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James Inkster, Msc., SFU/TRIUMF Simplifying the Preparation of 18 F-based Biomolecular Imaging Agents Through ‘Click’ Chemistry CANADA’S NATIONAL LABORATORY.

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Presentation on theme: "James Inkster, Msc., SFU/TRIUMF Simplifying the Preparation of 18 F-based Biomolecular Imaging Agents Through ‘Click’ Chemistry CANADA’S NATIONAL LABORATORY."— Presentation transcript:

1 James Inkster, Msc., SFU/TRIUMF Simplifying the Preparation of 18 F-based Biomolecular Imaging Agents Through ‘Click’ Chemistry CANADA’S NATIONAL LABORATORY FOR PARTICLE AND NUCLEAR PHYSICS Owned and operated as a joint venture by a consortium of Canadian universities via a contribution through the National Research Council Canada LABORATOIRE NATIONAL CANADIEN POUR LA RECHERCHE EN PHYSIQUE NUCLÉAIRE ET EN PHYSIQUE DES PARTICULES Propriété d’un consortium d’universités canadiennes, géré en co-entreprise à partir d’une contribution administrée par le Conseil national de recherches Canada

2 Biomolecules as molecular imaging agents  Why biomolecules? Established synthetic procedures Exquisite specificity

3 Biomolecules as molecular imaging agents  Why biomolecules? Established synthetic procedures Exquisite specificity  Why not? Often requires a complex radiosynthesis Certain species may have issues with in vivo stability, bioavailability Most biomolecules are incompatible with many radiolabelling protocols

4

5 ‘Click’ is a concept Kolb, H.C. & Sharpless, K.B. Drug Discovery Today 2003, 8, 1128-1137. 1,2,3- triazoles epoxide ring openings oximes hydrazones

6 [ 18 F]FPy5yne: an optimized 18 F- based bifunctional molecule  Efficient incorporation of [ 18 F]fluoride via 2-substitued pyridinyl nucleophilic heteroaromatic substitution  Efficient bioconjugation via Huisgen [3+2] cycloaddition reaction Inkster, J. A. H. et al. Journal of Labelled Compounds and Radiopharmaceuticals 2008, 51, 444-452.

7 A typical radioTLC Radiochemical Yield: 89.6%±2.0% (n=4) 18 F -

8 Peptide labelling with [ 18 F]FPy5yne

9 Co-injections: (A) [ 18 F]FPy5yne (B) 18 F-Peptide RCY = 89.6%±2.0% (n =4) (A)(B)

10 Proposed biological applications i.e. Where are we going with all this? 18 F-BBN [ 18 F-bombesin(7-14)]  GRP receptors expressed in ~65% breast cancers*  18 F analogs of bombesin have been prepared 18 F-BVD15  NPY1 receptors expressed in 58%-85% breast cancers*  Attractive target, not yet labelled with 18 F 18 F-Senktide (a NK-3 receptor agonist)  Neuropeptide analog of substance P *Reubi J.C. European Journal of Nuclear Medicine 2002, 29, 855.

11 Same Prosthetic Group, Different Biomolecule

12 Why make radioactive DNA? Robinson, R. PLoS Biology, 2004, 2, 18-20.

13 “I’ve seen the future, brother: it is murder.” –L.Cohen The challenge: the in vivo delivery of nucleic-acid based radiotracers into target cells, followed by retention of the probe by an antisense mechanism Abes, R. et al., Journal of Peptide Science 2008, 14, 455-460. Juliano, R. et al. Nucleic Acids Research 2008, 36, 4158-4171. Debart, F. et al. Current Topics in Medicinal Chemistry 2007, 7, 727-737. 18 F CP Peptide Oligo CP Peptide Oligo 18 F

14 Conclusion & Acknowledgements  The goal: t o employ TRIUMF LS’s expertise in synthetic organic and radiochemistry to develop simple, efficient and high-impact protocols for the preparation of biological radiopharmaceuticals  The Team PET Group (TRIUMF) Tim Storr (SFU) Mike Adam (UBC/TRIUMF) David Perrin (UBC) Fr anç ois Bernard (BC Cancer) Brigitte Guérin (U. de Sherbrooke) Tom Ruth

15 “I’ve seen the future, baby: it is murder.” –L.Cohen The challenge: the in vivo delivery of nucleic-acid based radiotracers into target cells, followed by retention of the probe by an antisense mechanism Some options:  Mismatched support strands  Cell-penetrating peptide-ON conjugates Tat(48-60), Transportan  Guanidino ON 18 F-(R-Ahx-R) 4 -PNA or 18 F-(R-Ahx-R) 4 -PMO Abes, R. et al., Journal of Peptide Science 2008, 14, 455-460. Juliano, R. et al. Nucleic Acids Research 2008, 36, 4158-4171. Debart, F. et al. Current Topics in Medicinal Chemistry 2007, 7, 727-737.

16 Peptide labeling with Tri[ 18 F]fluoroarylborates  an application of technology developed by the Perrin lab.

17 [ 18 F]Fluorination of Sulfonyl Chlorides

18 Scavenging [ 18 F]Fluoride from Aqueous Solutions with Cationic Boranes (19) (20)

19 A Maxim “Synthetic organic chemistry is hard work. Radiochemistry is just hard.” - J. Inkster

20 A Maxim “Synthetic organic chemistry is hard work. Radiochemistry is just hard.” - J. Inkster “And don’t even ask me about radiobioconjugate chemistry…”

21 18 F-labelled Bombensein(7-14)


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