Volume 50, Issue 5-6 p. 515-518
Short Research Article

The design of radiolabeled carbon-14 polymers

Gary Shemilt

Corresponding Author

Gary Shemilt

GE Healthcare Limited, Amersham Place, Little Chalfont, Buckinghamshire, HP7 9NA, UK

GE Healthcare Limited, The Maynard Centre, Forest Farm, Whitchurch, Cardiff CF14 7YT, UKSearch for more papers by this author
Mark Newby

Mark Newby

GE Healthcare Limited, Amersham Place, Little Chalfont, Buckinghamshire, HP7 9NA, UK

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Sean L. Kitson

Sean L. Kitson

GE Healthcare Limited, Amersham Place, Little Chalfont, Buckinghamshire, HP7 9NA, UK

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First published: 30 July 2007
Citations: 4

Proceedings of the Ninth International Symposium on the Synthesis and Applications of Isotopically Labelled Compounds, Edinburgh, 16–20 July 2006.

Abstract

This paper outlines three methods for the incorporation of carbon-14 radiolabels into polymers. The first method discussed used the radiolabeled starting material, [1,6-14C]hexamethylenediamine 2. The reaction of 2 with sodium dicyanamide led to a carbon-14 polybiguanide 3 with a wide molecular weight distribution. An improvement to this reaction was to react 2 with biguanide. This produced 3 with a tighter molecular weight distribution. Modification of side chains in polymers provides a facile route to incorporate carbon-14 labels. This is illustrated in the formation of [14C]carboxymethyl cellulose 6 which resulted in near perfect molecular weight distribution. Another method to incorporate carbon-14 into polymers was the reaction between the sodium salt of polyethylene glycols (PEGs) with [U-14C] ethylene oxide. This resulted in oligomer formation and random labeling in the polymer. This was circumvented by synthesizing carbon-14 PEG esters from the reaction of carbon-14 labeled 2-bromoethyl esters with PEG. This method retained the polydispersity ratio on the reduction of the ester to release the carbon-14 labeled PEG. Copyright © 2007 John Wiley & Sons, Ltd.