Добірка наукової літератури з теми "False chirality"

Abstract Proper assignment of left- and right-handed labels to general chiral objects is known to be a theoretically unfeasible problem. Attempts to utilize a pseudoscalar function to distinguish enantiomers face two unavoidable difficulties: false chiral zeros and unhanded chiral states. In here, we demonstrate how both of these problems can be solved in the context of light–matter interactions. First, we introduce a two-dimensional quantity called complex electromagnetic chirality that solves the problem of false chiral zeros. Next, we define an infinite-dimensional pseudovector called chirality signature that completely quantifies the multidimensional nature of electromagnetic chirality, does not have false global chiral zeros, and allows to continuously distinguish any pair of enantiomers because it does not produce unhanded chiral states. We prove that the introduced measures are invariant under the largest group of symmetries of Maxwell’s equations—the conformal group. The complete, continuous, and conformally invariant quantification of electromagnetic chirality provided by the chirality signature distinguishes it as a particularly suitable tool for the study of chirality and its applications.

The 1884 suggestion of Pierre Curie (1859–1906) that the type of dissymmetry shown by collinear electric and magnetic fields may induce an enantiomeric excess, in a chemical reaction that would otherwise produce a racemic mixture, is explored in the context of fundamental symmetry arguments. Curie’s arrangement exhibits false chirality (time-noninvariant enantiomorphism), and so it may not induce absolute enantioselection (ae) in a process that has reached thermodynamic equilibrium, since it does not lift the degeneracy of chiral enantiomers. However, it may do so in far-from-equilibrium processes via a breakdown in microscopic reversibility analogous to that observed in elementary particle processes under the influence of CP violation, the associated force possessing false chirality with respect to CP enantiomorphism. In contrast, an influence like circularly polarized light exhibiting true chirality (time-invariant enantiomorphism) lifts the degeneracy of enantiomers, and so may induce ae in all circumstances. Although to date, ae has not been observed under the influence of Curie’s arrangement of collinear electric and magnetic fields, it is argued that two different experiments have now demonstrated ae under a falsely chiral influence in systems far from equilibrium, namely in a spinning sample under a gravitational field, and in the separation of enantiomers at a ferromagnetic surface.

Peptides can recognize and selectively bind to a wide variety of materials dependent on both their surface properties and the environment. Biopanning with phage or cell peptide display libraries can identify material-specific binding peptides. However, the limitations with sequence diversity of traditional bacteriophage (phage) display libraries and loss of unique phage clones during the amplification cycles results in a smaller pool of peptide sequences identified. False positive sequences tend to emerge during the biopanning process due to highly proliferating, yet nonspecific, phages. In order to overcome this limitation of traditional biopanning methodology, a modified method using high-throughput next generation sequencing (HTS) was tested to select for unique peptides specific to two types of single wall carbon nanotube (SWNTs) sources with varying diameter distribution and chirality. Here, the process, analysis, and characterization of peptide sequences identified using the modified method is further described and compared to a peptide identified in literature using the traditional method. Selected sequences from this study were incorporated in a SWNT dispersion experiment to probe their selectivity to the nanotube diameter. We show that NHTS can uncover unique binding sequences that might have otherwise been lost during the traditional biopanning method.

We propose an extended Quantum Chromodynamics (XQCD) Lagrangian in which the fermions are coupled to elementary scalar fields through a Yukawa coupling which preserves chiral invariance. Our principle motivation is to find a new lattice formulation for QCD which avoids the source of critical slowing down usually encountered as the bare quark mass is tuned to the chiral limit. The phase diagram and the weak coupling limit for XQCD are studied. They suggest a conjecture that the continuum limit of XQCD is the same as the continuum limit of conventional lattice formulation of QCD. As examples of such universality, we present the large N solutions of two prototype models for XQCD, in which the mass of the spurious pion and sigma resonance go to infinity with the cut-off. Even if the universality conjecture turns out to be false, we believe that XQCD will still be useful as a low energy effective action for QCD phenomenology on the lattice. Numerical simulations are recommended to further investigate the possible benefits of XQCD in extracting QCD predictions.

L’énantioséparation de précision est essentielle pour les industries pharmaceutiques et alimentaires. Les techniques conventionnelles de séparation chirale offrent un large éventail de méthodes, qui reposent toutes sur des sélecteurs chiraux - des phases stationnaires ou des molécules qui distinguent les énantiomères par une interaction stéréospécifique. Malgré le grand nombre de sélecteurs naturels et synthétiques actuellement utilisés, la demande croissante d’énantiopurité stimule la recherche de nouvelles méthodes polyvalentes.Le but de cette thèse est d'étudier des méthodes alternatives de séparation chirale impliquant l'application de champs magnétiques dans diverses configurations. Une idée est centrée sur le concept de vraie et fausse chiralité, introduit par L. Barron pour les systèmes dynamiques d'objets individuels et de grandeurs physiques vectorielles. Sa discussion indique explicitement que ni les champs magnétiques ni électriques statiques, ni aucune combinaison de ceux-ci, ne possèdent une véritable chiralité, la caractéristique requise pour induire une discrimination énantiomérique. Cependant, sa théorie suggère l’existence d’un analogue moléculaire de l’effet Faraday bien connu sous forme de l’application colinéaire d’un champ magnétique à un flux moléculaire.Alternativement, une configuration perpendiculaire au flux moléculaire impliquant un substrat ferromagnétique a démontré des interactions de spin énantiospécifiques, également connues sous le nom d'effet CISS. À cet égard, notre objectif principal était d’explorer une telle interaction dans des conditions dynamiques d’électrophorèse capillaire, qui permet une détection simple et rapide, tout en introduisant des substrats de Ni le long du flux de molécules et en appliquant un champ magnétique orthogonal.Enfin, la configuration orthogonale du champ magnétique a été exploitée pour étudier le comportement dynamique d'objets électropolarisés. Il a été démontré que la rotation présenté par différents objets sous l'effet magnétohydrodynamique induit par la force de Lorentz dépendent de la polarité du champ magnétique. Leur comportement dynamique en fonction du temps ressemble à celui de systèmes faussement chiraux
High-purity enantioseparation is essential for the pharmaceutical and food industries. Conventional chiral separation techniques provide a wide range of methods, all of which rely on chiral selectors - stationary phases or molecules that discriminate enantiomers through stereospecific interaction. Despite the vast number of natural and synthetic selectors currently in use, the increasing demand for enantiopurity is driving research for new and versatile methods.The aim of this thesis is to investigate alternative methods of chiral separation that involve the application of magnetic fields in various configurations. One idea centers around the concept of true and false chirality, which was introduced by L. Barron for dynamic systems of individual objects and physical vector quantities. His discussion explicitly states that neither static magnetic nor electric fields, nor any combination of those, possess true chirality, the feature required to induce enantiomeric discimination. However, his theory suggests a molecular analog of the well-known Faraday effect based on the collinear application of magnetic field to a molecular flow.Alternatively, a perpendicular configuration with the molecular flow involving a ferromagnetic substrate has demonstrated enantiospecific spin interactions, otherwise known as the CISS effect. In this regard, our main objective was the further exploration of such interactions in dynamic conditions of capillary electrophoresis, which provides simple and fast detection, while introducing Ni substrates along the flow of molecules and applying an orthogonal magnetic field.Lastly, the orthogonal configuration of the magnetic field was exploited to study the dynamic behavior of electropolarized objects. The patterns of the resulting rotation, exhibited by different objects under the influence of a magnetohydrodynamic effect, originating from the induced Lorentz force, are shown to be dependent on magnetic field polarity. Their dynamic behavior as a function of time resembles those of falsely chiral systems

Orientador: Cesar Costapinto Santana
Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Química
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Resumo: A enantiosseparação de alguns compostos é um brilhante e interessante tópico de muitas áreas da química analítica, principalmente na farmacêutica e biomédica. Sabe-se que apesar dos enantiômeros apresentarem fórmulas e massa molecular iguais, quando expostos em um ambiente biológico podem mostrar grandes diferenças nas suas atividades biológicas. O Fmoc-POAC (9-fluorenilmetiloxicarbonil -2,2,5,5-tetrametilpirrolidina-N-oxil-3-amino-4- ácido carboxílico) é um marcador paramagnético quiral com grande potencialidade de uso como derivado marcador de estruturas peptídicas com funções no organismo animal. De acordo com a literatura consultada, não há relatos de escalas semipreparativas na separação enantiomérica desse composto, extremamente necessária para testes de clínicos-analíticos. Este estudo teve como objetivo o desenvolvimento de métodos inovadores na separação enantiomérica do Fmoc-POAC e obtenção dos parâmetros necessários para um aumento de escala. O presente trabalho realizou uma avaliação experimental através de Cromatografia Líquida de Alta Eficiência (CLAE) para enantiosseparação desse composto, com eluição isocrática e nas colunas quirais de fase estacionária normal e reversa: i) analítica da OD-RH Chiralcel® (150x4,6 mm); ii) Analítica Lux Cellulose-2 da Phenomenex® (250x4,6 mm); iii) Semipreparativa OD da Chiralcel® (150x10 mm); iv) Semipreparativa OD-RH da Chiralcel® (250x21 mm). A partir desses ensaios experimentais, foram estimados os parâmetros cromatográficos da enantiosseparação do marcador molecular Fmoc-POAC nas colunas estudadas, além de parâmetros de transferência de massa e termodinâmicos. Os resultados desse trabalho foram que todas as colunas estudadas apresentaram a possibilidade de separação enantiomérica do Fmoc-POAC através desses métodos relativamente simples comparados aos apresentados na literatura, com destaque para a coluna de fase estacionária normal Lux Cellulose-2 (250x4,6 mm), com resolução de até 18,4. De acordo com resultados obtidos, temos a possibilidade de realizar a separação e recuperação desse composto, lançando-se mão de técnicas cromatográficas de maior rendimento, como sistemas contínuos de separação cromatográfica
Abstract: The enantioseparation of some compounds has interesting application in several areas of analytical chemistry, especially in pharmaceutical and biomedical. It is well known that some compounds with same chemical formulas and molecular mass, when exposed to a biological environment, may show different biological activities. The 9- fluorenilmetiloxicarbonil-2,2,5,5-tetrametilpirrolidina-N-oxil-3-amino-4-carboxylic acid (Fmoc-POAC) is a chiral paramagnetic marker with great potential as a marker for peptide structures with functions in the animal organism. According to the literature, there are no reports of enantiomeric separation of this compound unless in laboratory scale and large scale would be necessary for clinical and analytical testing. This study aimed at the development of innovative methods for the enantiomeric separation of Fmoc-POAC as well as obtaining the necessary parameters for scale up of their purification. The present work carried out an experimental evaluation using High Performance Liquid Chromatography (HPLC) for this compound enantioseparation with isocratic elution and columns with normal and reverse chiral stationary phase: i) Analytical Chiralcel® OD-RH (150x4, 6 mm ), ii) Analytical Lux Cellulose-2 from Phenomenex® (250x4, 6 mm), iii) Semi-preparative Chiralcel OD® (150x10 mm), iv) Semi-preparative Chiralcel OD-RH® (250x21 mm). From these assays, chromatographic parameters were estimated for the enantioseparation of Fmoc-POAC molecular marker beside parameters related to the thermodynamics and mass transfer. The conclusions in this research were that all columns present the possibility of enantiomeric separation of Fmoc-POAC by methods relatively simple compared to those presented in the literature, specially the column with normal stationary phase Lux Cellulose-2 (250x4, 6 mm) with resolution of up to 18.4. The results indicate the possibility of enantioseparation and recovery of these compounds by high yield continuous chromatography techniques
Mestrado
Desenvolvimento de Processos Biotecnologicos
Mestre em Engenharia Química

Obtemos propriedades de um modelo de rede para soluções diluídas de polímeros anfifílicos pequenos a partir do estudo das isotermas de potencial químico. Os resultados obtidos na rede de Bethe e em simulações de Monte Carla são apresentados. Introduzimos os cálculos na rede de Bethe através da mistura simétrica e estendemos o tratamento para dímeros, trímeros e tetrâmeros. O tratamento analítico também é generalizado para copolímeros com grau de polimerização arbitrário. As isotermas de potencial químico apresentam laços típicos de uma separação de fase macroscópica, muito embora se trate de um sistema em que duas densidades (anfifílicas livres e anfifílica na micela) coexistem em um sistema homogêneo. A partir destas isotermas, diagramas de fase são construídos. Nas simulações, propomos uma versão eficiente e revisada do \"teste de inserção\" de Widom. O método é inicialmente aplicado à mistura simétrica. Devido a problemas de tamanho finito, as isotermas de potencial químico indicam laços. Os laços podem ser associados a uma distribuição bimodal na curva distribuição de probabilidades no ensemble grande-canônico. Uma \"construção de Maxwell\" é aplicada nos dados, fornecendo uma curva de coexistência que converge rapidamente para a conhecida solução exata. A presença da coexistência de duas densidades é indicada por laços nas isotermas de potencial químico de soluções de anfifílicas pequenas.
We have obtained the properties of a lattice model for dilute solutions of short amphiphilic polymers from the study of chemical potential isotherms. Bethe lattice and Monte Carlo simulation results are presented. We introduce the Bethe lattice calculations for the symmetric mixture and apply them to dimers, trimers and tetramers. The analytic treatment is also generalized for a copolymer of arbitrary degree of polymerization. The chemical isotherms present loops typical of macroscopic phase separation, albeit for a system in which two densities (free amphiphile and amphiphile in micelle) coexist in a homogeneous system. Phase diagrams are presented. For the simulations, we propose a revised and efficient version of Widom\'s insertion test for mixtures. The method is tried on the symmetric mixture. The chemical potential isotherms present loops due to finite size effects. Loops can be associated with the double peak density probability in the grand-canonical ensemble. A \"Maxwell construction\" procedure yields a coexistence curve which converges rapidly to the known exact solution. Loops are present also in the case of short amphiphile solutions, indicating the presence of two densities.

Orientador: Cesar Costapinto Santana
Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Quimica
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Resumo: O rolipram é um fármaco que possui ação inibidora sobre uma enzima relacionada a processos inflamatórios e tem demonstrado atividade antidepressiva. Ele é comercializado na forma racêmica, isto é, na proporção 1:1 dos seus enantiômeros R e S. No entanto, testes clínicos indicam que o enantiômero R apresenta maior potencial biológico que o enantiômero S. Sendo assim, a separação dos enantiômeros é importante para testes biológicos comparativos de efeitos colaterais. Inserindo-se neste contexto, foi desenvolvido este trabalho de pesquisa com o intuito de estudar a separação deste fármaco pela técnica de cromatografia líquida utilizando coluna empacotada com fase estacionária quiral. Foram determinados os parâmetros analíticos de separação e os dados de equilíbrio e transferência de massa em diferentes condições experimentais. Os resultados mostraram alta eficiência, com número de pratos superando 9000 e fatores de separação na ordem de 1,40. Valores de km superiores a 220 min-1 revelaram baixo efeito dos fenômenos de transferência de massa e conseqüente predomínio dos efeitos termodinâmicos, em destaque à energia entálpica (próxima a -10 kJ/mol para os enantiômeros). Para concentração da mistura até 3,00 mg/mL as isotermas mostraram equilíbrio de adsorção com comportamento linear. Oito colunas cromatográficas foram posteriormente caracterizadas e, a partir dos seus parâmetros analíticos, determinaram-se regiões de separação dos enantiômeros para um sistema cromatográfico contínuo do tipo Leito Móvel Simulado, atendendo diferentes critérios de pureza. Com isso, avaliaram-se as variáveis de desempenho na região de mais alta pureza e o melhor resultado foi simulado a partir de um modelo transiente. Isso possibilitou a determinação do perfil transiente de eluição das correntes de saída e do perfil interno da unidade. As purezas alcançadas para as correntes de extrato e refinado foram 99,99% e 96,74%, respectivamente
Abstract: Rolipram is an enzyme inhibiting anti-inflammatory drug which has also demonstrated antidepressant activity. It is marketed in the racemic form, that is, proportion 1:1 of their R and S-enantiomers. However, clinical tests indicate that the R-enantiomer presents a greater biological potential than S-enantiomer. For this reason their separation is important for comparative biological tests of collateral effects. It is in this context that this research was developed in order to studying the separation of this drug via liquid chromatography using columns packed with chiral stationary phase. Analytical separation parameters, equilibrium and mass transfer data were determined in different experimental conditions. The results revealed high efficiency, with number of plates overcoming 9000 and selectivities in the order of 1.40 for both enantiomers. km values higher than 220 min-1 demonstrated low effect of mass transfer rates and consequently a prevalence of thermodynamic effects; in particular enthalpy energy (next to -10 kJ/mol for both enantiomers). For mixture concentration up to 3.00 mg/mL the isotherms showed adsorption equilibrium with lineal behavior. Next eight chromatographic columns were characterized. Starting with their analytic parameters, the separation regions of the enantiomers were determined for a chromatographic continuous system like Simulated Moving-Bed, with respect to different purity criteria. With that, the performance parameters were evaluated in the highest region of purity and the best result was simulated using a transient model. This permitted the determination of the transient profile of elution in the exit lines and the internal profile of the unit. The purities reached for the extract and raffinate lines were 99.99% and 96.74%, respectively
Mestrado
Desenvolvimento de Processos Biotecnologicos
Mestre em Engenharia Química

Orientadores: Cesar Costapinto Santana, Quezia Bezerra Cass
Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Quimica
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Resumo: O objetivo deste trabalho foi a síntese, em larga escala, da fase estacionária quiral tris(3,5-dimetilfenilcarbamato) de amilose e posterior investigação desta na separação preparativa dos enantiômeros do omeprazol por cromatografia líquida de alta eficiência. O carbamato de amilose, caracterizado por análise elementar e espectroscopia na região do infravermelho, apresentou valores experimentais de CHN próximos aos valores teóricos e absorções no infravermelho próximas a 1720 cm-1, referente ao grupo C=O, a 1220 cm-1, referente à ligação C-N e em 3294 cm-1, referente à ligação N-H. Experimentos de pulsos com soluções do traçador e da mistura racêmica, em diferentes temperaturas e vazões da fase móvel, foram realizados para avaliar a homogeneidade das colunas e sua influência no processo de separação, os coeficientes de dispersão axial e de tranferência de massa e o comportamento termodinâmico da adsorção. Uma análise estatística dos dados de porosidade foi realizada através dos testes t e F mostrando que, com um nível de confiança de 95%, apenas algumas colunas apresentam porosidades equivalentes embora os erros cometidos na determinação da porosidade total e no processo de empacotamento sejam os mesmos. A recuperação do enantiômero de interesse, S-(-)-omeprazol, variou de 10-100% quando a porosidade total sofreu variações da ordem de 3%. Os gráficos de van Deemter mostraram uma relação linear entre a altura equivalente a um prato e a velocidade superficial da fase móvel. O enantiômero S-(-)- apresentou maiores coeficientes de transferência de massa e o enantiômero R-(+)- maiores constantes de Henry. O fator de separação e a resolução apresentaram valores iguais a 1,30 e 1,96, respectivamente, a 40 °C e 1,0 mL/min. Observou-se um decréscimo nos valores desses parâmetros após um determinado tempo de uso da coluna. Os valores negativos de 0 S D e 0 H D indicam um aumento na ordem do sistema cromatográfico e que a adsorção dos enantiômeros da fase móvel na fase estacionária é entalpicamente favorável. O modelo de isoterma de Langmuir foi bem correlacionado aos dados experimentais de equilíbrio no intervalo de concentração analisado. Palavras-chave: fase estacionária quiral, omeprazol, cromatografia líquida de alta eficiência
Abstract: The aim of this work was the synthesis, in large scale, of the amylose tris(3,5- dimethylphenylcarbamate) chiral stationary phase and further evaluate in the omeprazole enantiomer preparative separation by high performance liquid chromatography. The amylose carbamate, characterized by elemental analysis and infrared spectroscopy, showed CHN experimental values close to theoretical values and infrared absorptions at 1720 cm-1 which is assigned to C=O group, at 1220 cm-1 which is assigned to C-N bond and at 3294 cm-1 which is assigned to N-H bond. Pulse experiments with solutions of the inert and racemic mixture at different flow rates and temperature were carried out to evaluate column homogeneity and its influence on separation process, axial dispersion and mass transfer coefficients and adsorption thermodynamic behavior. A statistical analysis of the porosity data was performed through of the t and F tests showing that with 95% confidence level only some columns presented equivalent porosities although the errors made in the total porosity determination and packing process are equal. The recovery of the interest enantiomer, S-(-)-omeprazole, varied of 10 until 100% when total porosity varied in the order of 3%. The van Deemter plots showed a linear dependence between height equivalent to a theoretical plate and mobile phase superficial velocity. S-(-)- enantiomer presented higher values of mass transfer coefficients and the enantiomer R-(+)-omeprazole presented higher values of Henry constants. The separation factor and resolution values were 1.30 and 1.96 at 40 °C and 1.0 mL/min, respectively. It was observed a decrease of these parameter values after a use time of the column. The negative values of 0 S D and 0 H D indicates an increase in the order of chromatographic system and that the enantiomer adsorption from the mobile phase to stationary phase is enthalpically favorable. The Langmuir isotherm model was well correlated to equilibrium experimental data in the range of investigated concentration. Key-words: chiral stationary phase, omeprazole, high performance liquid chromatography
Doutorado
Desenvolvimento de Processos Biotecnologicos
Doutor em Engenharia Química

The topic of this thesis concerns the study of catalytic processes for the synthesis of chiral 3,4,5-trisubstituted piperidine and 2,6-disubstituted morpholine. Substrates possessing an α,β-unsaturated ester and a ketone moiety, able to undergo addition/cyclization cascade reactions with different pro-nucleophiles (thiophenols, acetone cyanohydrin and malononitrile), have been evaluated. Chiral and achiral systems for phase-transfer catalysis have been applied as catalysts. Moderate enantiomeric excesses have been obtained for the morpholinic products and good to excellent values for the piperidinic products, by using cyclopeptoids and quaternary ammonium salts derived from Chincona alkaloids as catalysts respectively. Moreover, the absolute configuration of the 3,4,5-trisubstituted piperidines has been determined through quantomechanical simulations of their chirooptical spectra. Finally, the relative configuration of the 2,6-disubstituted morpholines has been assigned through NMR experiments.

Orientador: Cesar Costapinto Santana
Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Quimica
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Resumo: O fármaco racêmico omeprazol tem sido utilizado no tratamento de doenças relacionadas à acidez gástrica e apresenta atividades diferentes entre os enantiômeros. O enantiômero S, conhecido como esomeprazol, tem maior atividade quanto à inibição da secreção gástrica e tem sido obtido a partir de uma síntese assimétrica. Entretanto, a síntese assimétrica é um processo de alto custo, que exige muitas etapas de desenvolvimento em que apenas um dos enantiômeros pode ser obtido. A separação cromatográfica com fase estacionária quiral (FEQ) tem sido utilizada como uma opção para obtenção de ambos os enantiômeros com elevada pureza ótica. Algumas FEQ têm sido utilizadas na separação do ?mais ou menos?tomeprazol, entretanto a FEQ Kromasil CID-TBB ainda não foi utilizada para essa separação. Neste trabalho, foi realizado o desenvolvimento da separação do omeprazol racêmico utilizando a FEQ Kromasil CID-TBB, e foram determinados parâmetros fundamentais para a separação em escala preparativa. A coluna foi caracterizada através da determinação das porosidades do sistema e avaliação da queda de pressão, apresentado porosidades indicativas de um processo uniforme de enchimento da coluna e baixa queda de pressão. Os parâmetros de separação cromatográfica, determinados a diferentes temperaturas e vazões apresentaram número de pratos, fator de separação e resolução superiores a 1200, 1,24 e 1,74 para a condição extrema de vazão 4,0 rnL/min e temperatura de 40°C. Em condições de concentrações elevadas foi obtido fator de separação superior a 1,27. O coeficiente de dispersão axial apresentou pouca variação entre os enantiômeros, entretanto a transferência de massa global foi considerada relativamente rápida com valores de 21,03 e 17,83 ?min POT. ?l? para S e R-omeprazol, respectivamente. A isoterma de adsorção competitiva apresentou comportamento linear e elevada quantidade de enantiômero adsorvido na FEQ. A entalpia de adsorção determinada mostrou a fenômenos entálpicos regem a separação dos enantiômeros na FEQ avaliada.O estudo de sobrecarga da coluna realizado em concentrações elevadas mostrou a possibilidade da separação do omeprazol racêmico. Os resultados obtidos mostram que a FEQ Kromasil CID-TBB é capaz de separar os enantiômeros do omeprazol em condições de escala preparativa sendo uma alternativa para a produção do S-omprazol
Abstract: The racemic mixture of the omeprazole has been used in the treatment of illnesses related to the gastric acidity and presents different activities between the enantiomers. Enantiomer S, known as esomeprazole, has greater activity how much to the inhibition of the gastric secretion and has been gotten from an asymmetric synthesis. However, the asymmetric synthesis is a process of high cost, that demands many stages of development where only one of the enantiomers can be gotten. The chromatographic separation with quiral stationary phase (CSP) has been used as an option for attainment of both the enantiomers with raised pureness optics. Some CSP have been used in the separation of omeprazole, however the FEQ Kromasil CHI-TBB was still not used for this separation. In this work, the development of the separation of omeprazole was carried through racemic mixture using the CSPKromasil CHI-TBB, and had been determined basic parameters for the separation in preparative scale. The column was characterized through the determination of the porosities of the system and evaluation of the fall of pressure, presented indicative porosities of a process wadding uniform of the column and low pressure fall. The parameters of chromatographic separation, determined the different temperatures and outflows had presented plate number, factor of separation and resolution values larger tham 1200, 1,24 and 1,74 for the extreme condition of 4,0 outflow mL/min and temperature 40°C. In conditions of high concentrations has obtained the separation factor value larger tham of 1,27. The coefficient ofaxial dispersion presented little variation between the enantiômeros, however the transference of global mass was considered relatively fast with 17,83 values of 21,03 and min-l for S and R-omeprazole, respectively. The isotherm of competitive adsortion presented linear behavior and high amount of enantiomer adsorved in the CSP. The enthalpy of the adsortion determinated showed the entalpics phenomena conducts the separation of the enantiômeros in the FEQ studied. The study of overload of the column carried through in high concentrations showed the possibility of the separation of omeprazole racemic. The gotten results show that the FEQ Kromasil CHI-TBB is capable to separate the enantiomers of omeprazol in conditions of preparative scale being an alternative for the production of the S-omprazole
Mestrado
Desenvolvimento de Processos Biotecnologicos
Mestre em Engenharia Química

Orientador: Cesar Costapinto Santana
Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Química
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Resumo: Alguns dos agentes terapêuticos são formulados e comercializados na forma de misturas racêmicas. O fármaco mitotano (o, p'- diclorodifenildicloroetano) é um exemplo dessa mistura. Utilizado apenas para o tratamento do carcinoma adrenocortical. A molécula do mitotano apresenta um carbono estereogênico, indicando a presença de dois enantiômeros. Estudos com o plasma de pacientes indicaram que os enantiômeros do mitotano apresentam perfis farmacocinéticos e farmacodinâmicos diferentes, motivando a separação dos enantiômeros para estudos pré-clínicos mais aprofundados. A separação cromatográfica dos enantiômeros do mitotano foi realizada, no presente estudo, em uma coluna empacotada com fase estacionária quiral tris 3-cloro-4-metil-dimetilfenilcarbamato de celulose e na tris-3,5 dimetilfenilcarbamato de amilose, comercialmente conhecidas como Lux Cellulose-2 e Chiralpak AD, respectivamente. Os experimentos foram realizados nas temperaturas de 15ºC, 25oC, 35ºC e 45ºC, com volume de injeção 20 µl numa concentração igual a 0,2 mg/ml na coluna Lux Cellulose-2 e 2 mg/mL na coluna Chiralpak AD, e vazões da fase móvel variando de 0,2 a 1,6 mL/min. Os parâmetros cromatográficos foram obtidos pelas seguintes fases móveis: (i) hexano puro, (ii) hexano/etanol 99,9:0,1% (v/v), e (iii) isopropanol/metanol 60:40% (v/v). Os fatores de retenção e a seletividade para a vazão de 1 mL/min com o uso de hexano puro como fase móvel e coluna Lux Cellulose-2 foram de 5,12; 5,81 e 1,14, respectivamente. Com a mesma vazão e com a adição de 0,1% em volume de etanol em hexano puro, os fatores de retenção foram de 1,30, 1,40, ao passo que o valor de seletividade obtida foi de 1,07. O tempo de retenção para a fase móvel contendo etanol foi de aproximadamente 8 minutos, que representa a metade dos valores obtidos com hexano puro, com um ganho substancial em tempo de processo de separação. Na coluna Chiralpak AD, utilizando-se a fase móvel isopropanol/metanol 60:40% (v/v), os fatores de retenção obtidos foram de 0,41, 1,35, enquanto que o valor de seletividade foi de 3,29. As curvas de Van Deemter foram obtidas nas duas fases estacionárias. As isotermas lineares e não-lineares foram determinadas. Também se realizaram as análises termodinâmicas da separação através das variações de entalpia, entropia e energias livre de Gibbs da adsorção, demonstrando estabilidade satisfatória das colunas
Abstract: Most therapeutic agents in the form of racemic mixtures are formulated and marketed. The drug mitotane (o, p'-dichlorodiphenyldichloroethane) is an example of this mixture, which is indicated as a single drug for treatment of adrenocortical carcinoma. Its structure has a carbon stereogenic, indicating the presence of two enantiomers. Studies with the plasma of patients indicate that the enantiomers of mitotane have different pharmacokinetic and pharmacodynamic profiles, motivating the separation of enantiomers for preclinical studies in greater depth. The chromatographic separation of these enantiomers in a packed column with chiral stationary phase cellulose tri-3-chloro-4-methyl-dimethylphenylcarbamate and amylose tris - 3, 5dimethylphenylcarbamate was performed. These species are commercially known as Lux Cellulose-2 and Chiralpak AD respectively. The experiments at temperatures of 15ºC, 25°C, °C and 45°C, with injection volume of 20µl at a concentration equal to 0.2mg/ml in Lux Cellulose-2 column and 2mg/mL in Chiralpak AD column, and a mobile phase flow rate ranging from 0.2 to 1.6mL/min were performed. The chromatographic parameters with mobile phases: (i) hexane, (ii) hexane/ethanol 99,9/0,1% (v/v) and (iii) isopropanol/methanol 60/40% (v/v) were obtained. The retention factors for the flow rate of 1mL/min using hexane as mobile phase and Lux Cellulose-2 column were 5.12, 5.81 respectively, showing a selectivity of 1.14. With addition of 0.1% of pure ethanol in hexane (v/v), for the same flow rate, the retention factors were 1.30 and 1.40 and selectivity of 1.07. The retention time for the mobile phase containing ethanol was approximately 8 minutes, which represents half of the value obtained with pure hexane, resulting a substantial gain in the time of the separation process. In Chiralpak AD column and a mobile phase of isopropanol/methanol 60/40% (v/v), the retention factors were 0.41, 1.35 with a selectivity of 3.29. The Van Deemter curve in the two stationary phases was obtained. The isotherms linear and nonlinear were determined. Thermodynamic analysis of the separation was performed, through variations of enthalpy, entropy and Gibbs free energy of adsorption, demonstrating through these analysis, one satisfactory stability of the columns
Mestrado
Desenvolvimento de Processos Biotecnologicos
Mestre em Engenharia Química