A hidroxicloroquina (HCQ) é um importante fármaco quiral usado, principalmente, no tratamento de artrite reumatóide, lupus eritematoso sistêmico e malária e cujas propriedades farmacocinéticas e farmacodinâmicas são estereosseletivas. Em relação às propriedades farmacocinéticas, alguns estudos prévios indicam que o metabolismo estereosseletivo parece ser função da espécie estudada, o que implica na necessidade de métodos seletivos para a determinação de seus enantiômeros em materiais biológicos. Assim, propôs-se o desenvolvimento e a validação de métodos para análise dos enantiômeros do fármaco inalterado e de seus principais metabólitos em frações microssomais de homogeneizados de fígado de ratos e camundongos. Para tanto foram empregadas as técnicas de eletroforese capilar (CE) e de cromatografia líquida de alta eficiência (HPLC). Inicialmente foi desenvolvido um método por HPLC, em uma etapa, para a quantificação dos enantiômeros de dois metabólitos da HCQ, desetilcloroquina (DCQ) e desetilhidroxicloroquina (DHCQ) em microssomas de fígado de ratos e camundongos. A separação foi efetuada utilizando-se a coluna Chiralpak AD-RH e hexano:isopropanol (92:8, v/v) acrescido de 0,1% de dietilamina como fase móvel. O procedimento de extração líquido-líquido foi utilizado para a preparação das amostras. A metodologia desenvolvida resultou na completa resolução dos enantiômeros da HCQ, DCQ e DHCQ e pode ser considerada adequada, visto que os parâmetros de validação mostraram valores dentro dos limites exigidos na literatura. O segundo método desenvolvido permitiu a quantificação dos enantiômeros dos três metabólitos da HCQ: DCQ, DHCQ e bisdesetilcloroquina (BDCQ) em microssomas de fígado de camundongos. A separação foi efetuada utilizando-se um tubo capilar de sílica fundida e solução do eletrólito tris(hidroximetil)aminometano 100 mmol/L, ajustada a pH 9,0 com ácido fosfórico e acrescida de 1% (m/v) de β –CD - sulfatada e 30 mmol/L de β –CD - hidroxipropilada. O procedimento de extração líquido-líquido foi eficiente para remover interferentes e os parâmetros de validação mostraram valores dentro dos limites exigidos na literatura. Os métodos desenvolvidos foram aplicados no estudo in vitro do metabolismo da HCQ em frações microssomais de fígado dos animais, verificando-se que o principal metabólito formado é o (-)-(R)-DHCQ, para ambas espécies estudadas. / Hydroxychloroquine (HCQ) is an important chiral drug used specially in the treatment of rheumatoid arthritis, systemic lupus erythematosus and malaria, with stereoselective pharmacokinetic and pharmacodinamic properties. Concerning these properties, some previous studies indicate that the stereoselective metabolism seems to be a function of the studied species, therefore selective methods are required for the determination of its enantiomers in biological matrix. Thus, the present work reports the development and validation of methods for the analysis of the enantiomers of HCQ and its main metabolites in microsomal fraction of rats and mice liver homogenates. Capillary electrophoresis (CE) and high-performance liquid chromatography (HPLC) were used for this purpose. Initially, a one-step HPLC method was developed for the quantification of the enantiomers of two HCQ metabolites, desethylchloroquine (DCQ) and desethylhydroxychloroquine (DHCQ) in microsomal fraction of rats and mice liver homogenates. The separation was performed on a Chiralpak AD-RH column using hexane:isopropanol (92:8, v/v) plus 0.1% diethylamine as the mobile phase. Liquid-liquid extraction procedure was used for sample preparation. The developed methodology resulted in the complete resolution of HCQ, DCQ and DHCQ enantiomers and can be considered suitable because the validation parameters are in accordance with the limits established in the literature. The second developed method allowed the quantification of the enantiomers of the three HCQ metabolites, DCQ, DHCQ and bisdesethylchloroquine (BDCQ) in microsomal fraction of mice liver homogenates. The separation was performed using a fused-silica capillary tube and tris (hydroxymethyl) aminometane 100 mmol/L electrolyte solution, adjusted at pH 9.0 with phosphoric acid, containing 1% (w/v) sulfated- β -CD and 30 mmol/L hydroxypropyl- β -CD. The liquid-liquid extraction procedure was efficient to remove interferents and the validation parameters showed values within accordance to the literature. The developed methods were applied in the in vitro metabolism study of HCQ in microsomal fractions of the liver of the animals and it was verified that the main metabolite formed is (-)-(R)-DHCQ for both animal species studied.

As teorias neurobiológicas defendem que a esquizofrenia é essencialmente causada por alterações bioquímicas e estruturais do cérebro. A importância que os aminoácidos tem com a fisiopatologia da esquizofrenia e, por este envolvimento encontrar-se pouco esclarecido é que esta pesquisa teve como propósito desenvolver e validar uma metodologia analítica para a análise simultânea dos aminoácidos: glutamato, aspartato, serina, glicina, arginina e lisina em plasma de pacientes com diagnóstico de esquizofrenia, utilizando para isto a cromatografia líquida de alta eficiência com detecção por fluorescência. Os analitos foram inicialmente extraídos através do processo de precipitação protéica, com o solvente orgânico acetonitrila. Para que pudessem ser detectados por fluorescência os aminoácidos foram derivatizados empregando orto-ftalaldeído na presença de B-mercaptoetanol. O tempo total de separação foi de 18 minutos em coluna analítica LiChroCART® RP-18 (Merck, 125mm, 4mm d.i., 5m) no modo de eluição gradiente com tampão acetato de sódio 0,1 mol/L (pH 7,0, A) e acetonitrila e água (B), na proporção 70:30, respectivamente, para posterior detecção por fluorescência (excitação 340 nm, emissão 450 nm). O método foi validado segundo os critérios estabelecidos pela Agência Nacional de Vigilância Sanitária (ANVISA). A resposta do detector encontrou-se linear na faixa de 9,6 a 192 pmol/mL para todos os aminoácidos. O limite de detecção estabelecido foi de 7,68 pmol/mL e o limite de quantificação foi de 9,6 pmol/mL. A recuperação foi superior a 70%. A precisão e exatidão intra-ensaio variou de 3,6% a 5,3% e 3,1% a 8,3%, respectivamente. A precisão e exatidão interensaio variou de 3,6% a 7,1% e 3,1% a 11,4%, respectivamente. A especificidade foi determinada para os seguintes interferentes: lorazepam, diazepam, clonazepam, alprazolam, haloperidol, levomepromazina, propranolol, ranitidina, fluoxetina, olanzapina, carbamazepina, diclofenaco, amiodarona, sulfametoxazol e, ainda, plasma hemolisado, normal e lipêmico. O método desenvolvido e validado mostrou ser eficiente na determinação simultânea de aminoácidos podendo ser aplicado em amostras de pacientes esquizofrênicos a fim de investigar seu envolvimento com esta desordem psiquiátrica tão intrigante. / Schizophrenia is primarily caused by structural and biochemical changes in the brain according to the main neurobiological theory, including the amino acids concentrations in the human plasma. The relation between these amino acids concentrations and the schizophrenia needs more clarification. Therefore, an analytical tool is necessary to provide which of these amino acids are related with this mental disease. The aim of this research was to develop and to validate an analytical methodology using High Performance Liquid Chromatography with fluorescence detection for simultaneous analysis of the main human amino acids, which are: glutamate, aspartate, serine, glycine, arginine and lysine in plasma of schizophrenic patients. Protein precipitation was the extraction technique chosen for the amino acids determination using acetonitrile as organic solvent. The derivatization was conducted by the reaction between the amino acids and ortho-phthalaldehyde in the presence of B-mercaptoethanol. The separation was achieved using the analytical column LiChroCART® RP-18 (Merck, 125mm, 4mm ID, 5mm) by gradient elution in 18 minutes. The mobile phase was composed by sodium acetate buffer 0.1 mol / L (pH 7.0; A) and acetonitrile: water (B) (70:30, v/v). The detection was performed by fluorescence (excitation 340 nm, emission 450 nm). The method was validated according to criteria established by the regulatory agency (ANVISA). The detector response was found linear in the range 9.6 to 192 pmol / mL for all amino acids. The detection limit was set at 7.68 pmol / mL and the limit of quantification was 9.6 pmol / mL. The recovery was above 70%. The precision and accuracy intra-assay ranged from 3.6% to 5.3% and 3.1% to 8.3%, respectively. The precision and accuracy inter-assay ranged from 3.6% to 7.1% and 3.1% to 11.4%, respectively. The specificity was determined for the following possible interferents: lorazepam, diazepam, clonazepam, alprazolam, haloperidol, levomepromazine, propranolol, ranitidine, fluoxetine, olanzapine, carbamazepine, diclofenac, amiodarone, trimethoprim. Plasma hemolyzed, lipemic and normal were evaluated. This method was adequate to simultaneous determination of amino acids, therefore it can be applied to samples of schizophrenic patients and consequently, providing information of the main amino acids involvement with this psychiatric disorder.

The bacterium Rhodococcus is a potential source for novel antimicrobial metabolites. Recently, the Rhodococcus strain MTM3W5.2 was isolated from a soil sample collected from Morristown, East Tennessee and was found to produce an inhibitor molecule that is active against similar Rhodococcus species. The aim of this research is to extract, purify, and characterize the active compound. The compound was obtained from both agar and broth cultures of strain MTM3W5.2 and purified by primary fractionation of crude extract on a Sephadex LH-20 column, followed by semi-preparative reversed phase column chromatography. Final purification was achieved using multiple rounds of an analytical C18 HPLC column. Based on the results obtained from UV-Vis, FT-IR, and HR-MS, the molecule is a polyketide with a molecular formula of C52H78O13 and an exact mass of 911.5490 amu. The partial structure of this compound has been determined using 1D and 2D NMR spectroscopy.

Due to the large gaps in the fossil record, the evolutionary history of the mammalian order Cetacea is incomplete and controversial. Increasingly researchers are utilizing molecular and biochemical procedures to supplement cetacean paleontology. One of these methods is the comparison of amino acid sequences of myoglobin among species of this order. since this method is time-consuming and expensive, an alternative procedure is desirable.

No description available.

In modern chemical laboratories, high performance liquid chromatography (HPLC) has become the technique of choice amongst separation scientists as evidenced by the huge body of published literature that employ the technique as the pre-eminent analytical method. Increasingly analytical chemists are seeking to determine the chemical signature (or fingerprint) of complex and perhaps even simple samples. The analysis of environmental samples, natural products, such as essential oils, the evaluation of illicit drugs, or the quality assurance of pharmaceuticals are just four areas where chemical fingerprinting may be important. The chemical classification of these types of mixtures can be undertaken using chromatographic methods of analysis coupled with detection processes that provide identification ie. mass spectroscopy (MS), infrared spectroscopy (IR), atomic spectroscopy (ICP) and nuclear magnetic resonance spectroscopy (NMR). While these techniques find widespread use and their applications are growing at a rapid rate, their limitations as routine applications for determining chemical signatures, is limited by the initial purchase price and the high associated running costs; especially for hyphenated liquid chromatographic systems. In general, a high degree of operator expertise is also required to ensure correct operation and interpretation of the results. While complete chemical specification may be undertaken by using multiple hyphenated methods, none of the above mentioned techniques provide for a rapid means of detection on a routine or continuous mode of operation. This can limit their application. However, an alternative to monitor and evaluate the chemical signature of complex samples is to employ multidimensional separations. In the expanded multidimensional separation space the probability that two species will elute with exactly the same retention time in both separation dimensions decreases compared to the one-dimensional separation. This probability further decreases as the separation mechanisms become more divergent and the two-dimensional separation space is maximised. Hence, the uniqueness of a two-dimensional retention time increases and thereby the multidimensional separation approach becomes a means of chemical fingerprinting. Hence 2D-HPLC technique is a powerful and less expensive method of separation compared to hyphenated techniques. This thesis describes the development of a stand-alone 2D-HPLC system for the separation of complex samples. A comprehensive 2D-HPLC software package has been developed for data acquisition, hardware control, data processing and graphical presentation. Two data acquisition hardware modules have also been developed. These hardware and software modules have been integrated with existing equipment in our laboratory. The performance of this newly developed 2D-HPLC system has been successfully evaluated. All these details have been described in the five chapters of this thesis. / Master of Science (Honours)

A novel analytical method is developed to examine the chemical composition of plant oils by electrospray ionisation high-resolution Fourier transform ion cyclotron resonance mass spectrometry in both positive- and negative-ion modes. To date, this is the first reported application of this technique for the study of macadamia nut oil. Samples of macadamia nut oil from the Macadamia Integrifolia- Proteaceae family (smooth shell) are examined. The fatty acid profile of the oil is obtained by this mass spectrometric examination of the transesterified and hydrolysed oil samples. The Fourier transform ion-cyclotron resonance mass spectrometry results are compared to those obtained from similar samples using gas chromatography-mass spectrometry techniques. High performance liquid chromatography and Fourier transform ion cyclotron resonance mass spectrometry are used to separate and assign the isomers present in the methanol extract of the oils in separate experiments. Significant results in this study include: - The first observation and identity of a number of oxidised triacylglycerols in macadamia oil samples. - The first observation of oxidised and free fatty acids, measured directly in hydrolysed oil and in the methanol extract of macadamia oil. - High resolution Fourier transform ion cyclotron resonance mass spectrometry in broadband mode which enables isobars to be observed. - Esterified oil Fourier transform ion cyclotron resonance mass spectrometry results are consistent with our gas chromatography-mass spectrometry results and with the results of similar studies on macadamia oil in the literature. - A number of fatty acids with odd number of carbon atoms are observed in the oil. - In electrospray ionisation Fourier transform ion cyclotron resonance mass spectrometry of oils, the sample preparation is straightforward. The sample is dissolved in methanol or acetonitrile and the solution is introduced to the electrospray source directly. Introducing oil samples to the gas chromatograph-mass spectrometer needs the oils to be esterified prior to the analysis. - In this work, state-of-the-art mass spectrometry demonstrates distinct advantages in comparison to gas chromatography measurements such as direct identification of free fatty acids in oil samples, whereas this is not possible in gas chromatography-mass spectrometry due to the required esterification step prior to the analysis. - High performance liquid chromatography fraction collection is combined with Fourier transform ion cyclotron resonance mass spectrometry in off-line mode and found to improve the sensitivity, selectivity and signal to noise levels due to the lower number of compounds in each high performance liquid chromatography fraction compared to the methanol extract of macadamia oil sample. Also isomers of monoacylglycerols have been resolved using the high performance liquid chromatography technique.

Thesis (Ph. D.)--Ohio State University, 2007. / Title from first page of PDF file. Includes bibliographical references (p. 149-167).

Thesis (Ph. D.)--University of Hong Kong, 2006. / Title proper from title frame. Also available in printed format.

Dissolved organic matter (DOM) is comprised of a complex array of molecular constituents that are linked to many globally-relevant processes and yet this material is still largely molecularly uncharacterized. Research presented here attempted to probe the molecular complexity of this material from both Arctic and temperate climates via multifaceted and novel approaches. DOM collected from remote Arctic watersheds provided evidence to suggest that permafrost-disturbed systems contain more photochemically- and biologically-labile material than undisturbed systems. These results have large implications for predicted increasing temperatures where widespread permafrost melt would significantly impact stores of organic carbon in polar environments. In attempting to address the complexities and reactivity of DOM within global environments, more information at the molecular-level is necessary. Further research sought to unravel the molecularly uncharacterized fraction via use of nuclear magnetic resonance (NMR) spectroscopy in conjunction with hyphenated and varied analytical techniques. Directly hyphenated high performance size exclusion chromatography (HPSEC) with NMR was explored. This hyphenation was found to separate DOM into structurally distinct fractions but proved limited at reducing DOM heterogeneity. Of the many high performance liquid chromatography (HPLC) techniques tested, hydrophilic interaction chromatography (HILIC) was found the most effective at simplifying DOM. HILIC separations utilizing a sample from Florida resulted in fractions with highly resolved NMR signals and substantial reduction in heterogeneity. Further development with a 2D-HILIC/HILIC system to achieve additional fractionation was employed. This method produced fractions of DOM that were homogenous enough to produce excellent resolution and spectral dispersion, permitting 2D and 3D NMR experiments to be performed. Extensive NMR analyses of these fractions demonstrated strong evidence for the presence of highly oxidized sterols. All fractions, however, provided 2D NMR spectra consistent with oxidized polycyclic structures and support emerging data and hypotheses suggesting that cyclic structures, likely derived from terpenoids, are an abundant, refractory and major component of DOM. Research presented within this thesis demonstrates that HILIC and NMR are excellent co-techniques for the analysis of DOM as well as that oxidized sterols and other cyclic components with significant hydroxyl and carboxyl substituents are major constituents in DOM.