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No. of bitstreams: 1 Reprodução Não Autorizada.pdf: 47716 bytes, checksum: 0353d988c60b584cfc9978721c498a11 (MD5) Previous issue date: 2015-12-21 / Tafenoquine (TQ) is an 8-aminoquinolone, synthetic analogue of primaquine which is in fase III tests for the treatment of human malaria. It shows better antimalarial activity than primaquine in vitro and is usually well tolerated in patients. There are some methods for TQ quantification in human plasm, but none uses Dispersive-Liquid-Liquid Microextraction (DLLME), an extraction technique that shows as mean advantages: miniaturization, low cost, high efficiency of extraction and pre-concentration and high potential for routine application. The aim of this study was to evaluate the use of DLLME to determine tafenoquine in human plasma. After protein precipitation, TQ was extracted from plasma by DLLME using chloroform and acetonitrile as extraction solvents and dispersants, respectively. The mobile phase consisted of methanol/acetonitrile/sodium acetate (10 mmol L-1, pH 6.7, 25oC)/acetic acid (50:30:20:0.1 v/v/v) and a C18 column (15 x 4.6mm, 5m) was used. The UV detection was performed at 262 nm and 1 mL/min as flow rate. The following factors that influences extraction efficiency were evaluated and optimized: dispersing solvent, solvent extractor, extractor solvent volume, pH and extraction time. During optimization, chloroform and acetonitrile showed higher recovery as an extractor and dispersant solvent, respectively. For evaluation of solvent extractor volume, the best result was obtained by adding 1 mL of a solution containing 30% of solvent extractor. For pH evaluation, greater extraction was observed by adding 100 L of 0.5 mol L- 1 NaOH solution in the sample. Finally, 2 min was the greater recovery extraction time. After optimized conditions, the method recovery was 78,3% and the lower limit of quantification was 50 ng mL-1. This method was considered linear over the range 50-1500 ng mL-1 (r2 = 0,99), with satisfactory accuracy and precision, and also may be useful in routine analyses specially because of the simplicity of this tecnique, rapidity and low use of solvents, presented features by DLLME tecnique / A Tafenoquina (TQ) corresponde a uma 8-aminoquinolina sintética e análoga da primaquina, que está em testes de fase III para o tratamento da malária humana. Apresenta melhor atividade antimalárica em relação ao congênere in vitro e é geralmente bem tolerada nos pacientes. Existem alguns métodos para quantificar a TQ em plasma humano, porém nenhum utiliza a técnica de microextração líquido-líquido dispersiva (DLLME, do inglês Dispersive Liquid- Liquid Microextraction), método que apresenta as seguintes vantagens: miniaturização, baixo custo, alta eficiência de extração e pré-concentração e elevado potencial para aplicação de rotina. O objetivo deste estudo foi avaliar o emprego da microextração líquido-líquido dispersiva para a determinação da tafenoquina em plasma humano. Após a precipitação de proteínas, TQ foi extraída do plasma por DLLME utilizando clorofórmio e acetonitrila como solvente extrator e dispersor, respectivamente. A fase móvel consistiu em metanol/acetonitrila/acetato de sódio (10 mmol L-1, pH 6,7, 25°C)/ácido acético (50:30:20:0,1 v/v/v) em conjunto com uma coluna C18 (15 x 4,6 mm, 5m). O comprimento de onda utilizado foi 262 nm com vazão de 1mL/min. Os seguintes fatores que influenciam a eficiência de extração foram avaliados e otimizados: solvente dispersor, solvente extrator, volume de solvente extrator, pH e tempo de extração. Durante a otimização, clorofórmio e acetonitrila apresentaram maior recuperação como solvente extrator e dispersor, respectivamente. Para volume de solvente extrator, obteve-se melhor resultado adicionando-se 1 mL de uma solução contendo 30% de solvente extrator. Na avaliação do pH, maior extração foi observada adicionando-se 100 L de solução de NaOH 0,5 mol L-1 na amostra. Por fim, o tempo de extração de 2 min foi o que apresentou maior recuperação. Com o método otimizado, a recuperação observada foi 78,3% e o limite inferior de quantificação foi 50 ng mL-1. O método foi linear no intervalo de 50 a 1500 ng mL-1 (r2 = 0,99) com precisão e exatidão satisfatórias e, portanto, pode ser útil em análises de rotina, especialmente pela simplicidade da técnica, rapidez e baixo uso de solvente, características apresentadas pela técnica de DLLME

This thesis describes bioanalytical methods for measuring melatonin and some anti-infective drugs in biological fluids. Solid-phase extraction (SPE) or protein precipitation was used for enrichment and purification of the analytes and Liquid Chromatography (LC) was used to analyze the samples. Developed methods were validated according to international guidelines. Melatonin is a hormone secreted by the pineal gland with a robust circadian rhythm. Bioanalytical methods for determination of melatonin in plasma and saliva have been developed which were used for monitoring melatonin levels in volunteers and patients suffering from sleep related diseases. Eflornithine (DFMO) is a chiral drug used for the treatment of human African trypanosomiasis. A bioanalytical method for determination of the DFMO enantiomers in plasma, after precolumn derivatization with o-phtalaldehyde and N-acetyl-L-cystein has been developed. The method has been used to study the L- and D-DFMO pharmacokinetics, in order to investigate the possible development of an oral treatment of DFMO. A method for simultaneous determination of three antiretroviral drugs i.e. Lamivudine (3TC), Zidovudine (AZT) and Nevirapine (NVP) in dried blood spots (DBS) was developed. The method was used for drug determination in two subjects after receiving standard antiretroviral treatment. The method seemed well suitable for the determination of 3TC and NVP and in some extent for AZT. Lumefantrine (LF) is one of the active components in a new fixed drug combination recommended by the WHO as a replacement to older drugs that has lost their effect. A method for the determination of LF in DBS was developed. The method is suitable for monitoring of drug treatment in rural settings. Tafenoquine is a new promising antimalarial drug under development. A method for the determination of Tafenoquine in plasma and in DBS is described. The method may be useful in future clinical studies in laboratory environment as well as in rural settings. / Felaktigt tryckt som Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology 703