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Bitte verwenden Sie diesen Link, wenn Sie dieses Dokument zitieren oder verlinken wollen: https://nbn-resolving.org/urn:nbn:de:gbv:9-opus-40389

Interfaces of Supercritical Fluid Chromatography with Mass Spectrometry and Supercritical Fluid Extraction - Applications in Medicinal Chemistry and Bioanalysis

  • Research on the science and the fiction of supercritical fluid chromatography (SFC) has been ongoing for more than five decades. Today, packed column SFC promises speedy solutions to chiral and semi-preparative separation problems, but academia has been reluctant to incorporate SFC into its curriculum, as doubts linger concerning its practicability. This work sought to explore the merits of SFC in hyphenation with electrospray ionization--single quadrupole mass spectrometry (ESI-MS) and supercritical fluid extraction (SFE) in various aspects of medicinal chemistry and bioanalysis within an academic setting. SFC was investigated for its usefulness in assessing the purity and the stability of synthesis products, and the quantification of chiral and achiral metabolites - domains conventionally occupied by high performance liquid chromatography (HPLC). Confronted with analytes prone to hydrolysis (cyclic polysulfides) and UV-induced configurational changes (aza-stilbenes), fast elution by water-free SFC-MS proved complementary to traditional chromatographic techniques. The quantification of antidepressant ketamine metabolites presented an opportunity to assess supercritical fluid techniques within a bioanalytical context. While SFC hyphenated to single quadrupole MS did not reach the sensitivity levels of HPLC coupled to triple quadrupole MS/MS, exploitation of supercritical CO2 reduced analysis times more than six-fold (60 minutes by HPLC vs 10 minutes by SFC). When coopted for both extraction and analysis, SFE-SFC-MS simplified sample preparation and promoted the transition from off- to on-line bioanalysis. Similar results were obtained when SFC was applied to acidic and basic metabolites of the controversial anodyne flupirtine. Again, SFC featured shorter run times but also expanded the target metabolite spectrum covered within one run. Finally, a tiered approach to validation demonstrated the reliability achievable by SFC. Critical applications such as quantification of the newly approved antidepressant ketamine or the recently withdrawn analgesic flupirtine were comprehensively validated according to guidelines on bioanalytical method validation by the European Medicines Agency. Notably, this included the first fully validated chromatographic methods for the putative antidepressant (2R,6R)-6-hydroxynorketamine, and the first report of EMA-conforming quantification by on-line SFE-SFC-MS from urine. Separation scientists find themselves confronted with diverse problems and tools. Although parsing only a microscopic subsection of the available chemical and analytical space, the results obtained here suggest SFC to be a fast and versatile addition to conventional chromatographic methods employed at the intersection of medicinal chemistry and bioanalysis.
  • Überkritische Fluidchromatographie (supercritical fluid chromatography, SFC) wirbt mit schnellen Lösungen für chirale und semi-präparative Trennprobleme, doch scheitert häufig an fehlender Akzeptanz in Forschung und Lehre. In Rahmen dieser Arbeit wurden überkritische Trennmethoden für akademische Fragestellungen aus dem Bereich der medizinischen Chemie und Bioanalytik entwickelt, wobei Schnittstellen aus SFC mit Elektrospray-Ionisation (ESI) und Massenspektrometrie (MS) Anwendung fanden. Darüber hinaus wurde ein ebenfalls auf CO2-basierendes Extraktionsverfahren (die überkritische Fluidextraktion, supercritical fluid extraction, SFE) an überkritische Analyse- und massenspektrometrische Detektionsmethoden gekoppelt (online SFE-SFC-MS). Neben Methoden zur Reinheits- und Stabilitätsbestimmung von Syntheseprodukten erfolgten In-vivo-Studien u. a. zu Ketamin und dessen Metaboliten Norketamin, Dehydronorketamin und 6-Hydroxynorketamin, deren enantioselektive Quantifizierung nach Richtlinie der europäischen Arzneimittel-Agentur (European Medicines Agency, EMA) validiert wurde. Die hier gewonnenen Ergebnisse unterstreichen den komplementären Charakter von SFC zu konventioneller Hochleistungsflüssigchromatographie (high performance liquid chromatography, HPLC) für die orthogonale Bestimmung von Hydrolyse-labilen oder anderweitig instabilen Zielanalyten, sowie die Besonderheiten gekoppelter SFE-SFC-MS-Methoden im Vergleich zu offline Flüssig-flüssig- oder Fest-Phasen-Extraktion.

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Metadaten
Author:Dipl.-Pharm. Robert Klaus HofstetterORCiD
URN:urn:nbn:de:gbv:9-opus-40389
Title Additional (German):Schnittstellen zwischen überkritischer Fluidchromatographie, Massenspektrometrie und überkritischer Fluidextraktion - Medizinisch/chemische und bioanalytische Anwendungen
Referee:Prof. Dr. Andreas Link, Prof. Dr. Maria Kristina Parr, Prof. Dr. Gerhard Scriba
Advisor:Prof. Dr. Andreas Link
Document Type:Doctoral Thesis
Language:English
Year of Completion:2020
Date of first Publication:2020/10/26
Granting Institution:Universität Greifswald, Mathematisch-Naturwissenschaftliche Fakultät
Date of final exam:2020/09/30
Release Date:2020/10/26
Tag:Supercritical fluid chromatography
GND Keyword:4010153-8
Page Number:161
Faculties:Mathematisch-Naturwissenschaftliche Fakultät / Institut für Pharmazie
DDC class:500 Naturwissenschaften und Mathematik / 500 Naturwissenschaften