Thesis (M.S.)--Michigan State University. Dept. of Chemistry, 2006. / Title from PDF t.p. (viewed on Nov. 20, 2008) Includes bibliographical references (p. 105-110). Also issued in print.

Thesis (Ph. D.)--West Virginia University, 2009. / Title from document title page. Document formatted into pages; contains xxiii, 276 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 261-276).

Thesis (Ph.D.)--Ohio University, November, 2007. / Release of full electronic text on OhioLINK has been delayed until November 30, 2008 Includes bibliographical references (leaves 147-164)

Thesis (Ph.D.)--Ohio University, November, 2007. / Title from PDF t.p. Release of full electronic text on OhioLINK has been delayed until November 30, 2008 Includes bibliographical references (leaves 147-164)

Thesis (Ph. D.)--West Virginia University, 2009. / Title from document title page. Document formatted into pages; contains xiv, 118 p. : ill. (some col.). Includes abstract. Includes bibliographical references.

A dispersive liquid-liquid microextraction (DLLME) method has been developed, optimized and validated for the extraction of seven beta-agonists (Cimaterol, Cimbuterol, Clenproperol, Clenbuterol, Ractopamine, Isoxsuprine and Ritodrine) from bovine muscle. The homogenized tissue samples were hydrolyzed enzymaticaly by beta-glucuronidase and extracted with DLLME. The extraction parameters (pH, extraction solvent, extraction solvent volume, disperser solvent) were accurately optimized. Separation of the beta-agonists was by gradient elution on C18 LC column using acetonitrile and formic acid aqueous solutions as mobile phases, multiple reaction monitoring (MRM) scan mode was used. The seven beta-agonists were then simultaneous determined and identified in single analysis using 4000 Qtrap LC-MS/MS system. The DLLME method was validated using ISO 17025 and the EU criteria (Commission Decision 2002/657/EC) for validation of analytical method, good precision, repeatability and spiked recoveries were obtained. The limits of detection and quantification for the residues were between 0.0728 – 0.0922 μg/kg and 0.243 – 0.307 μg/kg respectively for beta-agonists. The overall recoveries were between 85% and 100% with the relative standard deviation of (RSDs) between 3.0% and 10%. The recoveries from the developed DLLME method were compared with those obtained from dSPE. DLLME proved to be comparable to SPE. The real samples test showed that the DLLME method developed is accurate and sensitive for the determination of beta-agonist residues in bovine muscle. / Chemistry / M. Sc. (Analytical Chemistry)

Focus of this study was on the development of one of the faster, simpler, cost effective and environmentally friendly sample pre-treatment techniques which employs a supported liquid membrane, in this case a Hollow-fiber supported liquid membrane (HF-SLM) for determination of seven (7) quinolone antibiotics (enrofloxacin, ciprofloxacin, danofloxacin, difloxacin, norfloxacin, nalidixic acid and sarafloxacin) in bovine kidney samples followed by LC-MS/MS analysis. The key parameters of the method were optimized and the method was validated following the 2002/657 EC guidelines. The optimum HF-SLM conditions were therefore; NaH2PO4 as a donor phase at pH 7, 0.1% formic acid at pH 3 as acceptor phase. Triethylamine was the optimized liquid membrane and the stirring time was optimized at 1 hour. Separation of the 7 quinolones including 3 internal standards (enrofloxacin-d5, norfloxacin-d5 and difloxacin-d3) was carried out on a Phenomenex Kinetex 2.6 μm XB-C18, 100 mm x 4.6 mm, 100Å column. Validation parameters such as Correlation coefficients (r2) ranging from 0.9714-0.9975 were obtained, while limit of detection (LOD) ranged between 3-39 ug kg-1 and limit of quantification (LOQ) ranged between 10-130 ug kg-1. The obtained limits at which it can be concluded with an error probability of α = 95% that a sample is non-compliant (CCα) ranged from 28 – 422 ug kg-1 while CCβ; the smallest content of the substance that may be detected, identified or quantified in a sample with an error probability of β = 95%, ranged from 29 – 454 ug kg-1. The method was found to be reproducible with CVs ≤ 23 %. The tested samples from Botswana local abattoirs showed no presence of quinolone antibiotics when the method was applied to real bovine kidney samples. Hollow-fiber supported liquid membrane can therefore be used for extraction of biological samples since it is a “greener technique” which uses less solvent which are less harmful to the environment when disposed as compared to dispersive Solid Phase Extraction (dSPE). / Chemistry / M. Sc. (Chemistry)

Made available in DSpace on 2014-06-11T19:35:08Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-04-23Bitstream added on 2014-06-13T18:46:23Z : No. of bitstreams: 1 pivatto_m_dr_araiq.pdf: 3895401 bytes, checksum: 8f00934510e296fa101a80060a9db12a (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / O presente trabalho teve como objetivo o estudo das vias biossintéticas dos alcalóides piperidínicos presentes em Senna spectabilis, motivado pela potente atividade anticolinesterásica e baixa toxicidade observada no derivado (–)-3-O-acetil-espectalina (15), eleito como composto líder para o desenvolvimento de fármacos anti-Alzheimer que estão em fase de estudos pré-clínicos. Por outro lado, o interesse acadêmico no conhecimento das vias metabólicas, pode levar a estudos futuros de engenharia genética para potencializar a produção desses metabólitos uma vez que a síntese é extremamente complexa em função da presença de três centros estereogênicos. Tendo isso em vista, foram selecionadas seis espécies de Senna e Cassia para avaliar a presença dos alcalóides e selecionar aquela que os produz em maior quantidade. Foram estudadas as flores de S. spectabilis, S. multijuga, S. macranthera, S. velutina, C. fistula, C. leptophylla, sendo que só foram detectados alcalóides piperidínicos e piridínicos em S. spectabilis e S. multijuga, respectivamente, utilizando a espectrometria de massas tandem. Embora sejam de classes diferentes, esses metabólitos têm padrão de substituição similar, porém, apresentaram atividade anticolinesterásica diferenciada. De S. spectabilis foram isolados os alcalóides piperidínicos: (–)-cassina (1), (–)-espectalina (9), (–)-3-O-acetil-espectalina (15), (–)-3-O-acetil-cassina (16) e identificados 7-hidroxi-carnavalina (71), 7-hidroxi-cassina (18) e/ou espicigerina (42) utilizando a EM. De S. multijuga foram isolados os alcalóides piridínicos: 7'-multijuguinona (67) e 12'-hidroxi-7'-multijuguinona (69) e identificados 7'-multijuguinol (68) e 12'-hidroxi-7'- multijuguinol (70). Para os estudos biossintéticos dos alcalóides piperidínicos foi inicialmente proposta a biogênese onde lisina e acetato foram eleitos potenciais... / The following work encompass as main goal the study of biosynthetic pathways to produce piperidine alkaloids using Senna spectabilis as natural matrix. Such research was instigated due to the high acetylcholinesterase activity and low toxicity showed by the derivative (–)-3-O-acetyl-spectaline (15), selected as a lead compound against Alzheimer’s disease and currently under pre-clinical trials. Still yet, the academic interest on researching metabolic pathways that may lead to further genetic engineering studies to enhance the production of these metabolites is of extremely importance, due to the inability of producing any commercially viable synthetic strategy for their stereogenic centers. We selected six Senna and Cassia species to evaluate the presence of these metabolites aiming to select which matrix will produce them the most. We studied flowers from S. spectabilis, S. multijuga, S. macranthera, S. velutina, C. fistula and C. leptophylla. From those, we were able to detect piperidine and pyridine alkaloids only in S. spectabilis and S. multijuga, respectively, using tandem mass spectrometry. Regardless of the different structural nature towards 15, those metabolites have similar substitution patterns and showed differential acetylcholinesterase activity. From S. spectabilis were isolated the piperidine alkaloids: (–)-cassine (1), (–)-spectaline (9), (–)-3-O-acetyl-spectaline (15), (–)-3-O-acetyl-cassine (16), and identified 7-hidroxy- carnavaline (71), 7-hidroxy-cassine (18) and/or spicigerine (42) by tandem mass spectrometry and from S. multijuga were isolated the pyridine alkaloids: 7'-multijuguinone (67), 12'-hydroxy-7'-multijuguinone (69) and, identified by MS: 7'-multijuguinol (68) and 12'-hydroxy-7'-multijuguinol (70). We initially proposed the incorporation of lysine and acetate as main precursors of the piperidine alkaloids biosynthetic pathway and thus... (Complete abstract click electronic access below)

Resumo: O presente trabalho teve como objetivo o estudo das vias biossintéticas dos alcalóides piperidínicos presentes em Senna spectabilis, motivado pela potente atividade anticolinesterásica e baixa toxicidade observada no derivado (-)-3-O-acetil-espectalina (15), eleito como composto líder para o desenvolvimento de fármacos anti-Alzheimer que estão em fase de estudos pré-clínicos. Por outro lado, o interesse acadêmico no conhecimento das vias metabólicas, pode levar a estudos futuros de engenharia genética para potencializar a produção desses metabólitos uma vez que a síntese é extremamente complexa em função da presença de três centros estereogênicos. Tendo isso em vista, foram selecionadas seis espécies de Senna e Cassia para avaliar a presença dos alcalóides e selecionar aquela que os produz em maior quantidade. Foram estudadas as flores de S. spectabilis, S. multijuga, S. macranthera, S. velutina, C. fistula, C. leptophylla, sendo que só foram detectados alcalóides piperidínicos e piridínicos em S. spectabilis e S. multijuga, respectivamente, utilizando a espectrometria de massas tandem. Embora sejam de classes diferentes, esses metabólitos têm padrão de substituição similar, porém, apresentaram atividade anticolinesterásica diferenciada. De S. spectabilis foram isolados os alcalóides piperidínicos: (-)-cassina (1), (-)-espectalina (9), (-)-3-O-acetil-espectalina (15), (-)-3-O-acetil-cassina (16) e identificados 7-hidroxi-carnavalina (71), 7-hidroxi-cassina (18) e/ou espicigerina (42) utilizando a EM. De S. multijuga foram isolados os alcalóides piridínicos: 7'-multijuguinona (67) e 12'-hidroxi-7'-multijuguinona (69) e identificados 7'-multijuguinol (68) e 12'-hidroxi-7'- multijuguinol (70). Para os estudos biossintéticos dos alcalóides piperidínicos foi inicialmente proposta a biogênese onde lisina e acetato foram eleitos potenciais... (resumo completo, clicar acesso eletrônico abaixo) / Abstract: The following work encompass as main goal the study of biosynthetic pathways to produce piperidine alkaloids using Senna spectabilis as natural matrix. Such research was instigated due to the high acetylcholinesterase activity and low toxicity showed by the derivative (-)-3-O-acetyl-spectaline (15), selected as a lead compound against Alzheimer's disease and currently under pre-clinical trials. Still yet, the academic interest on researching metabolic pathways that may lead to further genetic engineering studies to enhance the production of these metabolites is of extremely importance, due to the inability of producing any commercially viable synthetic strategy for their stereogenic centers. We selected six Senna and Cassia species to evaluate the presence of these metabolites aiming to select which matrix will produce them the most. We studied flowers from S. spectabilis, S. multijuga, S. macranthera, S. velutina, C. fistula and C. leptophylla. From those, we were able to detect piperidine and pyridine alkaloids only in S. spectabilis and S. multijuga, respectively, using tandem mass spectrometry. Regardless of the different structural nature towards 15, those metabolites have similar substitution patterns and showed differential acetylcholinesterase activity. From S. spectabilis were isolated the piperidine alkaloids: (-)-cassine (1), (-)-spectaline (9), (-)-3-O-acetyl-spectaline (15), (-)-3-O-acetyl-cassine (16), and identified 7-hidroxy- carnavaline (71), 7-hidroxy-cassine (18) and/or spicigerine (42) by tandem mass spectrometry and from S. multijuga were isolated the pyridine alkaloids: 7'-multijuguinone (67), 12'-hydroxy-7'-multijuguinone (69) and, identified by MS: 7'-multijuguinol (68) and 12'-hydroxy-7'-multijuguinol (70). We initially proposed the incorporation of lysine and acetate as main precursors of the piperidine alkaloids biosynthetic pathway and thus... (Complete abstract click electronic access below) / Orientador: Vanderlan da Silva Bolzani / Coorientador: Maysa Furlan / Banca: Ian Castro-Gamboa / Banca: Frederico Guaré Cruz / Banca: Márcia Nasser Lopes / Banca: Maria Claudia Marx Young / Doutor

Orientador: Jose Luiz Donato / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Ciencias Medicas / Made available in DSpace on 2018-08-10T07:16:04Z (GMT). No. of bitstreams: 1 Pioto_LigiaRodrigues_D.pdf: 680751 bytes, checksum: 6d472989ce55c9ad510ce3f7fffb6630 (MD5) Previous issue date: 2007 / Resumo: Foi desenvolvido um métdo rápido, sensível e específico para determinação de metotrexato em plasma sanguíneo humano por cromatografia líquida acoplada a espectrometria de massas em série usando folinato de cálcio como padrão interno. O metotrexato foi extraído do plasma humano, utilizando-se precipitação de proteínas plasmáticas com acetonitrila como eluente.O método tem uma corrida cromatográfica de 3,5 minutos usando uma coluna analítica C18 (4,6 mm x 75 mm d.i, 3.5 µm tamanho das partículas) e a curva de calibração foi linear de 10 a 300 ng.mL-1.A recuperação do método de extração foi, em média, de 76,5% e o limite de quantificação para o metotrexato foi de 10 ng.mL-1 / Abstract: A rapid, sensitive and specific method was developed for the determination and quantitation of methotrexate, in human blood plasma by liquid chromatography coupled with tandem mass spectrometry using calcium folinate as internal standard. Methotrexate was extracted from 0,2 mL human plasma by protein precipitation procedure using acetonitrile as eluent. The method included a chromatographic run of 3,5 minutes using a C18 analytical column (4,6 mm x 75 mm i.d., 3.5 µm particle size) and the linear calibration curve over the range from 10 to 300 ng mL-1. Recoveries were greater than 76.5% and the limit of uantitation of methotrexate was 10 ng mL-1 / Doutorado / Mestre em Farmacologia