Simple labeling of omega-phenylfatty acids by iodine isotope exchange

Within 1 h 15-(p-iodophenyl)-pentadecanoic acid (p-IPPA) can easily be labeled with 123I by iodine-isotope exchange. In contrast to the electrophilic aromatic substitution procedure this method enables a 95% radiochemical yield. The so formed p-123IPPA can be used without the application of any complicated separation techniques. By comparison with commercially available 17-[123I]iodoheptadecanoic acid (123IHA) p-123IPPA shows a remarkably higher uptake in a rabbit heart. Additionally the background activity of p-123IPPA proved to be lower than that measured with 123IHA. p-123IPPA thus indicating its suitability for routine applications in nuclear medical heart diagnosis.