HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Lui, B. Articles by Kung, H. F. Search for Related Content PubMed PubMed Citation Articles by Lui, B. Articles by Kung, H. F.

Radioactive Iodine Exchange Reaction of HIPDM: Kinetics and Mechanism

Department of Chemistry, Beijing Normal University, Beijing, China
Department of Nuclear Medicine, State University of New York, Buffalo, New York

Correspondence: For reprints contact: Hank F. Kung, PhD, Building 5, VA Medical Center, Buffalo, NY 14215.

ABSTRACT

In conjunction with single photon emission computed tomography (SPECT), iodine-123 (¹²³I)-labeled N,N,N'-trimethyl-[2-hydroxy-3-methyl-5-iodobenzyl]-1,3-propanediamine (HIPDM) has been used clinically as a regional cerebral perfusion imaging agent. The [¹²³I]HIPDM can be prepared by a simple aqueous exchange reaction in a kit form. We synthesized unlabeLed HIPDM by condensation of 2-hydroxy-3-methyl-5-iodobezaldehyde and N,N,N'-trimethyl-1,3-propanediamine, followed by a sodium borohydride reduction reaction. The kinetics of the radioactive iodine exchange reaction for the preparation of [¹²³I]HIPDM is controlled by the pH, the temperature, and the presence of reductant (sodium bisulfite), and oxidant (sodium iodate). The reaction is a second order iodine-iodine exchange with an activation energy of 30.6 kcal/mole. The mechanism of this reaction probably involves the formation of an active I₊ or iodine free radical, which is sensitive to the presence of a reductant, such as sodium bisulfite.