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University of Manchester

1. Gilks, Sara. Crystallization of chiral molecules from emulsions : DL-threonine, R,S-2-chloromandelic acid and R,S-clopidogrel hydrogen sulphate.

Degree: PhD, 2014, University of Manchester

The objective of this project is to explore the potential for enantiomer separation by preferential crystallization using tailor-made emulsions. Preferential crystallization is widely used as a means of separating pure enantiomers from racemic solutions. This is usually assisted by the addition of seed crystals of one enantiomer for which crystallization yields a conglomerate rather than a racemic compound. Three racemic materials, DL-threonine (stable conglomerate), R,S-2-chloromandelic acid (racemic compound with the occurrence of a metastable conglomerate) and R,S-clopidogrel hydrogen sulphate (stable racemic compound) were chosen based on their different racemic properties to both develop and test the limitations of an emulsion crystallization process. Since threonine is reported to form only a stable conglomerate it seemed an ideal material to use for the development of an emulsion crystallization process. Indeed this was successful with enantiomer enrichments of up to 88 % of the D-enantiomer being achievable. 2-Chloromandelic acid is reported to crystallize as a stable racemic compound but with both metastable (polymorphic) compound and conglomerate known. An investigation into solution crystallization was performed as a means of preparing the metastable conglomerate and also to explore the possibility of developing an emulsion crystallization process in this system. Crystallization of 2-chloromandelic acid yielded both stable and metastable racemic compounds and the metastable conglomerate. Solubility data of the pure enantiomer, stable racemic compound and metastable conglomerate have been determined in acetonitrile and a robust drown-out method developed for consistent preparation of the conglomerate in diethyl ether. In situ UV-Vis spectroscopy studies revealed that in a stirred slurry, the metastable conglomerate converts to the stable racemic compound in approximately 10 minutes at 15 °C. This time scale defined the subsequent process of preferential crystallization from a seeded, tailor-made, non-aqueous emulsion which was successful in providing a route to a product with significant chiral enrichment of the R-enantiomer. R,S-Clopidogrel hydrogen sulphate is a stable compound forming system, which has been reported in patents to form six different polymorphs. The possibility of conglomerate formation is not known. During the course of this work, attempts were made to preferentially crystallize one enantiomer from an already enriched racemic solution. This was unsuccessful, largely due to the fact that the pure enantiomer was found to be more soluble that the enriched starting material. No evidence of a conglomerate was found, but an amorphous form and four crystalline forms of S-clopidogrel hydrogen sulphate (S-I, S-II, S-III and S-IV) have been crystallized from various solvents via different crystallization conditions. Forms III and IV are believed to be present as hydrates which are not currently reported in the literature. The amorphous form and crystalline polymorphs have been characterized using…

Subjects/Keywords: 660; Crystallization, Chiral, Eanantiomer, Emulsion, Threonine, 2-Chloromandelic Acid, Clopidogrel

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Gilks, S. (2014). Crystallization of chiral molecules from emulsions : DL-threonine, R,S-2-chloromandelic acid and R,S-clopidogrel hydrogen sulphate. (Doctoral Dissertation). University of Manchester. Retrieved from https://www.research.manchester.ac.uk/portal/en/theses/crystallization-of-chiral-molecules-from-emulsions-dlthreonine-rs2chloromandelic-acid-and-rsclopidogrel-hydrogen-sulphate(7223b8d8-c95d-42a4-8245-55cae8f31ac1).html ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.618008

Chicago Manual of Style (16th Edition):

Gilks, Sara. “Crystallization of chiral molecules from emulsions : DL-threonine, R,S-2-chloromandelic acid and R,S-clopidogrel hydrogen sulphate.” 2014. Doctoral Dissertation, University of Manchester. Accessed October 16, 2019. https://www.research.manchester.ac.uk/portal/en/theses/crystallization-of-chiral-molecules-from-emulsions-dlthreonine-rs2chloromandelic-acid-and-rsclopidogrel-hydrogen-sulphate(7223b8d8-c95d-42a4-8245-55cae8f31ac1).html ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.618008.

MLA Handbook (7th Edition):

Gilks, Sara. “Crystallization of chiral molecules from emulsions : DL-threonine, R,S-2-chloromandelic acid and R,S-clopidogrel hydrogen sulphate.” 2014. Web. 16 Oct 2019.

Vancouver:

Gilks S. Crystallization of chiral molecules from emulsions : DL-threonine, R,S-2-chloromandelic acid and R,S-clopidogrel hydrogen sulphate. [Internet] [Doctoral dissertation]. University of Manchester; 2014. [cited 2019 Oct 16]. Available from: https://www.research.manchester.ac.uk/portal/en/theses/crystallization-of-chiral-molecules-from-emulsions-dlthreonine-rs2chloromandelic-acid-and-rsclopidogrel-hydrogen-sulphate(7223b8d8-c95d-42a4-8245-55cae8f31ac1).html ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.618008.

Council of Science Editors:

Gilks S. Crystallization of chiral molecules from emulsions : DL-threonine, R,S-2-chloromandelic acid and R,S-clopidogrel hydrogen sulphate. [Doctoral Dissertation]. University of Manchester; 2014. Available from: https://www.research.manchester.ac.uk/portal/en/theses/crystallization-of-chiral-molecules-from-emulsions-dlthreonine-rs2chloromandelic-acid-and-rsclopidogrel-hydrogen-sulphate(7223b8d8-c95d-42a4-8245-55cae8f31ac1).html ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.618008

2. Authesserre, Claire. Système microfluidique pour le contrôle et l'optimisation de l'encapsulation de cellules pour la thérapie du diabète : Microfluidic system for cell encapsulation control and optimization for diabetes therapy.

Degree: Docteur es, Biotechnologie, instrumentation, signal et imagerie pour la biologie, la médecine et l'environnement, 2016, Grenoble Alpes

La transplantation de microcapsules contenant des îlots de Langerhans, amas de cellules pancréatiques régulant la glycémie, montre des résultats prometteurs dans le traitement du diabète de type 1. A l’heure actuelle, il existe encore de nombreux challenges pour augmenter la durabilité d’une greffe fonctionnelle. Le manque de standardisation des technologies d’encapsulation actuelles a suscité un intérêt pour les technologies d’encapsulation microfluidique permettant d’apporter précision et automatisation. Cette thèse s’est attachée à faire progresser deux points de limitations actuelles de ces techniques : la productivité du système et l’état de surface des capsules obtenues.Dans la première partie, nous nous sommes concentrés sur la caractérisation d’un système microfluidique de génération de gouttes à focalisation d’écoulement (MFFD), contrôlé en pression. Des modèles analytiques et numériques ont été développés afin de déterminer les écoulements dans le système. Ensuite, la formation de gouttes a été caractérisée en fonction des paramètres d’entrée du système. Cette étude a abouti à l’obtention de lois permettant de prédire ces paramètres d’entrée afin d’optimiser la fréquence de production de microcapsules d’alginate.Dans la deuxième partie, nous avons développé un système microfluidique permettant de former des capsules de type cœur-couche, afin d’optimiser l’état de surface des capsules. Des premiers essais d’encapsulation d’îlots de Langerhans ont montré le potentiel de ce système dans la minimisation d’une réaction immunitaire vis-à-vis de ces capsules.Ce travail est un premier pas vers l’optimisation du système d’encapsulation, qui à terme, permettra de fournir aux cliniciens des capsules répondant à tous les critères exigés pour la transplantation.

Transplantation of microcapsules containing pancreatic islets, cell clusters regulating blood sugar, show promising results for type 1 diabetes therapy. However, many challenges remain to improve long-term graft functionality. The lack of standardization of current encapsulation technologies has aroused interest in microfluidic systems that enable more precision and automation.This thesis focuses on two of the current encapsulation technologies stakes: improving system productivity and microcapsules surface.In the first part of this thesis, we characterized a pressure-driven microfluidic flow focusing device (MFFD) droplet generation system. Analytical and numerical models were developed in order to determine and predict flow rates. Droplet formation was characterized as a function of the system input parameters. This study led to scaling laws enabling to predict these system input parameters in order to optimize alginate microcapsules production frequency.In the second part of this thesis, a microfluidic system enabling the production of core-shell microcapsules was developed. First experiments of pancreatic islets encapsulation have shown the ability of this system to minimize the immune reaction towards these capsules.This work is a first step towards…

Advisors/Committee Members: Benhamou, Pierre-Yves (thesis director).

Subjects/Keywords: Microfluidique; Gouttes; Fluides complexes; Modélisation; Encapsulation; Diabète; Microfluidics; Droplets; Complex fluids; Modeling; Encapsulation; Diabetes; 660; 616.042 2

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Authesserre, C. (2016). Système microfluidique pour le contrôle et l'optimisation de l'encapsulation de cellules pour la thérapie du diabète : Microfluidic system for cell encapsulation control and optimization for diabetes therapy. (Doctoral Dissertation). Grenoble Alpes. Retrieved from http://www.theses.fr/2016GREAS017

Chicago Manual of Style (16th Edition):

Authesserre, Claire. “Système microfluidique pour le contrôle et l'optimisation de l'encapsulation de cellules pour la thérapie du diabète : Microfluidic system for cell encapsulation control and optimization for diabetes therapy.” 2016. Doctoral Dissertation, Grenoble Alpes. Accessed October 16, 2019. http://www.theses.fr/2016GREAS017.

MLA Handbook (7th Edition):

Authesserre, Claire. “Système microfluidique pour le contrôle et l'optimisation de l'encapsulation de cellules pour la thérapie du diabète : Microfluidic system for cell encapsulation control and optimization for diabetes therapy.” 2016. Web. 16 Oct 2019.

Vancouver:

Authesserre C. Système microfluidique pour le contrôle et l'optimisation de l'encapsulation de cellules pour la thérapie du diabète : Microfluidic system for cell encapsulation control and optimization for diabetes therapy. [Internet] [Doctoral dissertation]. Grenoble Alpes; 2016. [cited 2019 Oct 16]. Available from: http://www.theses.fr/2016GREAS017.

Council of Science Editors:

Authesserre C. Système microfluidique pour le contrôle et l'optimisation de l'encapsulation de cellules pour la thérapie du diabète : Microfluidic system for cell encapsulation control and optimization for diabetes therapy. [Doctoral Dissertation]. Grenoble Alpes; 2016. Available from: http://www.theses.fr/2016GREAS017

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