Kuntzsch M.,University of Tubingen |
Lamparter D.,University of Tubingen |
Bruggener N.,University of Tubingen |
Muller M.,ABX GmbH |
And 2 more authors.
Kryptofix® 2.2.2 (Kry) or tetrabutylammonium (TBA) are commonly used as phase transfer catalysts in 18F-radiopharmaceutical productions for positron emission tomography (PET). Due to their toxicity, quality control has to be performed before administration of the tracer to assure that limit concentration of residual reagent is not reached. Here, we describe the successful development and pharmaceutical validation (for specificity, accuracy and detection limit) of a simplified color spot test on TLC plates. We were able to prove it s applicability as a general, time and resources saving, easy to handle and reliable method in daily routine analyzing 18F-tracer formulations for Kry (in [18F]FDG or [18F]FECh) or TBA contaminations (in [18F]FLT) with special regard to complex matrix compositions. © 2014 by the authors; licensee MDPI, Basel, Switzerland. Source
Li P.,University of Heidelberg |
Li J.,Helmholtz Center for Infection Research |
Li J.,ETH Zurich |
Arikan F.,Helmholtz Center for Infection Research |
And 5 more authors.
Journal of Organic Chemistry
A highly stereoselective joint total synthesis of the potent polyketide macrolide antibiotics etnangien and etnangien methyl ester was accomplished by a convergent strategy and proceeds in 23 steps (longest linear sequence). Notable synthetic features include a sequence of highly stereoselective substrate-controlled aldol reactions to set the characteristic assembly of methyl- and hydroxyl-bearing stereogenic centers of the propionate portions, an efficient diastereoselective Heck macrocyclization of a deliberately conformationally biased precursor, and a late-stage introduction of the labile side chain by means of a high-yielding Stille coupling of protective-group-free precursors. Along the way, an improved, reliable protocol for a Z-selective Stork?Zhao?Wittig olefination of aldehydes was developed, and an effective protocol for a 1,3-syn reduction of sterically particularly hindered β-hydroxy ketones was devised. Within the synthetic campaign, a more detailed understanding of the intrinsic isomerization pathways of these labile natural products was elaborated. The expedient and flexible strategy of the etnangiens should be amenable to designed analogues of these RNA-polymerase inhibitors, thus enabling further exploration of the promising biological potential of these macrolide antibiotics. © 2010 American Chemical Society. Source
Holland J.P.,Massachusetts General Hospital |
Holland J.P.,Harvard University |
Holland J.P.,ETH Zurich |
Cumming P.,ABX GmbH |
And 2 more authors.
Journal of Nuclear Medicine
In this era of systems biology, the tide of information derived from "omic" technologies (genomics, proteomics, etc.) has sparked a revolution in drug design, with many industrial and academic programs now embracing the concepts of molecular medicine (i.e., targeting changes in specific proteins or pathways) as measures of treatment efficacy and outcome. This approach has yielded a plethora of new preclinical therapeutics directed at novel targets within oncology. In many ways, the evolution of molecular imaging agents as diagnostic probes mirrors that of chemotherapeutics; yet despite an increasing number of PET and SPECT radiotracers being evaluated in human trials, relatively few agents have found widespread use in clinical oncology. In light of this observation, is it time to reevaluate our strategies for radiopharmaceutical design and use? In this article, we argue that PET has enormous potential to deliver clinically relevant information on disease dynamics that extends beyond mapping the density and spatial distribution of a target. Recent developments in targeting pharmacodynamic biomarkers aim to exploit better the advantages of functional PET by detecting changes in signal transduction pathways, particularly in response to disease progression or treatment in cancer. Copyright © 2012 by the Society of Nuclear Medicine and Molecular Imaging, Inc. Source
Schoultz B.W.,University of Oslo |
Reed B.J.,University of Oslo |
Marton J.,ABX GmbH |
Willoch F.,University of Oslo |
And 2 more authors.
We have developed a new method for automated production of 2-[ 18F]fluoroethyl tosylate ([18F]FETos) that enables 18F-alkylation to provide PET tracers with high chemical purity. The method is based on the removal of excess ethylene glycol bistosylate precursor by precipitation and subsequent filtration and purification of the filtrate by means of solid phase extraction cartridges (SPE). The method is integrated to a single synthesis module and thereby provides the advantage over previous methods of not requiring HPLC purification, as demonstrated by the full radiosynthesis of the potent opioid receptor PET tracer [18F] fluoroethyldiprenorphine. © 2013 by the authors. Source
Preshlock S.,University of Oxford |
Calderwood S.,University of Oxford |
Verhoog S.,University of Oxford |
Tredwell M.,University of Oxford |
And 17 more authors.
[18F]FMTEB, [18F]FPEB, [18F]flumazenil, [18F]DAA1106, [18F]MFBG, [18F]FDOPA, [18F]FMT and [18F]FDA are prepared from the corresponding arylboronic esters and [18F]KF/K222 in the presence of Cu(OTf)2py4. The method was successfully applied using three radiosynthetic platforms, and up to 26 GBq of non-carrier added starting activity of 18F-fluoride. © 2016 The Royal Society of Chemistry. Source