Abstract
A14-Iodoinsulin is a close biochemical and pharmacological mimic of insulin. Human insulin was labelled in its A chain tyrosine-14 residue by direct iodination with the positron-emitter iodine-124 (β+ = 25.6%; t1/2 = 4.15 days) to provide a radiotracer for imaging with positron emission tomography (PET). Several reagents were compared for conversion of cyclotron-produced [124I]iodide into a reactive species for the labelling reaction. Radiochemical yields from the use of Iodo-Gen®, Chloramine-T, N-bromosuccinimide or lactoperoxidase-hydrogen peroxide were similar [35% (n = 1), 33 ± 9% (n = 10), 32 ± 11% (n = 25) or 33% (n = 2), respectively]. [124I]A14-Iodoinsulin was separated from unreacted insulin and radioactive by-products by tandem reverse phase HPLC and rapidly formulated for intravenous injection by adsorption on a Sep-Pak tC18-Plus® cartridge, followed by elution with 10 mM hydrochloric acid-ethanol (1:1 v/v, 1 ml). This radiotracer can now be obtained in useful radioactivities at high effective specific radioactivity and is now being applied to PET studies of its biodistribution in living subjects.
Original language | English |
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Pages (from-to) | 465-480 |
Number of pages | 16 |
Journal | Journal of Labelled Compounds and Radiopharmaceuticals |
Volume | 44 |
Issue number | 6 |
DOIs | |
Publication status | Published - 2001 |
Keywords
- Human insulin
- Iodine-124
- Iodine-125
- Iodoinsulin
- PET
- Specific radioactivity
ASJC Scopus subject areas
- Analytical Chemistry
- Drug Discovery
- Organic Chemistry
- Clinical Biochemistry
- Molecular Medicine
- Pharmacology