical factors contributing to measurement uncertainty is also discussed, and it is concluded that it is of high importance that homogeneity in type of sampling paper and sampling volume is assured. Piperaquine (PQ) is an antimalarial, increasingly used in artemisinin combination therapy. A method for determination of piperaquine in DBS is presented. By using a monolithic LC column, a very short LC analysis of two minutes per sample is achieved. A method for simultaneous determination of three antiretroviral drugs i.e. lamivudine (3TC), zidovudine (AZT) and nevirapine (NVP), in DBS samples is described. The method is applied to drug determination in two subjects after receiving standard antiretroviral treatment. Conclusion is that the method is suitable for determination of 3TC and NVP, and to some extent for AZT.
13

Développement d'électrodes sélectives pour l'analyse de composés d'intérêt pharmaceutique: antipaludéens et halogénures

Kimbeni Malongo, Trésor 25 June 2008 (has links)
RESUME<p><p>Le travail de thèse porte sur le développement d’électrodes sélectives originales et performantes pour l’analyse de composés d’intérêt pharmaceutique. <p><p> La partie introductive traite des notions relatives à l’électrochimie mais également de notions sur les molécules médicamenteuses étudiées, en l’occurrence les principes antipaludéens et l’iode.<p><p> La partie expérimentale se subdivise en deux parties distinctes selon le type d’électrodes sélectives auxquelles font appel les techniques électrochimiques.<p><p> La première partie concerne l’élaboration, la caractérisation et l’application des électrodes potentiométriques à membrane polymérique incluant une paire d’ions et sélectives à diverses molécules organiques pharmacologiquement actives (antipaludéens). Leur application aussi bien en analyse pharmaceutique qu’en cinétique de dissolution est décrite.<p><p> La deuxième partie est consacrée à l’élaboration d’un type de senseur ampérométrique original à pâte de carbone à base d’argent micronisé ou colloïdal et à la comparaison de ses performances avec l’électrode d’argent métallique. L’intérêt analytique est mis en évidence par la détermination quantitative des iodures.<p><p> Les différents aspects susceptibles d’influencer leur comportement, dont la nature des agents précipitants (tétraphénylborate de sodium et le tétrakis (4-chlorophényl) borate de potassium) et de plastifiants ont été investigués.<p>Les bonnes performances des ces électrodes en analyse quantitative ont permis d’explorer les possibilités de leur utilisation à l’étude de la cinétique de dissolution.<p><p> L’ampérométrie à électrode à pâte de carbone modifiée à base d’argent à l’échelle micronisée (35% m/m) couplée à la chromatographie liquide ionique s’est avérée très sensible vis-à-vis des iodures en particulier et des halogénures en général. Les facteurs susceptibles d’influencer les grandeurs de séparation et la réponse de l’électrode ont été investigués et l’exploitation du signal ampérométrique permet le dosage sélectif et rapide de faibles concentrations en iodures. Les informations fournies par les mesures réalisées en voltampérométrie cyclique à l’aide des mêmes électrodes permettent une bonne compréhension mécanistique quant au mode de détection ampérométrique évitant ainsi toute confusion à ce sujet et permettant l’optimisation du processus de détection.<p>------------------------------------------------<p>ABSTRACT<p><p>This thesis describes the development of original and high performance selective electrodes for the analysis of several pharmaceutical compounds. <p><p>The introduction describes the pharmaceutical compounds of interest (antimalarial drugs and iodine) and provides an overall understanding of the electrochemical groundwork pertaining to their analysis.<p><p>The experimental aspect of the thesis is divided into two parts, each according to the type of electrode and electrochemical technique used for the analysis.<p>The first part describes the design, characterization, and application of polymer membrane based ion selective potentiometric electrodes. Selectivity was provided by including ion pairs of several antimalarial drugs into the membrane. The feasibility of use of these electrodes in pharmaceutical analysis as well as in dissolution trials is also described in this part.<p><p>The second part describes the design of an original silver-modified carbon paste amperometric sensor and compares its performances to those of a plain metallic silver electrode. The electrode has been modified by silver microparticles or by silver nanoparticles. Quantitative iodine determination serves to prove the usefulness of this new sensor in analytical chemistry.<p><p>Different aspects, such as the nature of the counter ions (sodium tetraphenylborate and potassium tetrakis (4-chlorophenyl) borate) and the plastifying agents that are likely to influence electrode behaviour have been investigated. <p><p>Since the electrodes have been shown to perform well in quantitative analysis, the possibility of use in dissolution trials was explored.<p><p>Micronized silver-modified carbon paste electrode (35% Ag m/m) coupled to anionic-exchange liquid chromatography with amperometric detection was shown to be very sensitive with regards to the assay of halogenides in general and iodide in particular. After having investigated the various factors likely to influence chromatographic separation and electrode response, it was shown that the sensor could be used to rapidly and selectively determine low iodide concentrations in complex samples. Cyclic voltammetric analysis provided information concerning the mechanisms allowing amperometric detection, thus allowing an optimisation of the detection procedures.<p> / Doctorat en Sciences biomédicales et pharmaceutiques / info:eu-repo/semantics/nonPublished
14

Knowledge and use of intermittent prevention for malaria among pregnant women attending antenatal clinics in health centers in the Federal Capital Territory, Nigeria

Emenike, Obiageli Ugwumsinachi 02 1900 (has links)
Background Plasmodium falciparum malaria during pregnancy poses a substantial risk to mother and foetus. In recent years, convincing evidence has shown that preventive methods such as the use of insecticide treated bed nets (ITNs) and intermittent preventive treatment (IPT) in pregnancy with sulphadoxine-pyrimethamine (IPTp-sp) can greatly reduce the adverse effects of malaria during pregnancy. Purpose The main purpose of the study was to assess the knowledge and use of Intermittent Preventive Treatment of Malaria among pregnant women receiving Antenatal Care at the primary health centers of the Federal Capital Territory, Abuja Nigeria. Methods A quantitative, descriptive, cross-sectional study was conducted Structured questionnaires were administered to 300 pregnant women aged between 18 and 49 years. Data was analysed using Statistical Package for Social Sciences (SPSS) 22. Results The results revealed that most of the respondents had knowledge about IPT, majority of the respondents had received IPT drugs, in the clinic, but unfortunately none of them were supervised by a health worker during taking of the drug. Few of the respondents did not take the drugs at all for fear of complication, some of them did not know exactly how many tablets were given to them and there was poor adherence to the Directly Observed Therapy (DOT) scheme. Conclusion Knowledge of malaria and IPT was good and many pregnant women received the drugs and used it, but some of them had challenges and did not use the drugs. / Health Studies / M.P.H.

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