PET imaging of liposomes labeled with an [18F]-fluorocholesteryl ether probe prepared by automated radiosynthesis

Andreas Tue Ingemann Jensen, Tina Binderup, Thomas Lars Andresen, Andreas Kjær, Palle Rasmussen

    Research output: Contribution to journalJournal articleResearchpeer-review


    A novel [F-18]-labeled cholesteryl ether lipid probe was prepared by synthesis of the corresponding mesylate, which was [F-18]-fluorinated by a [F-18]KF, Kryptofix-222, K2CO3 procedure. Fluorination was done for 10 minutes at 165 degrees C and took place with conversion between 3 and 17%, depending on conditions. Radiolabelling of the probe and subsequent in situ purification on SEP-Paks were done on a custom-built, fully automatic synthesis robot. Long-circulating liposomes were prepared by hydration (magnetic stirring) of a lipid film containing the radiolabeled probe, followed by fully automated extrusion through 100-nm filters. The [F-18]-labeled liposomes were injected into nude, tumor-bearing mice, and positron emission tomography (PET) scans were performed several times over 8 hours to investigate the in vivo biodistribution. Clear tumor accumulation, as well as hepatic and splenic uptake, was observed, corresponding to expected liposomal pharmacokinetics. The tumor accumulation 8 hours postinjection accounted for 2.25 +/- 0.23 (mean +/- standard error of the mean) percent of injected dose per gram (%ID/g), and the tumor-to-muscle ratio reached 2.20 +/- 0.24 after 8 hours, which is satisfactorily high for visualization of pathological lesions. Moreover, the blood concentration was still at a high level (13.9 +/- 1.5 %ID/g) at the end of the 8-hour time frame. The present work demonstrates the methodology for automated preparation of radiolabeled liposomes, and shows that [F-18]-labeled liposomes could be suitable as a methodology for visualization of tumors and obtaining short-term pharmacokinetics in vivo.
    Original languageEnglish
    JournalJournal of Liposome Research
    Issue number4
    Pages (from-to)295-305
    Publication statusPublished - 2012


    • tumor Neoplasms (MeSH) neoplastic disease
    • Rodentia Mammalia Vertebrata Chordata Animalia (Animals, Chordates, Mammals, Nonhuman Vertebrates, Nonhuman Mammals, Rodents, Vertebrates) - Muridae [86375] mouse common
    • 10-cholesteryloxy-1-[fluorine-18]fluoro-decanol diagnostic-drug pharmacokinetics
    • [fluorine-18]-fluorocholesteryl ether probe
    • fluorine-18-labeled cholesteryl ether diagnostic-drug pharmacokinetics
    • Kryptofix-222 23978-09-8
    • liposome
    • potassium carbonate 584-08-7
    • 10511, Biophysics - Bioengineering
    • 12504, Pathology - Diagnostic
    • 12512, Pathology - Therapy
    • 14004, Digestive system - Physiology and biochemistry
    • 15002, Blood - Blood and lymph studies
    • 15004, Blood - Blood cell studies
    • 22002, Pharmacology - General
    • 24003, Neoplasms - Immunology
    • 24004, Neoplasms - Pathology, clinical aspects and systemic effects
    • 34502, Immunology - General and methods
    • 34508, Immunology - Immunopathology, tissue immunology
    • Pharmacology
    • liver digestive system
    • spleen immune system, blood and lymphatics
    • automated radiosynthesis method laboratory techniques
    • custom-built fully automatic synthesis robot laboratory equipment
    • magnetic stirring method laboratory techniques
    • positron emission tomography imaging PET imaging imaging and microscopy techniques, diagnostic techniques
    • Biomaterials
    • Methods and Techniques
    • Pharmaceuticals
    • Tumor Biology


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