Title:Iodination and Stability of Somatostatin Analogues: Comparison of Iodination Techniques. A Practical Overview
Volume: 12
Issue: 23
Author(s): Erik de Blois, Ho Sze Chan and Wouter A.P. Breeman
Affiliation:
Keywords:
iodination, radio-iodination, 127I, 125I, chloramin-T, stability, radiolysis, somatostatin, octreotide
Abstract: For iodination (125/127I) of tyrosine-containing peptides, chloramin-T, Pre-Coated Iodo-Gen® tubes and Iodo-
Beads® (Pierce) are commonly used for in vitro radioligand investigations and there have been reliant vendors hereof for
decades. However, commercial availability of these radio-iodinated peptides is decreasing. For continuation of our research
in this field we investigated and optimized (radio-)iodination of somatostatin analogues. In literature, radioiodination
using here described somatostatin analogues and iodination techniques are described separately. Here we present
an overview, including High Performance Liquid Chromatography (HPLC) separation and characterisation by mass
spectrometry, to obtain mono- and di-iodinated analogues. Reaction kinetics of 125/127I iodinated somatostatin analogues
were investigated as function of reaction time and concentration of reactants, including somatostatin analogues, iodine and
oxidizing agent. To our knowledge, for the here described somatostatin analogues, no 127I iodination and optimization are
described. (Radio-)iodinated somatostatin analogues could be preserved with a >90% radiochemical purity for 1 month after
reversed phase HPLC-purification.
