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Iodine‐125‐terbutaline ( 125 ITB): a new β 2 ‐adrenoceptor probe for lung imaging
Author(s) -
Amin A. M.
Publication year - 2012
Publication title -
journal of labelled compounds and radiopharmaceuticals
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.432
H-Index - 47
eISSN - 1099-1344
pISSN - 0362-4803
DOI - 10.1002/jlcr.2935
Subject(s) - chemistry , terbutaline , iodine , biodistribution , chloramine t , tracer , selectivity , radiochemistry , lung , oxidizing agent , nuclear medicine , medicine , biochemistry , catalysis , physics , organic chemistry , asthma , nuclear physics , in vitro
Development of a selective β 2 ‐adrenoceptor tracer for single photon emission tomography is important for imaging of the lungs. Iodine‐125‐terbutaline ( 125 ITB) was prepared by the reaction of terbutaline with iodine‐125 in the presence of chloramine‐T as the oxidizing agent. The reaction was completed by incubation of the reaction mixture at 70°C for 15 minutes at pH 7. The biodistribution study in mice indicated the ability of the tracer to bind β ‐adrenoceptors in lungs, liver, heart, and spleen. The localization of the tracer in the lungs was high (85%/g at 60 minutes post‐injection) and the highest lung/blood/g ratio was 19.8% at 60 minutes post‐injection. The selectivity of the tracer for the β 2 ‐adrenoceptor was examined by blocking with both β 1 and β 2 ‐adrenoceptor selective antagonists. The results showed reduction of both heart and lung uptake of the 125 ITB tracer, indicating a moderate (not absolute) selectivity for the β 2 ‐adrenoceptor. Copyright © 2012 John Wiley & Sons, Ltd.